IBM 3420, 3803 Reference Manual

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IBM

3420/3803

Magnetic Tape Subsystem

Reference Guide

'PREFACE

, . This

reference~guide

and associated video presentation were created by FE Service Plan-

'.

'ning and Support to assist you in maintaining the 3420/3803 Magnetic Tape Subsystem.

Two approaches were taken:

L',

New information

is

included as a result

of

IR

data indicating the areas where more

in-depth knowledge

is

needed.

2.

Current information, which

is

frequently used, has been condensed from the

MLM/

:

Pathfinder and included here.

The guide

is

divided'into four major sections. Each

of

these sections contains informa-

tion which logically

fits into that section. Take the time to glance through the guide and

get an idea

of

what

is

included.

Pay particular attention

to

the "NTF Service Checks" portion

of

each area.

It

is

intended

..

to

give

you a list

of

actions

to

be performed which may help eliminate many call-back

situations.

When

you write a no trouble found

IR

(major unit 960) try to

use

unit/cause

codes which best describe the reported failure symptom

so

that FE SP/S may have a

better understanding

of

areas

of

the machines with intermittent problems.

THIRD

EDITION (January 1980)

This

is

a major revision of,

but

does not make S229-6019-1

obsolete.

Address any comments concerning the contents

of

thls publication to:

IBM

Field

Engineering Service

Planning, Department 96C,

BUilding

005, Tucson, Arizona 85744.

1980

CONTENTS

GENERAL

3420 Subsystem Characteristics. . . . .

3803 Model 3 and 3803

Modell

Differences

Recording Philosophy . . . . . . . .

Understanding

EREP1.

. . . . . . .

Procedure for

Scoping 3420 Tape Unit Sense Bits on Logic Board

3420/3803 Status/Sense Bytes

~

. . . .' . . .

3803-2/3420-3Tiuough 8 Tape Drive

Sense Atialysis. . 3803/3420 Online Tests What

is

Where in the

MLM?

Common

Abends.

. . .

Tools and Test Equipment

MEDIA

, IRD PEP Specialist

Magnetic

Tap~

CommOl1

Media Related Problems

3420 "

Read/Write Service Techniques Read/Write Failure Analysis . Read/Write Head

Service Hints .

3420 Read/Write NTF

Ch~ck1ist

. Tape Developing Procedure Developed Tape Samples . . . 3420 RD/WR Data Flow . . .

,3420

Tape Motion Service Techniques. . 3420 Tape Motion NTF Checklist . 3420

Tape Motion . : . . . 3420 Power Service Techniques 342Q Power NTP Checklist

,

34:20

Power -

DC

Voltages . 3420/625,0- Conversion-Tips . 34

20

PM

Schedule, . .

.' 3420 Sales Feature Codes, . 3420 (All Models) Status

Identifier.

3420 ECA Checklist

."

.

Models3, 5, 7 -

AI'

BO'ard

,.

.

Models 4, 6, 8 -

Al

Board.

.

.Card

Jump~rs

- Models 3, 5, 7

Card Jumpers - Models

4,6,8

'

'Co1l1mon

3420 Part Numbers.

'FlafBelt

Pneuf!1atic

Supply

.,

3 5

9 17 19 20 27 31 35 39

45 47

51

53 61 63 65 67 69 71 73 77 79 83 85 87 91 95

99

~

101 103 117 119

, 121

125 129 131

CONTENTS

(continued)

3803

Modell

Data Flow 3803 Model 2 Data Flow 3803 Microprocessor Instruction

Format.

3803 Microprocessor

Tips.

. . . . .

Current ALU Patches . . . . . . .

Current

3420/3803 Related Software Zaps

3803

Channel Interface . . . . .

3803

DC

Voltages . . . . . . .

3803

Mod

1 to 2 - 6250 Conversion Tips 3803 Conversion Tips from Data Bank 3803 Preventive Maintenance Schedule 3803 Sales Feature

Codes.

. . 3803-1 Feature Identifier . . . 3803-1 Feature Installation Times . 3803-2 Feature Installation Times 3803

ECA

Checklist. .

Bibliography . . . .

Index . . . . .

Reader's Comment Form

iv

139 141 143 145 149 153 155 163 165 169 173

175 177

179

. 183

185

197

199

" GENERAL

3420

SUBSYSTEM

CHARACTERISTICS

Model 3

Model 4 Model 5

Model 6

Model 7 Model 8

Tape

Speed

(Read

or Write)

(ips) 75

75

125 125

200 200

(cm/sec)

190,5

317,5 317,5

508

6250

Read

Access

Time, nominal*(ms)

2.3 1.6

1.1

1600

Read

Access

Time, nominal*(ms)

4.0

2.9 2.6 2.0

1.65

6250 Write

Access

Time, nominal*(ms)

2.1

1.5 0.95

1600

Write

Access

Time, nominal*(ms)

4.0

3.0

2.9 2.0

2.0

1.28

Forward

Start Time, nominal**(ms)

1.8 1.4 1.4

1.1

1.3 .08

Data

Rates

(Kb/sec;Kd/sec):

6250 bpi

470/940 780/1560

1250/2500

1600

bpi

PE

120/240

1201240

200/400 200/400

320/640 320/640

800

bpi NRZI (9-Track)

60/120

100/200 160/320

800

bpi NRZI (7-Tra.ck)

60

100 160

556 bpi NRZI (7-Track)

41.7 69.5

111.2

200 bpi NRZI (7-Track)

15.0

25.0 40.0

Passing

Times per Byte (usec):

6250 bpi

2.133 1.28

0.80

1600

bpi

PE

8.3

5.0

3.1

800 bpi NRZI

16.7 10.0 6.2

556 bpi

NRZI

24.0

14.4 9.0

200

bpi NRZI

66.7

40.0

25.0

Passing

Times, IBG (ms):

6250 bpi

4.0 2.4

1.5

9-Track(PE

and

NRZI)

8.0 8.0

4.8 4.8

3.0

7-Track'(NRZI)

10.0

6.0

3.75

Rewin.~·

Time (2400-foot reel) 60

60 60 60

45

Rewind/Unload Time:

(2400-fQot reel)

(sec)

66

66 66 66

51

Load

Operation, approximate time (in

sec)

to

'tape

unit

ready' (after

'reel/cartridge

is

mounted and

10

10 10 10

7

LOAD/REWIND

is

pressed)

*

Read

access

time

is

the interval fr.om initiation

of

a Forward

Read

command given

to

the

t-ape

control

whe~

tape

is

not

at load point, until the first data byte

is

read

when tape

is

brought up

to

speed

from

stoppe€!

status.

, *Write

access

time

is

the interval

from

the

issuance

of a Move

command given

to

~he

tape

unit

when tape

is

not

at load point,

until

the first data byte

is

written on tape when tape

is

brought up

to

speed

from

stopped status.

**Start

time

is

the

int~rval

from

the

issuance

of

a Move command

to

the tape unit, until tape

attai~s

90%

of

specified velocity. .

1

3803

MODEL 3 AND

3803

MODEL 1 DIFFERENCES

The Model 3

was

designed

to

attach

to

370/ 115s and 125s.

It

is

basically a

Modell

with

three major differences. These differences are required because the 115 and 125

don't

use

a standard 370 channel.

- ALUI

is

modified

to

interface with the channel on the 115 and 125 and translate the

activity to

370 channel sequences which the rest

of

the 3803 understands.

- Hardware logic called

AUTO DATA TRANSFER

is

provided

to

handle the data trans-

fer.

It

includes the byte counter.

- A 32-BYTE DATA BUFFER

is

provided for reading and writing. This large a buffet

is

required in the event

that

data crosses a page boundary. When this happens, time

is

required for ALUI to set the address

of

the new page back into the data address con-

trol in the 115 or 125.

The 3803 Model 3 tape subsystem connects to the Magnetic Tape Adaptor (MT

A)

inter-

face

of

system 3115 or system 3125. The term

MT

A interface refers

to

a set

of

lines over

which control and data signals are exchanged between the control unit and the

MT

A

portion

of

the system.

The basic

3803-3 Control Unit consists

of a MT

A interface attachment section, a data

buffer section, a microprogram section, a read section, a write section, a tape unit

inter-

face and a

CE

section.

I/O commands received from

CPU

through

MTA

are executed with microprograms resident in two independent read-only storage (ROS) units within the 3803-3 Control Unit. One ROS controls the MTA interface lines while the other ROS controls the tape unit interface.

The

3803-3 Control Unit operates in burst mode for all data transfers and executes com-

mands received across the interface, performing one command

on

a single tape unit at a

time.

When

a 3803 Mode13

is

taken offline, all functions from the control

to

the tape unit

become the same

as a Modell

3803.

3

RECORDING

PHILOSOPHY

Types

of

Codes:

NRZI PE GCR

Non-Return

to

Zero Indicating Phase Encoding Group Coded Recording

The progression

of

IBM

digital recording from NRZI

to

PE to GRC

is

the result

of

IBM's

effort to provide the customer with

the lowest cost and highest reliability tape storage

devices.

NRZI coding utilizes a chnage in flux

to

indicate a one and no change

to

represent a zero.

NRZI tapes can be written in densities

of

200, 556 bpi in 7 -track format, and 800 bpi in

9-trace format. (See example A.)

PE coding utilizes a change

of

magnetic flux in the positive direction

to

indicate a one

and a change in the negative direction

to

indicate a zero. PE tapes are written

in

1600

bpi 9-track density only. (See example B.)

GCR coding utilizes a combination

of

NRZI and PE

to

achieve the highest density avail-

able on

IBM

drives. Density for GCR

is

effectively 6250 bpi. (See Example C.)

Group

Coded Recording -

6250

bpi

Group Coded Recording (GCR) offers many advantages over previously used recording

methods. This recording offers higher reliability even with existing tape libraries.

Greatly expanded error correction capability has been engineered into GCR. Higher data rates and lower access times

give

higher throughput and reduced channel time,

re-

sulting in higher system performance. Data

is

compacted on tape, reducing rewind

times, shortening the length

of

tape required for a data set, reducing the number

of reels, reducing mounts and dismounts, and improving overall tape handling. Other advantages exist,

but

here

we

wish

to

discuss only the recording technique.

The data

is

still recorded in blocks, or groups

of

characters. A block

of

data may be

a single character or byte, or a number

of

bytes

as

determined by the programming

system used. The significant improvements in the GCR mode are:

1. The information data

is

recorded at an effective density

of

6250 bytes per inch.

2. The separation between blocks (IBG)

is

0.3 inch, and,

3. That simultaneous errors in any two

of

the nine tracks are corrected automatically.

A GCR block consists

of

a preamble, data and a postamble. The preamble and post-

amble are each

80 bytes long and serve to synchronize the read detection circuits in a

manner similar

to

previous 1600 bpi subsystems. The data portion

of

the block consists

of

the following:

5

RECORDING

PHILOSOPHY

(continued)

1.

For every seven bytes

of

channel data, an

ECC

character (error correcting code)

is

generated and these eight bytes, called a data group, are encoded into ten bytes, called a storage group, which are then written on the tape. There will be as

many

of

these ten byte storage groups

as

there are multiples

of

seven channel

data bytes in the record block. The last group

of

the record block may contain

up to 158 storage groups.

2.

The remainder or last group

of

the channel data bytes (zero

to

six bytes)

is

encoded with whatever

"pad"

bytes are necessary, an auxiliary check character,

and the

ECC

character generated from these into a ten-byte residual group.

This residual data group

is

created for every block recorded, even though no residual bytes are found in the record and will always be ten bytes long. The auxiliary check character verifies read and write operations.

3. End

of

data

is

signaled by a unique subgroup

of

five

bytes immediately preceding

the residual group.

4. Following the residual group, a ten-byte

CRC

(Cyclic Redundancy Check) group

is

encoded. This group, with the auxiliary check character, ensures the integrity

of

the read and write operation including verifying any error corrections which

may have taken place.

5.

Interleaved into the recorded block, after every 158 storage groups,

is

a resync

burst. This burst allows the tape control unit

to

put

back into full operation any track(s) which may have lost synchronization or dead tracked due to tape defects. This action limits dead tracking for greater throughput.

6250 bpi does not relate

to

actual writing density on tape

but

to effective data density

Actual density (9042 bpi)

is

greater due

to

the formatting and enGoding,

but

this for-

matting and encoding

is

transparent

to

the user. The power

of

the format and encoding

method

is

such

that

reliable error correction occurs for any two tracks Simultaneously in error. Also, tracks are not immediately dequeued or 'dead tracked' when an error occurs

as

they were in the past.

It

is

thus conceivable that a block could have errors in

all nine tracks and appear

to

the user

to

be read error-free

so

long

as

only two tracks have

errors at any

given

instant.

6250 bpi, combined with 0.3 inch IBGs, provides for greatly improved channel data rates and access times.

6

RECORDING

PHILOSOPHY

( continued)

NRZI

(Example

A)

o

o o

o

--1

u

L

Write Signal

Analog

Read Signal

Read

Digital Output

PE

(Example

B)

Write

Signal

Read Digital Output

7

RECORDING PHILOSOPHY

(continued)

GCR

(Example

C)

o

J

I

I ..-.-..

________

n

_______

1

L

J I

I

Physical Size

of

a 4K Byte Record

NRZI (800)

PE

(1600)

D

GCR

(6250)

8

UNDERSTANDING

EREPI

EREP

is

designed to help you decide

if

you have a machine problem or defective media,

as

well

as

giving you a good idea

of

how your 3420s are performing. EREPI, with its

enhancement package,

is

even more useful than previous EREP versions. EREPI guide-

lines are presented here

to

assist the

CE

in managing his 3420 account.

IRD (Information Records Division)

is

using a criteria

of

one temporary write error per

5,000 SIOs and one temporary read error per 70,000 SIOs

as

a reference for an average

running

3420/3803 customer account.

We

agree with these numbers with the understand-

ing that they are intended

to

be a national average. They are not a certain indication

of

reliability

to

be obtained in individual accounts because

of

the influence

of

unmeasured

variables (ie, customer block size).

The IRD criteria

is

used in determining temporary read or write error criteria figures

on

the following flowcharts. EREPI parameters should be used

to

produce a 3420/3803 Summary Output with threshold values at one temporary read and fifteen temporary write errors. These are suggested initial threshold values which

CE

may wish

to

change

later.

All

permanent errors should be investigated

to

an acceptable conclusion and all temporary

error quantities

not meeting

criteria

figures

should be recorded and tracked

to

determine

cause

of

outside-criteria conditions.

Sheet 1

9

UNDERSTANDING EREPI

(continued)

Go

to Sheet 7 Temporary

Error

Analysis

Sheet 2

Begin

3420

E R

EP

Analysis

Look

at

"permanent

error

summary"

section

Yes

Permanent Write

If

the

3420

is

now

working properly approach problem as

a media failure.

Try

to

recreate write failure using same

tape

and

3420,

if possible.

Use

pro-

c~dure

shown

on

Permanent

Read

Analysis Sheet 3,

except

perform

wri

te

instead

of

read. Also see M

LM

5A - 105.

10

If

several

permanent

errors are listed

try

to

determine

if one

3420

or

one

volume

of

tape

appears

to

be

at

fault.

I

Permanent

Read

Go

to

Sheet

3 Permanent Read

Analysis

L

______

,

I

Use

Sense

Data

to

Enter

MLM

or

PF

UNDERSTANDING EREPI (continued)

Permanent Read Error

Permanent

Read Error

(From

Sheet

2)

No

Yes

Read

tape

on

tape

unit

where failure

occurred.

No

Locate

and

mark failure

with felt pen - read

tape

on

another

tape

unit

Permanent

Read Error Analysis Chart

Reference

MLM

00-011

Sheet

3

Online: Run "FRIEND" (OLT T0200A) or

have customer run

"ditto"

or equivalent tape-to-tape job using the failing tape

as

input.

Offline:

If

3803

is

available perform read

command from

CE

panel. Turn on

"stop on data flow check" switch.

11

UNDERSTANDING EREPI

(continued

Yes

Return

to

original

tape

unit.

Look for physical

damage

on

tape.

Develop

tape.

Refer

to

section

on

tape

damage.

No

Permanent Read Error Analysis Chart Sheet

4

Refer

to

section on developing tape.

12

UNDERSTANDING

EREPl(

continued)

No

Yes

Repai

r cause of

damage.

Scope failing block off line.

Permanent

Read

Error Analysis Chart

Sheet 5

: Refer

to

tape samples elsewhere in this book.

.

The

purpose

of

scoping a permanent read

error

is

to locate the failure within the

block and determine the cause.

Proceed

as

follows:

1.

Locate the failing block offline.

2. Loop on the failing block:

a. Read forward-backspace on forward

read failures.

b. Read backward-forward space on

backward read failures.

3.

Refer

to

MLM

00-012 for more informa-

tion.

13

UNDERSTANDING

EREPI

(continued)

Scope failing block

on

line.

Call

area technical

assistant

or

branch

office

tape

specialist.

Permanent

Read Error Analysis Chart

Sheet 6

Use

the FRIEND program to scope permanent read errors online: Note: Don't use channel command word

(CCW)

chains. Reading the bad

record breaks the chain.

1.

Locate the failing block with the control unit offline.

2.

I Set up a program loop to read forward-

I backspace or read backward-forward

space whichever

is

applicable.

3.

By

altering the channel command word

(CCW)

byte count, the command-out response to service-in will set the stop trigger in the tape control at any byte chosen. Sync external on the stop

trig-

ger

to examine any portion

of

the block

in detail.

Note:

Detailed observation

of

a PE block

is

difficult due

to

normal distor-

tion

of

the PE signal and the high

amount

of

skew the PE detection circuits can tolerate. Examine several tracks

at

comparable points,

looking for noticeable differences

in levels and waveforms. A record containing excessive phase shift

is usually indicated by multi-track error (MTE) or read write register (R/W Reg) vertical redundancy checks

(YRC). Check the tape unit that wrote the tape for a possible defective write driver. Refer

to

MLM

00-012 for more information.

·

If

you cannot determine the cause

of

the

permanent read error,

save

the tape and any

: information you have gathered for

use

by

· your branch office or region tape specialist.

· A permanent read error can cost the cus: tomer considerable reconstruction and rerun

time. There should be

NO

undefined per-

manent read errors.

14

UNDERSTANDING EREPI

(continued)

Temporary Read Temporary Write Error

Analysis

(From Sheet 2)

I

Look

at

"CUA

Statistics"

section

of

EREP

printout.

I

Look

at

the

three

columns pertaining

to:

• Temp RDS

•

Temp WRTS

•

SIO

Count

I

Using

the

three

columns indicated above, determine if

temporary

error

failure

rate exceeds criteria of:

1.

Temp

write error

per

5,000

SIOs

2.

Temp

read error

per

70,000

SIOs

I

Any CUA

entry

meeting criteria

may be ignored. Those

not meeting criteria should be logged

in

a manner so

as

to

give

the

CE a

method

of

spotting consistently outside

-criteria

volumes

or

CUAs.

(See Note 1)

Sheet 7

Note

1:

One logging

method

would

be

a grid chart

with

CUAs

plotted

along vertical edge

and

volume IDs

plotted

along horizontal edge.

Number

of

temporary

errors could

be

entered

at

appropriate intersections. A con-

sistent

horizontal

pattern

of

error entries

would indicate a possible

tape

unit

problem-

a vertical

pattern

would

indicate a bad

vol-

ume

of

tape.

15

PROCEDURE

FOR

SCOPING

3420

TAPE UNIT SENSE BITS ON LOGIC

BOARD

• Take

3420

offline.

• Disconnect interface connector at 3420.

•

Switch online/offline switch

to

"online".

• Jumper proper

TV

bus-out bits (oIle at a time)

to

ground (D08 pin).

• Scope each sense bit. (Ground Level = Bit On)

Mod 3, 5, 7

K4

Card

<C

~

(+4.4V = Bit Off)

TAPE

UNIT

SENSE BYTES

~

SensoBit

Scope

Points

L2D02

Tie to

Byte

Bit

0

D08

J11

Byte 0 Backward

G10

Byte 1 7-Track

G09

Byte 2

Lamp Failure

L2D04

Bit

1

Not File Protect

Write

Current

Fail

Left Col

Failure

L2D05

Bit

2

EOT

Dual Density

Right

Col

Failure

Mod

4,6,8

K6

Card

G08 G07

Byte 3 Byte 4

High and

Low

Tape

Unit

Serial Number

G05

Byte 5

Air

Flow

High-Order High-Order

Voltage Check Serial Number

Serial Number

G04 Byte 6

Allows

Read

Bus

and

Tach

Pulses

(Crease

Tape)

G03

Byte 7

Load

Button

Left

Reel

Right

Reel

Pressed

Turning Turning

,

17

L2D06

Bit 3

BOT

Alternate Density

Door

Interlock

or

Reset

Key

High-Order Serial

Number

Tape

Present

L2D07

L2D09

L2D10

L2D11

Bit

4

Bit 5

Bit

6

Bit

7

Write Status Start

Unit

Check

Not

Busy

011

= 75

ips

Mod 4,6, or 8 100 = 125 ips

101

= 200 ips

Data Security

Erase

Head

Air

Bearing

Load Failure

Erase

Failure Failure

EC

Level

of

Tape

Unit

Reels

Loaded

Load Rewind

Load

Check

Complete

Note: This procedure should

be

used

only

when

no other method

is

available. (Example:

When

EREP

is

not

available and/or 3803

cannot

be

taken offline.)

3420/3803

STATUS/SENSE BYTES

Bit

0

Bit

1

Bit

2

Bit

3

Bit

4

Bit

5·

Bit

6

Bit

7 Status Byte

Status

Control

Unit

Attention

Modifier

End Busy Channel-End

Device-End

Unit

Check

Exception

Sense Byte

Bit

0 (8)

Bit

1 (4)

Bit

2 (2)

Bit

3 (1)

Bit

4 (8)

Bit

5 (4)

Bit

6 (2)

Bit

7 (1) Byte 0 Command

Reject

Intervention

Required

Bus-Out Check

15-030

Equipment

Check

00-006

Data Check

00-006

Overrun

15-040

(U)

Word

Count

Zero

Data Converter Check

15-020

(U)

15-010

(U)

~

(U)

15-050

(U)

15-070

(U)

Byte

1

Noise

17-370

(U)

(D)

TU

Status A

00-006

~

.'.

TU

Status B

00-006

~

Seven-Track

00-006

Load

Point

00-006

~

Write

Status

00-006

~

File Protected

00-006 ~ Not

Capable

15-060

(U:

Byte

2

Track

in

Error

17-007

Byte 3 Read/Write

VRC

MTEILRC

17-110

Skew

Error

17-160

(D)

End Data

Check/CRC

VRC/Envelope

Check

1600

BPI Set

in

TU

Backward 00-007

P-Compare/C-Compare

17-170

(D)

17-310

(D)

17-530

(D)

17-22017-310

(D)

00-007

17-010

(D)

Byte

4

MP Hardware Error,

Reject Tape

Unit

Tape

Indicate

00-007

Write

Trigger

VRC

Spare

Loop

Write

to

Read

Tape

Unit

Check

00-007

Reserved

for

RPQ

00-007 (E)

~

00-007 (E)

17-020

(D)

00-007

~

Byte 5 New

Subsystem 00-007

New

Subsystem 00-007

Write

Tape

Mark

Check

ID

Burst Check

17-050

Start Read Check

17-070

Partial Record

17-410

Postamble

Error

17-190

Reserved

for

RPQ

17-180

(D)

(U) (D) (D) (D)

Byte

6 Seven

Track

Tape

Unit

Write

Current

Failure

Dual

Density

00-007

3420

Not

Set

to

1600

Model

4/6/8

00-007

Tape

Unit

Model

Identification

00-007

15-090

(E)

~

bpi

00-007

Byte 7 Lamp

Failure

15-090

~

Tape

Bottom

Left

~

Tape

Bottom

Right ~ Reset

Key

15-090

~

Data

Security

Erase Erase Head Failed

15-090

Air

Bearing Pressure

~

Load Failure

15-090

•

15-090

~

15-090

Byte

8 I

BG

Detected 17

-080

Spare

Early

Begin Read Back SAGC Check

16-220

(E)

Slow

Begin Read Back

Slow

End Read Back

Velocity

Retry/Reset

(D)

Check

17-100

(E) (D) Check 00-007 (D)

Check

17-150

(D)

00-007

Byte

9 1

or

2-Track

Correction

Velocity

Change

During

Channel

Buffer

Check

CRC

III

17-54017-590

6250

Tape

Control Spare Spare

Tape

Control

Unit

17-600

Write

16-180

17-600

00-007

Reserved 00-007

(D)

Byte

10

Command

Status Reject Spare

Control

Status Reject

No

Block

Detected

on

Dynamic

Reversal

16-200

Tach

Start

Failure

16-170

Spare

Velocity

Check

16-180

16-160

(E)

16-210

(E)

Write/WTM

16-190

(E)

(E) (E)

Byte

11

B-Bus

Parity

Error

ALU1

Spare

Low

HOS

Parity/Low

IC Hi

IC/Br

Cond/Hi

ROS

Microprogram

Detected

D-Bus

Parity

ALU1

Spare

Br Cond

Error

ALU1

16-030

(B)

~

Parity

on

Branch Instruc-

Register

Parity

16-020

Hardware

Error

16-060

1.6-040 (B)

~

16-050

(B)

~

tion

16-010

(B)

~

(B)

~

(B)

~

Byte

12

B-Bus

Parity

Error

Spare

Low

ROS

Parity/Low

IC

Hi

IC/Br

Cond

Error/Hi

Microprogram

Detected

D-Bus Parity

ALU2

Spare

Br Cond

Error

ALU2

16-100

(B)

~

Parity

on

Branch Instruc- ROS Register

Parity

Hardware

Error

16-130

16-11Q(B)

~

16-120

(B)

~

tion

16-080

(B)

~

16-090

(B)

~

(B)

~

Byte

13

Tape

Control

Features

Tape

Control

Unique

Identification

(Hi,gh-Order Serial

Number

Digits)

Byte

14

Tape

Control

Unique

Identificat

ion

(Low-Order

Serial

Number

Digits)

Byte

15

Tape

Unit

Unique

Identification

(High-Order

Serial

Number

Digits)

Byte

16

Tape

Unit

Unique

Identification

(Low-Order

Serial

Number

Digits)

Byte

17

Tape

Control

Features

Tape

Control

EC Level

Byte

18 Power

Check/Air

Flow.

Spare Spare

Spare

Tape

Unit

EC

Level

Byte

19

TU

7 Primed

for

DE

~

TU

6 Primed

for

DE

~

TU

5 Primed

for

DE

~

TU

4 Primed

for

DE ~ TU

3 Primed

for

DE ~ TU

2 Primed

for

DE ~ TU

1 Priml;ld

for

DE ~ TU

0 Primed

for

DE

•

Byte

20

TU

F Primed

for

DE

~

TU

E Primed

for

DE

~

TU

0 Primed

for

DE

~

TU

C Primed

for

DE ~ TU

B Primed

for

DE ~ TU

A Primed

for

DE ~ TU

9 Primed

for

DE

~

TU

8 Primed

for

DE

I

Byte

21

Load Button

Depressed

Left

Reel

Turning

Right

Reel

Turning

Tap~

Present

Reels Loaded

Load

Rewind

Load

Complete

Load Check

Byte

22

Field

Replaceable

Unit

Identification

•

Byte

23

Field

Replaceable

Unit

Identification

(See

Control/Command

Status Reject)

~

Notes: (B) Sets Bus-Out Check

when

there

are

no

other

bits

on

in Sense

Byte

O.

(D) Sets Data Check (E) Sets

Equipment

Check (U) Sets

Unit

Check

~

May Change Status Between Consecutive Sense

Commands

19

3803-2/3420-3 THROUGH 8 TAPE DRIVE SENSE ANALYSIS

(1

of

7)

When troubleshooting the 3803-2/3420 through 8 Subsystem Use:

This chart:

• For Single Drive failures when sense data

is

available.

•

As

a supplement

to

MLM

00-009 aqp 00-005.

Note: Contamination can appear

as

a multiple drive failure

but

it

is

really drive oriented.

MLM

00-010

is

the normal entry point for the Symptom Index.

MLM

00-011 and 00-012;

•

For

Permanent Read errors plus the tape develop procedure in this

package.

MLM

14-000;

•

For

3803-2 problems.

Tips:

(A) Developing tape can be very helpful

to

determine what kind

of

failure really happened.

(B) Review

3803/3420 Service Aids on microfiche.

(C) Always clean the

R/W

head before adjusting the

AMP

Sensors. A

build up in the head slots can make

it

difficult

to

clean thoroughly

at

times.

(D)

R!W

card

to

head plugging,

if

pins are

not

making good contact,

it

may fail with vibrations. The signal ground connection,

if

not

made, will produce intermittent problems in

R/W.

(E) Compatibility problems between drives can be caused

by

tracking

out

of

adjustment. Or

if

this adjustment is OK, and the tracks are

not

centered

on

tape. Develop tape and place

it

on

the viewer

to

observe. The proper positioning

of

the head to tape relationship

is

done

by

the Skew Plate. A special Skew Plate adjusting tool

is

necessary

to

do this (included in the Reference Plate replacement

kit,

BM

4298806).

(F) Check power supply voltages.

20

3803-2/3420-3 THROUGH 8 TAPE DRIVE SENSE ANALYSIS

(2

of

7)

(continued)

Note: Sense byte bits are in the order

of

their importance except bits in byte 10.

No

Recheck

Symptoms

No

Yes

(A)

If

Ready

is

Off,

Go

to

Sense

Byte

7, Under

Entry

Point

"Au.

(B)

If

Ready

is

On, Go

to

MLM

15·010.

(C)

If

Not

Ready, Go

to

15-090.

(A)

Auto

Cleaner Binding.

(B)

Not

Able

to

Read

Track 1 (6250)

or

Track P 1600.

Dirty

or

Defective

Head.

(C)

Damaged

Tape in Inverse TM Area,

But

After

SAGC Area.

(D)

Read

Card

or

Cable

Loose

(E)

A1

L2

(F) ECA 073

(G) 15-060

(A) Write -

Auto

Cleaner Binding

and

Sticking Over Head.

Note:

SAGC

Not

On.

(B) Write -

10 Burst and SAGC,

Dirty

or Defective

Head

and

Could

be

Edge

Damage

on Tape

at

or

Near

LP.

(C)

Read

or

Write Card.

(D)

Read

Cable Loose.

(E)

5B-000

(F) 17-050

21

[FE127601)

3803-2/3420-3 THROUGH 8 TAPE

DRNE

SENSE ANALYSIS

(3

of

7)

(continued)

No

(A)

Can

be

Turned

on

by

Byte

18,

Bit

0,

if

so,

Swap Power

Interface Board

(9XXXX

Serial.

See

Power Supply

Chart

"C".)

(B) Check the

Fuse

Detect

Ye~

Card.

>~-----1

(C) Check

Kl

Contactor

for

Arcing.

(D)

See

Drop Ready and

Write Current (2nd

and

3rd Blocks Below).

(E) 2A·000 Model 3, 5, 7

2B·000 Model 4, 6, 8

(E) 15-090

(A) Dropped Ready While

Executing a Motion Type Command. .

2A·000 Model 3, 5, 7 2B·000 Model 4, 6, 8

(B)

See

Drop Ready Chart A

>;.::.-----1

and

B Attached.

(C) Reject

TU

Without TU

Check, Drop Busy on

Re· wind, Write Status on During Rewind

or

Drop

Start on a Rewind.

(D)

15-090

and

15-100

(A) Write Card or Cable

to

Write Card

Loose."

>:..::::..-----1 (B) Tape

Unit

A 1 G2 Model

4,6,8

(C) 15-090

(A)

See

Drop

Ready

Chart

"A"

and

"B"

(Attached).

(B) Drop Ready Test Points

>..;;.;;..-----1 on

FTl14.

(C)

2A·000 Model 3, 5, 7 2B·000 Model 4, 6, 8

Sense

Byte 10 Bits

Not

in the Order

of

Their Importance.

0=

Command Status Reject (A)A1K4 (B)

Reseat

Cables

from

Tail·

gate

to

the B3 Board in

3803.

(C) Could

be

a Signal Line

Grounded

to

the Plated

Connector

on

the Cable

Going

from

the

CU

to

TU.

(D) 6A·160

Modell,

5, 7

5B·000 Model 4, 6, 8

(E)

15-020.16·160

22

No Bor WritelWTM (A) Capstan Moved

but

Tape

Did

Not,

Tape Hesitated

or

Stuck. Refer

to

Service

Aid

3.

(B)

Badly

Creased

Edge

of

Tape. May

be

a Tape Handling Problem, Mainly

Shows up,

if

Edge

Crease,

on WTM.

(C)

Two Tracks Missing on WTM, Develop Tape. .

(D)

If

Writing Short Records

and

One

is

Placed

With·

in a

Crease,

the Record

May

Not

Appear on Tape

Because

of

Lift

Off

Due

to

the

Crease.

(E) 5A·000 Model

3,5,7 5B·000 Model 4, 6, 8

(F)

16·190

5 = Tach Start Failure

(A) Capstan Board (B) Capstan Tach (C)

Capstan

Motor

(D) Fiber Optics Bundle

(E) TU Cards·

(See

Step

"H"

for

FRUs).

(F) Check Service

Aid

3,

Mainly

for

Model 3,

5,7

(G) Check Power Supply

Levels,

Vacuum and

Air

Bearing

Pressure.

(H)

6A·000

Model 3, 5, 7

6B·000 Model 4, 6, 8

(I) 16-17

7 = Velocity Check

(A)

Excessive

Drag

in the

Tape

Path, Such

as

Low

Air

Bearing

Pressure, Loose Stubby Column Bars

(Low

Vacuum in

Stubby

Column).

(B) Tape Stick

or

Contamin· ation Mainly Model 3, 5, 7,

Refer

to

Service Aid 3.

Will

Also Happen on

Model 4, 6, 8.

(C)

6A·000 Model 3,

5,

7

6B·000 Model 4, 6, 8

(0)

16·180

[FE127604]

3803-2/3420-3

THROUGH 8 TAPE

DRIVE

SENSE

ANALYSIS

(4

of

7) (continued)

6250/1600 Read

(A)

Primarily a 3803 Failure.

(B)

17-016 and 17-010

(A)

Not

Normally

a Drive Problem_

(B) Hardware Triggers

Out

of

Parity.

Ie)

17-026

and

17-020

(A)

Excessive Drag or Tape Slipping, Clean Capstan.

(B) A 1

K2

in Tape Drive.

(C)

A1H2

in Tape Drive.

(D) Scope

for

Noise on Tach Busy

line

at

Tape Drive Interface.

(E) 17-600 and 16-180

23

(A) Losing a Track

on

WTM,

Usually

Caused

by

Tape

Lift

Off.

Inspect R/W

Head

and

Tape_

(B)

Read

or

Write Card.

(C)

5A-ooo,5B-000

(D) 17-180

(A) Tape

Crease

(B) Oxide Dump

or

Contamination

(C)

5A-000 Model 3,

5,

7

5B-000 Model 4, 6, 8

(D)

17-080

(A)

Read

Head

Magnetized.

(B) Noise

at

Amplitude

Strong

Enough

to

Indicate Bits Before

Actual Record

has

Reached the

Read

Head, Defective

Erase

Head.

(C)

Read

Card

Not

Seated.

(D)

Check Columns and

Glass

Cover

for

Air

Leaks.

(E)

5A-000, 5B-000

(F) 17-170

[FE127603]

3803-2/3420-3

THROUGH 8 TAPE

DRIVE

SENSE

ANALYSIS

(S

of

7) (continued)

No

(A) Heady

Dirty

- Track

Lift

Off. (B) A1J2 TU - Write Driver. (C)

Read

or

Write

Card.

(D) Check

Sense

Byte 2

for

Track.

(E)

RIW

Head

(F) 5A-000 Model 3,

5,7

5B-000 Model 4, 6, 8

(G) 16-160

(A)

Look

for

Tape

Damage

or

Tape Contamination.

(B)

5B-000, 6B-000 Model 4,

6,8 5A-000,

6A-OOO

Model 3,

5,7

(C) 17-070

(A) Generally Accompanied

by

MTE, Envelope Check

Being

Off

Indicates No Drop Out

of

Amp

Sensors.

Check

Read

Card.

(B)

Erase

Head

Not

Erasing all

Tracks.

(C)

5A-000 Model 3, 5, 7 5B-000 Model 4, 6, 8

(D)

17-170

(A) 1600 bpi WTM -

Read

Card.

(B)

Not

Able

to

Detect EOO.

(C) 5A-000 Model 3,

5,

7

5B-000 Model 4, 6, 8

(D)

17-150

(A) Check Byte 2

for

Error

Track.

(B)

Generally

Caused

by

Lift

Off

Due

to

Head

Being

Dirty

or

Contaminated.

(C) A1J2 in TU

- Write Driver.

(D)

Read

or Write Card, Ensure

They

are

Seated

Properly. (E) RIW Head. (F) Write Card Transistor

(5-

Track) Touching the Cartridge Motor.

(G)

5A-000 Model 3,

5,

7

5B-000 Model 4, 6, 8

(H)

17-220 17-310

24

(A) Refer Also

to

R/W VRC.

(B)

17-110,17-310,17-112

Yes

(A) 17-190

Yes

(B) Primarily a 3803

Probl~l!'.

(A) 17-530,17-540

(A) Data

Sensed

During

Erase

or

Erase

Portion

of

WTM.

Suspect Noise from

Read

Card.

Yes

(B) Defective

Erase

Head.

(C)

If

Accompanied

by

Other

Bits They

will

be

the Most

Important.

(D)

17-370

[FE127605]

3803-2/3420-3

THROUGH 8 TAPE

DRNE

SENSE

ANALYSIS

(6

of

7)

(continued)

(A) Track Other Than

"1"

or

"P",

with

Damaged

or

Dirty

Head.

(B)

Scope

Read

Bus

all Tracks.

(C)

58·000

Model

4,6,8

(D) 16·220

(A)

Look

for

Bad

Record on Tape.

(B)

Glazed Capstan. (C) Capstan Control Board. (D) Capstan

Motor.

(E)

Creased

Tape.

(F)

Short

Gaps Created

by

Tape Slip During Write, Glazed Capstan,

or

Tape Stick.

Loss

of

Vacuum

on

Capstan Model

8.

(G) 6B·000,

6A·000

(H) 17·070

(A)

Crease

or

Damage

After

Begin·

ing

All

Ones.

Not

Recognizing

End

of

Data.

(B) End

of

Record Overwritten (by Write Heads) During Backspace Rewrite

Sequence. Tape Slip·

clean the Capstan.

(C) 6A·000, 6B·000 (D) 17·410

(A)

Can

Not

Identify

the

Tracks

to

Correct.

Dirty

Head

Most

Likely.

(8) Check

for

Tape

Damage

and

Also Refer

to

MLM

00·011

and

00-012, Permanent Error

Section.

(C)

Plastic Tach Cover Rubbing Capstan.

(D)

Check

for

ENV

(Envelope)

or

MTE on.

5A·QOO

Model 3, 5, 7

5B·000 Model

4,

6, 8

(E)

17·170

(A)

Very

Unlikely

a Tape Drive

Problem Except in

NRZI

Mode.

(B)

5A·000

Model

3,5,7

5B·000 Model 4, 6, 8

(C) 17·160

2S

(A) With a High Rate

of

MTEs One

Track May

be

Bad

All

the Time,

(1600)

Read

Card. (B) Contamination. (C)

Read

or

Write Card. (D) R/W Head. (E)

5A·000

Model 3,

5,7

5B·000 Model 4, 6, 8

(F)

17·110,17·310

(A)

Primarily a 3803 Problem.

(B)

17·010, 17·530

(A)

1600

or

6250: Look

for

a

Weak

Signal at the Trailing

End

of

the

Record.

(B)

Develop Tape

and

Look

for

the Trailing Portion

of

the

Record

to

be

Over Written.

(C)

Crease

or

Contamination

Across Tape.

(D)

17·530

(A) 17·190 (B) Scope and Determine How

Many Bytes

of

Zeroes There

Are,

if

This

is

a Permanent

Error.

(C)

17·190

(A) Noisy

Read

Card

or

A 1 K2

(6250)

(B) Noise

Read

Card

or

A 1 J2

(1600)

(C)

17·150

(A) Turned on by any 6250/PE

Read

or

Read

Backward Data

Check.

(B)

When

no Data

is

Transferred

to

the Channel

on a Read

or

Read

Backward Operation.

(C)

17·370

[FE127602]

3803-2/3420-3

THROUGH 8 TAPE

DRIVE

SENSE

ANALYSIS

(7

of

7) (continued) ,

(A)

Low

Amplitude

During Write,

Check

for

Dirty

Head

or

Edge

Damage, Such

as

Wavy 5

or

4

Track.

(B) Write Card

or

A1J2.

(C)

Read

Card

(D)

Head

Wear, Outside Track Flutter.

(E)

5A-000

(F) 17-310

(A)

Mechanical

or

Electrical Skew

Out

of

Specification.

(B)

NRZI

Guides

Not

Operating

Proper.

(C)

NRZI

Skew More Critical Than

1600

or

6250.

(D)

5A-OOD

(E) 17-160

(A) 17-310

(A)

See

Sense

Byte 9,

Bit

3. Did

Not

Read

the

Same

CRC Charac-

ter Combination That

was

Just

Written.

(B)

17-530 and 17-590

(A) Data Detected During

Erase

Gap

Operation

or

During

Erase

Por-

tion

of

a WTM Operation. Check

for

Proper Seating

of

Read

and

Write Cards.

(B)

Erase

Head

Not

Erasing Properly.

(C)

5A-000 and 17-370

(A) 5A-000 (B) 17-170

26

(A) 7-Track -

"C"

Compare

is

Set

When

Combined Data

"P"

Does

Not

Match

Read

Data Track

"P".

(B) 17-010

(A) Data Detected During

Read

Stop

Delay, Check

for

Extra Bits

on

Tape. May

Have

Been

Poorly

Erased.

(B)

17-370

(A) Tape Could

Have

Been

Written

With the

NRZI

Guides Held

Out

of

the Tape Path by Some Foreign

Matter. This Allows the Tape

to

be

Written Skewed. Check

Cap-

stan Tracking.

(B)

Edge

Damage

or

Dirty

Head.

(C)

5A-OOD

(D) 17-170

(A) Set

When

CRC Byte Calculated

on a

Read

Operation

Does

Not

Match

the

CRC Byte Written

on

Tape (9·Track

NRZI).

(B) Usually Accompanied

by

Read

VRC

and LRC.

If

so,

Shoot

Read

VRC.

(C)

17-590

(A)

If

Accompanied

by

Read

VRC

or

CRC, Shoot Them First.

(B)

17-310

[FE127606]

3420/3803 ONLINE TESTS

IBM

3420/3803 Online Tests, Listed

by

Section

Test Focus

Test Mode

Test

TYEe

A:

CMD

Sequence Analysis

Control Unit

PE/6250/NRZI

Diagnostic

B:

Control Unit

PE/6250/NRZI

Functional

C:

Control Unit

PE and 6250

Functional

D:

Channel Buffer R/W & Mode Set Control Unit

6250/1600/NRZI

Functional

E:

Basic

Read and Write

Subsystem

PE/6250/NRZI

Functional

F:

6250 Data Path Verify

Control Unit 6250 Only

Functional

G:

6250 Error Detect/Correct

Control Unit 6250 Only

Functional

H:

PE Diagnostic Mode (Part 1)

Control Unit

PE Only Functional

I: PE Diagnostic Mode (Part 2)

Control Unit PE Only

Functional

J:

PE Diagnostic Mode (Part 3)

Control Unit PE Only Functional

K:

PE Diagno,stic Mode (part 4)

Control Unit PE Only Functional

L: Mod 4, 6, 8 Clip Level Check

Tape Unit PE Only Functional

M:

NRZI Control Unit

Control Unit

NRZIOnly

Functional

N:

NRZI Diagnostic Mode (Part

1)

Control Unit NRZIOnly Functional

0:

NRZIDiagnostic Mode (Part 2)

Control Unit

NRZIOnly Functional

P:

7 -Track Functional Tests

Tape

Unit NRZIOnly Functional

Q;

Long Record Write/RDB/Read Subsystem

PE/6250/NRZI

Functional

R:

Write Reliability

Subsystem

PE/6250/NRZI

Reliability

RO:

MAPs

Analysis

Control Unit 3803-2 Analysis

S:

Read Reliability

Subsystem

PE/6250/NRZI

Reliability

T:

Tach Parameters

Tape

Unit

PE/6250/NRZI

Diagnostic

U:

Tach Asymmetry

Tape

Unit

Pp/6250/NRZI

Diagnostic

V:

Start/Stop

Tape

Unit

PE/6250/NRZI

Functional

W:

IBG and Creep

Tape Unit

PE/6250/NRZI

Functional

WR:

MAPs

Analysis Control Unit

3803-2

Analysis

X:

Reel Response

Tape

Unit

PE/6250/NRZI

Functional

Y:

Data Access Measure 1

Tape

Unit

PE/NRZI

Functional

Z:

Data Access Measure 2

Tape

Unit

PE/6250

Functional

AB:

Device Switching

Control Unit

PE/6250/NRZI

Functional

AC:

Control Unit Status

Control Unit

PE/6250/NRZI

Functional

AD:

2-Channel Switch (Part 1)

Control Unit

PE/6250/NRZI

Functional

AE:

2-Channel Switch (part 2)

Control Unit

PE/6250/NRZI

Functional

AF:

2-Channel Switch (Part 3)

Control Unit

PE/6250/NRZI

Functional

AG:

2-Channel Switch (part 4)

Control Unit

PE/6250/NRZI

Functional

BA:

Stress Tape 1

Control Unit 6250 Only Diagnostic

BB:

Stress Tape 2

Control Unit 6250 Only Diagnostic

27

3420/3803 ONLINE TESTS (continued)

Section RO-WR: Error Analysis

These two

OLTs apply

to

the 3803-2 only. The MAPs and the OLTs are designed as

an

integrated package. You should start with

the

MAPs

and

run

the OLTs

as

indicated when

analyzing an error.

All

of

the

3803-3420 OLTs diagnostics can

save

the

error sense data for later analysis

by

OLT 3420RO and OLT 3420WR. The error sense data "save" field

is:

a common area for

all

of

the 3803-3420 OLTs. Therefore,

if

more

than

one OLT is

run

and has errors, the

sense data from the last error in the last

OLT

run

is

available for analysis.

Although the sense data

is

saved for an error in all

of

the OLTs, only OLTs A-G, P, Q, R,

and

S are recommended for

FRU

analysis. The sense data from the other OLTs can be

analyzed,

but

the results may be misleading. This

is

due

to

errors

that

are forced

by

the

OLTs.

OLT

WR

has an EXT= option whereby sense data

to

be analyzed can be entered from

the keyboard.

Example:

DEV j3420WRjEXT= ,SNS=804400

8000002C000008000000C7j

At least the first fourteen bytes (0-13) should be entered. The extent field (EXT=) however, will

not

permit entry

of

all

24

bytes.

How

to

Generate a 'Prewritten' or 'Read Only' Tape

In MAPs,

you

will note references to a 'Read Only' tape. (In several sections

of

the User's

Guide,

you

will note references

to

a 'prewritten tape'. The terms 'prewritten' and 'read

only' are synonymous.) This tape

is

a diagnostic

tool

which should be generated when

the system

is

operating correctly. You should have a 'Read Only' tape generated in 6250

bpi available for analyzing failures. Sense switch Z which

is

in OLTs routines

A-G

gener-

ates 'Read

Only' data in

6250

bpi.

Note: When changing the EXT= parameter, the program must always be called:

Example: DEVj3420A-GjEXT=Zj Example: j3420A-ZjEXT=WZj

not

j jEXT=Zj.

28

3420/3803

ONLINE

TESTS

(continued)

To

generate a 'Read Only' tape (6250 bpi), the OLTs

A-G

are run with first error option

and sense switch

Z on.

Example: DEVj3420A-GjFE,EXT=Zj.

When

the 'Read Only' tape has been generated without any errors, the tape should be

file

protected.

False

Crease Tape Error -

OLT-

OLT T3420I T3420L T3420K T3420M

Messages AIOI08 AI0137 AKOI06 AMOI08

If

byte

17

(EC)

is

not plugged correctly

on

logic AA004.

Prior

to EC733843 bit 6 and 7 should be

01 After EC733843 bit 6 and 7 should be 10 After EC734866 bit 6 and 7 should be

11

R060 OLTs reversed test I and

M.

If

byte

17

is

plugged incorrectly the wrong routine will be run.

o This

is

for a 3803

ModOOl

only. A 3803 Mod002 will be plugged for bit 6 and 7 = 01.

Stress Tape PjN1848621

A prewritten tape used for diagnosing the operating parameters

of

the 3803

Mod

2 has been

been generated by a unique machine for this purpose and cannot be created or duplicated

by any other known method. This tape

is

used in conjunction with OLT diagnostic T3420BA and T3420BB (stress tape 1 and stress tape 2) and should be ordered from the nearest

EPC

just prior

to

converting a 3803

Modell

to

a Model 2. Reference OLT User's

Guide dated March 1974 or later for explanation

of

tests etc. After the tape has been

used

to

check out the converted units the tape

is

to

be returned

to

its original stocking

location for use

by

other conversion sites. The tape

is

not intended

to

be kept

at

the

branch office or customer location. The reason for this

is

that there are only a limited

number

of

these tapes available.

As

recertification

of

the stressed data

is

not possible,

care must be exercised

so

as

not

to

damage the tape. A damaged tape will have

to

be re-

placed with a new one.

The recommended stocking level

is

three tapes

at

each emergency parts center (EPC).

29

WHAT IS WHERE

IN

THE

MLM?

MLMVolume 1

Section PLAN

00

IA-6A

IB-6B

Contents Safety information; table

of

contents (organization

of

publication), a list

of

abbreviations and symbols and the address for ordering the OLTs

User's

Guide.

Notes on how

to

use the

MAPs

effectively; training requirements for using

the

MAPs

effectively, method

of

identifying

ECs

which affect the MAPs,

standard plus and minus voltage levels encountered

;in

the machines, sense byte chart with references to descriptions, a symptom index (page 0-010) for normal entry into the MAPs, a quick index (page 0-009) for entry into the

MAPs

when you have one

of

the symptoms listed there

and you know whether the problem is in the

TU or TCU.

MAPs

for 3420 Models 3, 5, and 7 attached to 3803-2. (Same

as

Path-

finder for these models attached

to

3803-1.)

MAPs

for 3420 Models 4, 6, and 8. Note that Section I B follows Section

6A,not

IA.

Sections 1 through 6

(both

A and

B)

contain

MAPs

for TU power supply, thread/load, basic motion, unload, read/write and capstan motion control problems, in that order.

31

WHAT IS WHERE

IN

THE

MLM?

(continued)

:MLM

Volume 2

Section

7

8

11

12

13

14

15

Contents

TV interface theory

Checks, adjustments, removals and replacements

Tev

power supply

MAPs

Procedures for duplicating failures offline and procedures for performing

various CE panel functions (extracting sense data, restart

on

ALV

error,

etc.)

MAP

procedures for

ALV

hangs or loops, channel busy, timeout, or other

indications where

the

microprogram does not appear

to

be looping nor-

mally (possibly also causing channel hang).

Manual analysis

of

sense data using a prioritized scheme.

MAP

procedures for miscellaneous errors.

32

WHAT IS WHERE IN

THE

MLM?

(continued)

MLMVolume 3

Section 16

17

18

19

20

21

Contents MAP

procedures for equipment checks

MAP

procedures for data checks, including timing charts

of

various data

operations plus second levels

of

the conditions required

to

produce

the

error.

Device switch theory and

MAPs

for problems isolated

to

the device switch.

Board layouts for the

TCU and TU boards showing

the

functions perform-

ed for each card to assist in card swapping.

Logic net cross-reference list. The MAP scoping procedures allow

you

to

identify a failing line and the

FRU

from which this line originates.

If

replacing

that

FRU

does

not

correct

the

problem,

you

may suspect a load-

ing problem

at

the

other

end

of

the

line (net). This cross-reference list

provides the references

to

logic for all line (net) names encountered in

the

MAPs

so

that

you

may more easily pursue problems

of

this nature.

OLTEP error message analysis. Used as directed

by

sense analysis sections

3420RO and

WR

after certain errors encountered

by

sections 3420 F and

G.

33

WHAT IS WHERE

IN

THE

MLM?

(continued)

MLM

Volume 4

Section

40

50

52

53

54

55

57

58

75

80

85

90

Index

Contents Subsystem characteristics, features, etc.

TCV data flow, MPI/MP2 schematic, ROSI trap conditions 6250 read/

write service requirements.

Microprocessor theory

TCV oscillators, clocks, counters and controls, second levels and theory

TV

selection and priority

Loop write

to

read (LWR) purpose, operation and data flow

NRZI data flow and theory

Two-channel switch and device switch theory

CE

panel-

description

of

switches and indicators

Tools and test equipment

Subsystem preventive maintenance

Subsystem installation procedures

34

COMMON

ABENDS

Reference

MLM

00-035

Abends-

Theory

Abend

137,237,413,613,

and 637 may be caused

by

missing tape marks.

Missing

tape marks are caused by:

• Incorrect forward-backward ratio.

•

Loss

of

signal amplitude causing a failure

to

recognize the tape mark.

• Excessive crosstalk, indicating

that

data

is

fed into a dead zone. Data recorded on any

track in a dead zone. will prevent reading a tape mark correctly.

To

check for loss

of

amplitude and crosstalk

use

the failing drive and tape. Find the tape-

mark on the tape that

was

not read correctly. Cycle back and forth across the failing tape

mark with the

CE

panel. Sync on Go Forward (T-AIF2J10) and scope all tracks (read

card test points) and ensure that the signal

is

good on all tracks in zones 1 and 2 (tracks

P,

0, 5, and

2,6,

7).

Measure the amplitude on tracks 1, 3, and 4 (zone 3) and ensure that there

is

less than

140

mv

of

signal (Models 4, 6, and 8 only).

Crosstalk

is

caused by:

• Defective write

card.

• Defective read card.

• Defective R/W head.

• Poor tracking.

If

tracking

is

out

of

specifications

go

to

Capstan Dynamic Alignment

(see

08-150). The drive that wrote or read the tape, or both, could cause crosstalk.

If

the failing tape

is

not available, write a tape on a working tape drive offline, and use

that tape

to

check for crosstalk on the suspected failing drive.

137/637 Abend

Machine

Possible

Causes

Type 3803

Defective

01

A-A2N2

card

,

3803

Defective

01

A-B2F2

35

COMMON

ABENDS

(continued)

237 Abend

Machine

Possible Causes

Type

3420

Large tape creases detected

as

gaps (check

stubby

bar clearance).

3420

Short

records (80 characters) falling within a

tape

crease.

3420

Tape edge damage.

3420

E/C

443935

(6250) - Fix for

short

gap verification during backspace after a write error caused by erratic

tape

motion,

not

installed.

3420

R/W

head forward-to-backward ratio

is

out

of

specifications.

3420

Tape sticking.

3420

Dirty capstan.

3803

Missing Suppress

Out,

intermittently breaking

channel/command word

(CCW)

chain, updating

the

count

but

not

losing a record.

3803

Defective

01

A-B3F2 inbound tag card XC700.

3803

ECA079 - Unexpected interrupt with status

=

'00'

from a non-two channel switch

in

multiple

CPU

2X, 3X, 4X, installation.

36

COMMON

ABENDS

(continued)

413 Abend

Machine

Type

Possible

Causes

3420 Defective

T-A 1 C2

MST card.

3420

Reading 6250 tape in

1600 mode.

E/C 443890 -

Autocleaner sluggish,

not

installed.

3420 Defective

A1

H2

3420

. Defective

T-A

1 L2

3420 E/C 735817 -

Delay Ready after rewind,

Models

to

allow autocleaner

to

return,

is

not

installed.

4,6,8

3420

Damaged

tape

at

load point.

3420

Contamination on the Read/Write head, or the

capstan

is

glazed.

3803 Defective

01

A-A2D2 MST card or defective

01A-A2E2

MST card.

3803

Broken

CCW

chain

without

Unit

Check. Run

an

I/O software trace

for

more problem definition.

3803 ECA079 - Prevent busy in

middle

of

CCW

chain,

not

installed.

3803

ROS

patch

to

ALU1

for

allocated busy

is

not installed.

37

COMMON

ABENDS

(continued)

613 Abend

Machine

Possible Causes

Type 3420

E/C

443935 -Short

gap engineering change

not

,.

installed.

3420

ECA073 - Delay Ready after rewind

to

allow

Models

autocleaner

to

return,

is

not

installed.

4,6,8

3420

Contaminated Read/Write head.

3420

Damaged

tape

at

or

near load

point

3420

Read/Write head forward-to-backward ratio

not

in

specifications.

3803

Defective

01

A-A2N2 card, extra

tape

mark.

Defective

3168/2880

card, high-speed buffer

~

data compare.

OS/VS2

PTF 70751

not

installed.

R017

3803-1

Tape Tracking, leaves a faint

TM

(where

existing files are updated) because

of

the

overwriting

of

the

old EOF TM.

In

this

case

the

writeheads actually

do

the

erasing

of

the

old TM.

3803-1 Defective

01

A-B2F2

3803

Incorrect

UCW

Plugging

Compatibility problems between drives can be caused

by

tracking out

of

adjustment,

or

if

this adjustment

is

OK, the tracks are

not

centered

on

tape. Develop tape and

place

it

on

the viewerto observe. The proper positioning

of

the head

to

tape relation-

ship

is

done

by

the Skew Plate. A special Skew Plate adjusting tool is necessary

to

do

this {included in the Reference

Plate replacement kit,

BM

4298806 stocked at the

(EPC's) E level parts centers}. Reference SA 9 and SA 10.

38

TOOLS

AND

TEST

EQUIPMENT

The tools and test equipment listed

in

this section are required

to

properly service 3420

Magnetic Tape Units and 3803 Tape Controls.

Kept

at

the Regional Office

Part Name

8216729 ROS Address Tracer

8218343 Variable Frequency Oscillator

(VFO)

Kept

at

the Branch Office

Part

451064 453522 453585

4169639

2515376 2515390 2515401 2523723 5861448 5861455 5861452 8215414

Name

Master

Signal Level Tape (see Notes 1 and 4) Degausser (see Note 1) Developing Solution

*Digtec

251

Meter (Digitec

201

Meter, PIN 453046, may be used

if

it is available) Scale, 0

to

6 pounds (belt adjustment) Capstan Prealignment Gauge Capstan Adjustment Wrench (rear adjustments) Reel Motor and Hub Adjustment Tools (see

08-460)

Capstan

Adjustment Wrench (front adjustments)

7-Track NRZI Threshold Adjustment

Card PE Threshold Adjustment Card Dual Density Threshold Adjustment Card ROS Patch Card

(see Note 1)

Kept at

EPCs

Part

4298806

1848621

Name

Reference/Skew

Plate Replacement Tool Kit (Ref

SA-9

and SA-l 0)

6250

BPI

Stress Tape (see Note

3)

*Trademark

of

United Systems Corporation

39

TOOLS AND TEST EQUIPMENT (continued)

Kept

at

the Customer's Account

Part 8493001

352465

453500

453504 453522

1765342 1846251

1846252 2515745 2513154 2501611 2512063 2515390

Notes:

Name Tape Transport

Cleaner Scratch Tape Oscilloscope (Model 453, 454, 561, 545, 766H or equivalent) Tape

Cleaning Kit

Master

Skew Tape (see Notes 1 and 4) Manometer 30 inch (two needed for series connection) (See Notes 1 and 2) Tee and Hose Assembly (see Note 2) Tape Development Solution Tape

Unit Tester Shim, Right Reel Hub Adjustment Hex Wrench, Right Reel Hub Adapter Hose (see Note 2) Pressure Divider (see Note 2) Tape

Unit Cleaning Brush Crimper (supplied by marketing representative) Capstan

Box.

Wrench (rear adjusting capstan only)

1.

Discussed in more detail in the

MLM

2. Not needed

if

pressure/vacuum gauge PIN 5495384 is available

3. 1848621 stress tape used for model conversions stocked at

EPCs.

See

Also see page 29 for description.

4.

Order through IRD per the "Order Processing" section

of

the IRD Branch

Office Manual.

40

TOOLS AND TEST EQUIPMENT

(continued)

Master

Tapes

Master skew tapes and master signal-level tapes are manufactured

to

rigid specifications.

They are the standards that are used

by

CEs

to

obtain optimum tape unit performance.

Because tape unit performance

is

directly affected

by

the accuracy

of

these master tapes,

the following precautions should be

taken~

1,

Use

master tapes only for their intended purpose.

2. Handle tapes with care.

3. Make only full-reel passes in order

to

have even wear throughout the length

of

the tape.

4. Identify master tapes

as

such and mark the reels with the letter

"m,"

as

a reminder

to

make full passes only.

Master

Skew

Tapes

Master skew tapes have a density

of

800 fci and are written with one solid bit across the

width

of

the tape. These tapes are written

on

a specially adapted tape unit at the Tape

Test

Center with accuracy held

to

within 0.375 usec total skew between the leading and

lagging bits

of

a 112 ips tape unit.

The master skew tape will run

off

the reel when reading forward because it

is

written

with no interblock gaps (IBGs). In order

to

create an IBG and

save

time during skew

adjustments, make the follOwing alterations

to

the master skew tape:

1. Read the master skew tape forward

to

the end

of

tape (EOT) reflective marker.

2. Install a write enable ring.

3. Write one record

of

any size beyond the EOT marker.

4. Remove the

wr~te

enable ring.

5. Rewind the tape.

After the preceding one-time preparatory steps, set the tape control

CE

panel

as

follows

when you

use

the skew tape:

1.

Command I-Read Forward

('02')

2. Command 2-Read Backward

('~C')

3. Command 3-Read Forward

('02')

4. Command 4-Read Backward ('OC')

The master skew tape will read forward

to

the end

of

the reel, read backward, and repeat

the cycle. This permits checking skew from the rear

of

the tape unit without manipul-

ating the controls.

41

TOOLS AND TEST EQUIPMENT

(continued)

Master

Signal-Level

Tapes

Master signal-level tapes have the ability

to

produce a signal to within

±2%

of

the primary

master. (A primary master, which

is

established

as

an

IBM

standard,

is

the base for in-

strument alignment.)

All

new master signal-level tapes are checked at 3200 fei and 800 fci. The suffix letter

"A"

is

added

to

the part number to allow field identification

of

3200/800/556 fei tapes

as

opposed

to

the former 800/556 fei tapes. Thus, for example, a master

Signal-level

tape

checked out at

both

3200 fei and 800 fei would have PIN 432152A.

Degausser

CAUTION:

Do

not

use

the degausser near magnetic tape

of

any kind because it erases

the information on tape. Power-down the tape unit.

To degauss the read/write head:

1.

Remove magnetic tape from the tape unit. Do not place the tape on top

of

the tape

unit.

2.

Plug degausser into 110 Vac receptable.

3. Press the pushbutton on the degausser while it

is

at least one foot (30,5 cm) away

from the read/write head and move it slowly toward the head.

4. Hold the degausser

agai~st

the front surface

of

the head for about ten seconds.

5. Pull the degausser straight away from the head very slowly

to

a distance

of

at least

one foot (30,5 cm) and release the pushbutton.

MST

Board Ordering

Instructions for ordering a 3803

MST

board for field replacement. The following infor-

mation must be supplied when placing the order.

1.

Machirie type and serial number

2. Features on the

3803

3. Part number

of

the

MST

board

4.

EC

level

of

the board

5. REAs installed (if any)

6. Board location (example -

B3)

7. Name and phone number

of

person to contact in case the plant needs further informa-

tion. Note: There are some

3803 boards with EC733806 written on the sticker. This

is

a non-existent

EC

number. The

EC

number should be EC733801.

42

TOOLS

AND

TEST

EQUIPMENT

(continued)

8. Refer to AA005 in the logics for feature wiring before installing the board. (five pages 3803-2 and three pages 3803-1)

9.

Have

sufficient quantities

of

resistors

on

hand.

See

part numbers below.

3803

MST

Flat Cable Replacement - see General

CEM

251.

3420

MST

Flat Cables Replacement:

5802133 uses

580218048

in.

5802181 64 in.

5802134 uses

5802182

48

in.

5802183 64 in.

3803 Tie UplDown Resistors:

Wire

Color Resistance

2520936

2520942

Tie-Up

Blue

Tie-Down Yellow

51n

620n

43

Tie

to

D08 B06

MEDIA

IRD

PEP

SPECIALIST

If

you have reason

to

believe the customer's tape library contains tapes

of

poor

quality or

if

you need expert assistance in finding methods

of

locating bad tapes then

consider contacting your IRD PEP Specialist.

The PEP (performance Evaluation Program) Specialist

is

a person expertly trained in all

phases

of

magnetic tape evaluation.

He

can provide assistance in most any area relating

to

media problems and should be a useful resource for the

CEo

Your field manager should be consulted before involving the PEP specialist.

45

MAGNETIC

TAPE

Most

of

the recording media in today's digital record environment

is

a polyethylene

terephthalate film, (mylar*), coated on one side with a flexible thin layer

of

ferro-mag-

netic material. The tape is slit

to

.498 ±

.002"

wide and reflective stickers are mounted

at each end

to

mark the beginning and end

of

the usable area

of

tape. Tapes come in

two standard lengths -

1200 and 2400 feet.

Under normal operating conditions tape should operate at least

40,000 passes before a

permanent read error is encountered. This

is

possible only when tape

is

stored in the

proper environment and handled properly when in use.

Tape can deteriorate due

to

conditions encountered

in

storage, handling, or operating

on

drives. This degradation will show up

as

an increasing number

of

temporary write or read

errors during its use until the damage gets extensive enough to cause a permanent error.

When storing tape

it

should be stored in an area where the temperature

is

between

40

degrees

to

90 degrees F

(4

degrees

to

32

degrees C) and 20 to

80

percent relative humidity (nominally 70 degrees F at 35 percent relative humidity). To operate, tape should be at

60 degrees

to

90

degrees F (16 degrees to 32 degrees

C)

and 20

to

80 percent

relative humidity (nominally 75 degrees F at 45

to

50 percent relative humidity). When

tape

is

exposed

to

temperatures in excess

of

the above criteria degraded operations may

occur. Tape should be acclimated

to

the operating temperature for at least

24

hours

before use

if

large environmental changes are encountered in storage or use.

When

a reel

of

tape exceeds a specified number

of

errors it

is

recommended

the

tape be

removed from service. The specified number

will vary from customer

to

customer.

It

is

dependent

on

several parameters

of

this

total

system operation.

Details

of

tape properties essential for

IBM

tape units are found in

IBM

manual,

\GA32-0006, tape specifications for

IBM

one-half inch tape units

at:

556,800,1600,

and 6250 bpi.

*Trademark

of

E. L du Pont

de

Nemours & Co. (Inc)

47

MAGNETIC

TAPE

(continued)

Tape

Quality

Reference GA32-0006, Tape Specifications for

IBM

One-Half Tape Units.

These paragraphs have been added

to

provide IBM's recommendations

as

to what quality

a tape should contain when new (paragraphs 1 and 2) and

as

it

exists in the library (para-

graph 3).

1. Sho_rt-Length Reliability

Definition - J'he ability

of

the tape

to

withstand the wearing action encountered

during repeated references

to

a short

file

of

data.

Recommendation - Under the conditions

of

the

follOwing

test procedure the tape

should average at least

40,000 read passes before a permanent error

is

encountered.

Procedure - Write a length

of

tape from load point with ten, 2000-character rec-

ords (PE recording).

No

write skips shall be allowed during the write pass. Then read the ten records (read forward/rewind) repeatedly until a permanent read error occurs. Perform this test with sufficient go-down time

(20.0 milliseconds)

to

en-

sure that the tape comes

to

a complete stop for each record.

2. Long-Length Durability

Definition - The ability

of

the tape

to

resist the wearing action encountered while

cycling full length

on

a tape unit. This

is

not a test for end

of

life.

48

MAGNETIC TAPE

(continued)

Recommendation - At least 90 percent

of

the tapes tested should meet the follow-

ing criteria:

Tapes tested for use at

3200 fci should not average more than three write errors

per pass, or exceed ten write errors on any single pass, for a minimum

of

200 for-

ward passes on any

IBM

tape unit

that

operates at 3200 fci.

Procedure -

Use

the appropriate tape unit and associated tape control for this test.

Write a

2400-foot (732m) length

of

tape in start/stop mode with 2000-character

records (PE recording) on each pass. In order

to

determine the effect

of

wear part-

icles generated during the test do

not

clean the tape unit between passes.

3.

library

Quality

Definition - A measurement

of

the quality

of

tape

is

its write

ca

pabiltiy.

Recommendation - Tapes with more than twenty write skips are not recommended.

If

tapes

of

this type are used, more frequent cleaning

is

recommended.

Procedure -

Use

the appropriate tape unit and associated tape control for this test.

Write a

2400-foot (732m) length

of

tape in a start/stop mode with an average block

length

of

1.5 inches (38.1 mm).

By

use

of

Volume Error Statistics, a measure

of

the quality

of

the tapes and library can be determined. Volume Error Statistics are

available in the

IBM

Operating Systems, OS, DOS, and VS.

49

COMMON

MEDIA

Unevenness

of

Tape

Wind

(Staggered

Wraps)

3420/3803 Service

Aid

4

The manner in which a tape stacks on a reel when rewound

is

a product

of

three factors: The drive, the tape, and the reel. These all contribute: however, in an individual case, any one

of

these may be predominant. Some items

that

are pertinent

to

this matter are:

1. Some irregularity

of

wind

is

to be expected.

It

is

caused by aerodynamics (escap-

ing

air forming a cushion between layers), and static electricity which will attract

or repel the tape

to

or from a flange in varying degrees

as

the tape

is

wound.

2. A perfectly smooth

wind (from a 3420 drive)

is

not necessarily desireable

as

it

tends to indicate the tape

is

being forced against one

of

the flanges or other guiding

surfaces.

3.

If

the wind

is

irregular, no damage

to

the tape will result unless poor handling

practices are followed; ie, pressure applied

to

the reel flanges causing a tape edge to

be

bent over. This may

be

due to improper stacking

of

multiple reels not in con-

tainers or cartridges designed to be stacked or squeezing the flanges while handling

or mounting a tape.

4. The flanges

of

the reel are not designed to guide the tape or help it wind smoothly.

The flanges are there only to protect the tape during shipping and handling, and

then only to protect it from something bumping the tape edges, not from pressures

of

such force

as

to

bend the flanges.

Devices can be developed which will wind the tape smooth.

You will note new tapes re-

ceived

by

customers have a smooth wind. The field situation does not warrant installing

and maintaining such a device on field drives.

With each complaint or concern

of

staggered wraps, the best approach

to

the problem

is

to

adjust the drives

as

accurately

as

possible,

so

they are not producing

~nnecessarily

poor winds. Inspect the drives for any possible condition that may indicate wear or interference in the tape path. After it has been determined that the mechanical alignment

of

the transport

is

acceptable, the customer should be instructed on proper handling

techniques for magnetic tape.

51

COMMON

MEDIA

(continued)

Z-Folds

Loose wraps are usually caused by poor handling or poor leader

on

tape. When

tape

is

loaded

on

machine the loose outer wraps are pulled tight against loose wraps further in

causing Z-fold.

Z-folds

can be avoided

by

adequate customer controls in tape handling, properly crimp-

ing end

of

tape, and library management. Also, beware

of

poor temperature control and

drives with different rewind tensions.

The

IRD

representative can provide a complete seminar which provides a comp-

rehensive approach

to

all areas

of

magnetic tape care and handling.

52

3420

READ/WRITE SERVICE TECHNIQUES

Temporary jPermanent Errors

The primary cause

of

write data checks

is

the type caused by a loss in signal from the tape

on readback during write.

On the 3420 tape subsystem when tape

is

written the ampli-

tUde\s checked

to

ensure there

is

sufficient amplitude written on tape

to

be read at a

later date. This write checking level (threshold)

is

higher than the threshold at which the

tapes will eventually be read.

If

the amplitude

of

the read signal goes below the threshold a temporary write error occurs and the error recovery program (ERP) takes control. ERP backs the tape up to the last gap, then performs an erase

gap

before retrying the

write operation.

If

the write

is

then error-free one temporary write error

is

logged and

normal operation continues.

If

the retried write operation again fails another erase

gap

then write

is

performed. This

is

continued until the write

is

successful or until fourteen

tries to write the record have occurred.

In

that event one loop write-to-read command

is

tried.

If

successful, one more erase gap, write

is

attempted.

If

it again fails (fifteenth

time) a permanent write error

is

posted (the temporary write errors associated with this

failure are then discarded).

If

the write command

is

successful on, for instance, try number 10 EREP would show

nine erase gaps (actual number)

but

only one temporary write error. The reason for this

is

that write errors occurring while ERP has control are not logged

to

EREP while

all

erase

gaps

are.

Several causes

of

data check on tapes are:

1. Defects in oxide on tape

2. Dirty tape

3. Dirty tape path

4.

Edge

damage on tape

5.

Contamination on head

6. Tape device failures

When

excessive

e~rors

are encountered on a tape, corrective action should be taken. The

first action

would be to inspect the tape path for contamination.

If

any foreign material

is

present,

it

should be removed by using normal cleaning procedures.

If

error persists the

tape should be tried on a second tape device (if available) or a different, known good, tape

should be put

on

the failing tape unit. In this way the error condition can be isolated

to

the tape or

to

the tape unit.

When

a tape with large numbers

of

errors

is

found in a cus-

tomer library it should be identified and corrective action

by

customer should be taken.

This can include cleaning and recertification

of

the tape or removing the tape from the

tape library.

If

a tape shows signs

of

damage or contamination it should be removed be-

fore it can cause damage

to,

or cause contamination

to,

other tape in the customer's

library.

There are many other types

of

errors and causes

of

errors. The several covered in the

above text are the most common causes and are the majority

of

the types

of

errors the

CE

will encounter in the. field.

S3

3420

READ/WRITE SERVICE TECHNIQUES (continued)

Read Amplitude Adjustment (Amp Sensors)

.Read amplitudes are adjusted prior to shipment. They should normally be readjusted

only

if

the read/write head or the read card

is

replaced. Before performing the adjust-

ment procedure:

(MLM

ref 08-310, 46-8, or 08-290, 3-5-7)

1. Ensure that the

-4V

dc and

+6

V dc supplies are correctly adjusted before adjust-

ing the read amplitudes.

(See 08-570,

DC

Power Supply Checks/Adjustments.)

2.

Clean the read/write head and tape path before making adjustments.

Tape Slipping

Tape slip usually occurs during dynamic reversal while performing an erase gap com-

mand. Tape slip causes the tape to be incorrectly positioned.

When

the write head

becomes active it then erases part

of

the previous record. (The record before the

error record that the erase gap command

was

supposed to erase.)

Developing the tape shows the postamble missing on the previous record. For details see

Tape Developing Procedure in 3420/3803 Reference Guide.

~IIIIIIIIIIIIIIIIIIIIIIIIILr

l

FEraSedGap

!lllllllllllllllllllllllllllllllllllf

t I J t t

Load

Point

Itl

Erased

Record

L-

Erased Postamble and Part

of

Data

on

Good Record

Possible Causes

of

Tape Slip:

a. Loss

of

capstan vacuum on Model 8 b. Drag in the tape path. c. Dirty air bearings. d. Low air pressure. e. High or low vacuum. f. Door

glass

leakage.

g.

Damaged capstan surface.

h. Possible media problem.

Note: Refer

to

3420 Tape Motion section

as

well for tape slip problems.

54

3420

READ/WRITE SERVICE TECHNIQUES

(continued)

Noise or Bits in the Interblock Gap

To

detect interblock gap errors, sync scope

on -Go

Forward. Read forward and backward over the failing record. Display the record in both directions and look for noise in the gap (see diagrams on

MLM

SA-lIS and SB-02S). Developing the tape with noise

in the interblock

gap

shows bits written in the area between two records (sometimes

faintly recorded).

Record

~

~1~IIOOIIIlIlIlIIIIlIlI~1I1I1

.,

Load Point

Possible Causes:

Record

t

I

~IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII~IIIIIIIIIII

t

Faint Line Approximately .050,

(1.3 mm)

After

End

of

Record.

a. Gaussed or magnetized read/write head. b. Erase head not working.

Bit

Packing

Record

t

1~llllllt

Bit packing

is

due to varying capstan speed or tape slipping. For scoping procedure

see

MLM

SA-lIS or SB-02S.

Also

see

3420 Tape Motion Service Techniques.

Possible Causes

of

Bit Packing:

a. Tape slip when written (glazed capstan).

b. Dented capstan.

c. Vacuum and air pressure

out

of

specification.

d.

Plugged air bearing.

e'.

Improper operation

of

digital

to

analog converter (DAC).

f. Defective capstan control board.

g.

Binds in capstan motor.

55

3420

READ/WRITE SERVICE TECHNIQUES (continued)

Tape Edge Damage

Scope the outside tracks

(4

and 5

on

9-track drives) or (P and 7

on

7 -track drives)

on

the failing record. Look at the amplitude changes.

Developing the tape will show bits

that

were recorded on the tape and the tape was

damaged after it

was

written. This type

of

damage

is

usually caused

by

improper tape

handling.

Example: The tape reel has uneven wraps and the sides

of

the reel are squeezed

creasing the tape.

Read Forward

to

Backward Ratio Test (Models 3,

S,

7)

Use

this test

to

determine

if

a read/write head needs replacement.

Verify

that

the tape is tracking correctly before any head replacement because

of

the

above criteria.

Perform Field Tester Accuracy Check on 08-290 before proceeding.

1. Degauss the head (08-280) and the cleaner blade (08-390).

2.

Obtain a customer good quality representative tape and write

it

at 1600 bpi

on the unit being checked. Write it from the field tester with frequency switch set to

32.

3. Read forward

to

the middle

of

the reel

of

tape and stop tape.

4. Set the Field tester

as

follows.

ALTDIR SLOW

READ

UP/FWD DN/BKWD.

Potentiometers all the way

to

the back

of

tester. (Adjust DN/BKWD so tape has a forward creep rather than a backward creep).

5.

Sync and scope the Read card test points to determine the fwd

to

bkwd ratio.

Display three or four cycles

of

read signal and use

as

much

of

the scope display

as

possible for measurements (.2v/cm). For ease

of

recording, scope J2B13 with

another probe, this line will

go

positive when reading backwards.

6.

If

there

is

a read backward problem, and the amplitude in the backward direction

is

less than

that

of

the forward direction

by

50% on

anyone

track, or 60% on the

remaining tracks, the read/write head should be replaced.

If

head replacement

is

required, perform the removal/replacement procedure on 08-250.

S6

3420

READ/WRITE SERVICE TECHNIQUES (continued)

Read Forward/Backward Ratio Test (Tape Unit Models 4, 6, and 8)

Use

this test

to

determine

if

a read/write head needs replacement:

Verify that the tape

is

tracking correctly before any head replacement because

of

the

above criteria.

Perform Field Accuracy check on 08-315 before proceeding.

1.

Degauss the head (08-280) and the cleaner blade (08-390).

2.

Install a jumper from K2P02-M2D06. This forces 6250 mode.

3.

Obtain a customer good quality representative tape and write

it

at

6250 pbi on

the unit being checked. Write

it

from the field tester with the frequency switch

set at 64.

4. Read forward to the middle

of

the tape and remove jumper K2P02-M2D06 while

tape is moving, then stop tape.

5.

Set the Field tester

as

follows.

ALT DIRE SLOW

READ

UP/FWD DN/BKWD Potentiometers all the way to the back

of

tester.

(Adjust DN/BKWD

so

tape has a forward creep rather than a backward creep).

6. Sync and scope the Read card test points to determine the fwd

to

bkwd ratio.

Display three

Dr

four cycles

of

read signal and use

as

much

of

the scope display

as

possible for measurements (.2v/cm). For ease or recording, scope H2M08 with

another probe, this line will

go

negative when reading backwards.

7. If there is a read backward problem, and the amplitude in one direction

is

more

than double the amplitude in the opposite direction on

anyone

track, replace the

read/write head.

If

read/write head replacement

is

required, perform the removal/

replacement procedure on

08-250, do required adjustments and return

to

the map

that sent you here or

00-030.

If

replacement

is

not

required return

to

the map

that

sent you here or 00-030.

Note:

If

while making measurements, the tape gets back

to

load point, (resetting the 6250 latch) the jumper K2P02-M2D06 will have to be reinstalled while at load point and the tape read forward. This keeps the tape unit in

6250 without

forcing a

SAGC

setup on every record. Remove the jumper and continue the

test.

Each time the jumper is removed the

SAGC

may set up at a different ratio,

but

the ratio

will remain the same.

57

3420 READ/WRITE

~ERVICE

TECHNIQUES

(continued)

Phase Shift

Definition - A pulse time displacement that occurs

at

the transition from a low density

recorded signal to a higher density, or from a high density signal to a lower density.

When

recording at higher densities several problems are encountered.

As

density in-

creases the preceding and following bits (flux fields) tend

to

interfere with the middle

bit (see Figure 1). This phenomenon

is

known

as

phase shift. The resultant data trans-

ition at a change in recording density

is

shifted

to

the right or left because

of

the bit

crowding effect. This characteristic

of

PE recording

is

compensated for by detection

techniques.

"

,

\

x

Figure 1

\ /

, "

o

'0

x x

2X

Shift

58

3420 READ/WRITE SERVICE TECHNIQUES

(continued)

Phase Shift Scoping Procedure

If

you are having a high number

of

temporary write errors with

MTE

and not ENV

errors, use the following procedure

to

determine

if

the R/W head

is

causing phase

Using

a good customer tape:

1. Check the

SAGC

setup. Refer

to

the

MLM

page 5B-000 sequence 1.2 and 2A

with Figure A on page 5B-001. The

SAGC

should set up in 2

to

14 steps.

2. Loop write reliability test 3420R in 6250 mode.

Scope the phase pointers:

CD191 CD291 CD391

Card

YIM2 YIL2 YIK2

Pins

GI2,J11,112 G12, J11, 112 GI2,J11,JI2

Zone 1 Zone 2 Zone 3

Sync Points: Crosspoint cards can be used

so

that only data from the drive you are

running

OLTs on

is

displayed (ie, logic XC701 drive 0 A3Q2

DI2).

Refer to Chart L

for your machine configuration.

If

you have the entire subsystem, sync point (mark 1)

logic

BW151

Al

G3

M12 may

be

used.

If

any phase pointer goes active, in the data area, the head

is

marginal. This procedure

is

intended to find new heads"that may be marginal

but

should be used

as

a check for

existing heads. Refer to

MLM

08-250 for additional information.

Compatibility

Compatibility problems between drives can be caused

by

tracking

out

of

adjustment,

or

if

this adjustment

is

OK, the tracks are not centered on tape. Develop tape and

place it on the viewer

to

observe. The proper positioning

of

the head

to

tape relation-

ship

is

done by the Skew Plate. A special Skew Plate adjusting tool

is

necessary

to

do

this (included in the Reference Plate replacement kit,

BM

4298806 stocked

at

EPCs.

Refer

to

SA-9

and SA-l 0).

S9

READ/WRITE FAILURE ANALYSIS

The purpose

of

this procedure is

to

provide an effective way

to

determine what R/W

component is failing. The procedure is comprised

of

three major sections. Initial

checks, failure analysis and

FRU

replacement. This procedure should help

you

reduce

the number

of

components replaced before fixing

the

machine.

Initial

Checks

Check

and adjust as necessary

the

following:

•

-4

and +6 volts (see 08-570)

•

Vacuum and pressure (see

08-400,08-405)

• Tape

path

obstructions

Check

the

following components for wear

or

oxide buildup.

- Erase head

- Filler block

-

Auto

cleaner

- Tape

path

area

• Clean

the

head

• Read head card

and

write head card seating

Failure Analysis

• Sense Data -Sense can be obtained from the following areas:

- EREP Console messages

-

OLTs

The sense data can be analyzed using

the

sense analysis flowchart

in

this manual.

• OLTs - Tests

A-W

should be run using a good test tape.

If

no

failures occur use

the

customer's failing tape, also

try

another tape drive.

• Scoping - The following items should be scoped

to

determine failing components.

Stability -

Scope the analog signals

on

each track, the amplitudes should

be

con-

stant and

about

equal between tracks.

Forward

to

Backward Ratio - The analog signal amplitude

in

any

track

while read-

ing backward should

not

be

less

than

50%

of

the

signal amplitude reading forward.

_

Only replace the head

if

experiencing read backward problems.

61

READ/WRITE FAILURE ANALYSIS

(continued)

SAGe -

All

tracks should set up between 2 and 14 steps and the tracks should set

up within 3 steps

of

each other. Replace the head only

if

the track setting up wrong

is

causing errors.

Phase Errors - Phase errors are indicated by

MTE

errors without envelope checks.

Scoping

is

done in the 3803 while writing ripple data with a block length

of

2K

or larger. This procedure

is

for model 4, 6, or 8 only. Refer

to

the phase shift

scoping procedure in this manual for complete details.

Tracking

Check - Using the master skew tape scope the 4 and 5-tracks. The signals

should be equal and opposite between forward and backward. For example

if

track

4 leads track 5

by

one usec in the forward direction, track 4 should lag track 5 in

the backward direction. Note: This

is

a check.

Do

not use for adjustment. (See

MLM

08-150, 08-151, 08-160.)

Bit Positioning - Improper bit positioning can be caused by an improperly adjusted skew plate. Failures can appear

as

system abends and tape mark recognition problems.

Replacing the R/W head

will

appear

to

fix the problem for a very short time. Note:

Reference plate tool kit required. Refer to

SA

9 and

SA

10.

FRU

Replacement/Swapping

The following

FRUs are listed in the recommended replacement or swapping sequence.

If

a part does not fix the drives symptom, return the swapped part

to

the original drive.

•

MST

Logic Cards

•

Read Head Card

•

Write Head Card - Check

to

ensure that the write head card jumpering

is

correct.

• Read/Write Head -

When

a new head

is

installed for diagnostic purposes, only the

AMP

sensors need

to

be adjusted.

If

the head resolves the problem make certain

the Read/Write Adjustment procedures in the

MLM

(see 08-250) are followed.

62

READ/WRITE HEAD SERVICE HINTS

Factors

that

may indicate a failing head:

1.

Media

2.

System aborts indicating read or write failures

Tape runs

off

end

of

reel searching for a tape mark

No

block detected

on

a write or write tape mark

3. . High temporary write errors

4.

High forward

to

backward analog signal ratio

5. Many

OLT failures on test T3420F and very few errors on other tests

6. Varying analog signals

7. Making two amp sensor adjustments

of

.5

volts or greater in a short period

of

time

Factors

that

may indicate a failing head when the head

is

not failing:

1.

Low vacuum

2. Tape hitting obstructions in the tape path Erase head

Filler block Rewind plunger

(3,5,

7)

Auto cleaner

3. Defective read or write head cards

4. Voltages

out

of

adjustment

5.

Poor tracking causing tape

to

buckle

6. Marginal media

7 . Visual wear and poor forward to backward ratio

Replace only

if

failures are occurring

Factors

that

optimize head life:

1. Good tape library maintenance

2.

Proper and timely drive cleaning

3. Documenting problems

4. Good capstan tracking

5 . Replace the head last

63

3420

READ/WRITE NTF CHECKLIST

If

you have an intermittent read or write problem and can find nothing wrong with the

machine, perform the tests/checks indicated below before writing a

"No Trouble Found"

IR.

When

completing an NTF IR, try

to

give

information

as

accurately

as

possible.

Use

Major Unit Code 960 instead

of

980 whenever possible and include

as

much detail

as

necessary in the narrative. Your IRs are the performance feedback mechanism

we

use on the 3420/3803!

Read/Write Problems

Models 3, 5, 7

Most

probable causes:

1.

Read head card defective

2.

Write

head card defective

3. T-AIL2, T-A112, T-AtM2

(NRZI}'tlefective

4.

R/W

head defective

5. Erase head defective

Initial checks:

1.

Air

pressure and vacuum (see 08-400)

2.

-4

Vdc and +6 Vdc supply in tolerance (see 08-570)

3. R/W head and cleaner blade must be clean

4. Capstan tachometer timing (see

08-130)

5.

Degauss tape transport

if

problem

is

recurring

Reference

MLM

5A-000

Models

4,

6, 8

Most probable causes:

1.

Read head card defective

2. Write head card defective

3. T-AIL2, T-AIJ2, T-AIH2 cards defective

4. R/W head defective

5. Erase head defective

65

3420

READ/WRITE

NTF

CHECKLIST

(continued)

Initial checks:

1.

Air

pressure and vacuum (see

08400)

2.

-4

Vdc and

+6

Vdc power supplies in tolerance (see 08-570)

3.

R/W

head and cleaner blade must be clean (see Note 4 on SB-001)

4. Capstan tachometer timing (see 08-120)

5.

Degauss

tape transport if problem

is

recurring

Reference

MLM

SB-OOO

66

TAPE

DEVELOPING

PROCEDURE

Purpose:

Gives

CE

a way

of

visually examining information recorded

on

a section

of

magnetic tape.

Materials Needed:

• Developing solution (P/N 453522)

Procedure:

• "Low-tack" transparent tape (See Note 1.)

• Piece

of

clear plastic (such

as

old microfiche card, loose-leaf

page cover , etc)

• Felt-tip pen

• Flat surface (small table, etc) which can be moved

to

area in front

of

tape unit

• Lint-free cloth (P/N 2108930) dampened with water

• Mount failing tape, without cartridge, and read to error. This

is

done

from 3803

CE

panel (offline) or using "FRIEND" (OLT T0200A) or

customer utility such

as

"ditto,"

etc (online).

•

When

failure occurs press reset on drive and open front door.

While

holding "cartridge-present"

button

pressed, manually

bottom

tape in

right column. This shuts

off

pneumatics.

• Open vacuum door and put small mark

on

bottom

(non-oxide) side

of

tape

on

each side

of

R/W head with a felt-tip marker.

• Carefully remove enough tape

to

reach the flat surface table, etc.

• Shake the developing solution,

then

immerse

the

affected area

of

the

magnetic tape into solution.

Use

the felt-tip pen mark

to

determine suspect area. Rock tape back and forth two or three times being careful

not

to

drag

on

bottom

of

can.

• Remove tape from solution and allow liquid to evaporate while still rocking tape gently back and forth.

• Lay tape, oxide up, on the flat surface and use a small piece

of

trans-

parent tape at each end

of

developed area to hold in place.

• Tear

off

an appropriate length

of

transparent tape and carefully press

it onto the developed tape. Try

to

avoid air bubbles, etc.

• Gently lift the transparent tape back

off

(peel it at an angle

to

avoid

damage) and

phice

on

the clear plastic.

• The plastic with developed image may now be viewed directly or under the microfiche viewer. Since the microfiche viewer magnifies X30 be sure

to

divide any measured 'distance

by

30.

67

TAPE DEVELOPING PROCEDURE

(continued)

• Clean the magnetic tape thoroughly using the cloth dampened with water. Allow

it

to

air dry before rewinding and returning tape

to

cus-

tomer for his cleaning procedure .

.

CAUTIO~:

Any foreign material left

on

the tape

will

damage

the

drives themselves.

Conclusions:

Some

of

the more common problems which will be detected

by

tape devel-

oping are:

a. Partially erased records before an ERG. Usually caused

by

a glazed

capstan. b. Noise in gap (defective erase head, etc). c.

Short gaps (indication

of

tape motion problem)

d. Damaged tape (oxide voids, etc).

See

the following examples.

Note 1: The use

of

any other than "low-tack" transparent tape is discouraged as

it

may

remove oxide or leave adhesive

on

tape.

68

DEVELOPED TAPE SAMPLES

Here are some tips which may be helpful in analyzing the failure

on

a developed tape:

• Distance Relationships:

~

.15"

1.18"----

..

• Erase Gap (ERG) Distances:

Density

6250

1600

800

7-Track

• Interblock Gap Size:

Density

6250

1600

800

7-Track

Developed Tape Examples

~

!--

__

To BOT

t

Data Block

Single

Successive

ERG

ERGs

3.75"

3.45"

4.2"

3.6"

4.2"

3.6"

4.5"

3.75"

Nominal Minimum (Inches) (Inches)

.3

--

.6 .5 .6 .5 .75

.68

Good Data

at

1600 bpi

~.6"~

Good Gap

69

DEVELOPED

TAPE

SAMPLES

(continued)

Good Data at 6250 bpi

.3"

Good

Gap

To

.....

~~-BOT

Tape cinch/tape crease (1600 bpi) caused

by

loose wraps

on

tape

reel.

~.6"~

To

"""--BOT

Good

Gap

t

Area

A

ERG

Performed

• Drive was writing when "cinched" tape (small Z-folds) area appeared (area A).

• Prior

to

performing an erase gap

the

software tried

to

back tape up

to

last interblock

gap

but

stopped in creased area instead (thought

it

was the gap).

• From there a normal ERG command was executed and tape unit logged one temporary write error and continued normally.

.•

Since damaged area was not completely erased

by

erase gap a permanent read error

then occurred when tape

was

read.

70

3420

RD/WR DATA

FLOW

~~~;

....

0

1

Tape

2

Unit

3

Connector

Interface

4

AIN4

Connector

5

6

7

Read

and

Write Data

Flow

Within 3420

-

Models

4,6,8

Only -

(See

MLM

58·100 For Details)

0

Read

3

Connector

Card

4

AIN3

5

6

Write

Data

Flow

AIK6

AIJ2

Read

Data

Flow

AIL2

71

Connector

AIN2

Connector AIT3

R/W

Head

Layout

(Models

4,6,8

Only)

L

Mounting Plate

4

0

0 0

t=

0

6

0 0

0

§

0

0 0

t:o

0

1

0

0 0

a;

0

2

0

0 0

:r:

0

en

p 0 0

0

en

0

3

0

0 0 u

0

7

0

E

0

5

0 0

0

E

0

1=

0

0 0

0

Read

Section Wnte Section

4 6 0

1 2

P

3

7

5

Note:

The

center tap

J

is

the middle pin

on

eacli track.

Tape Unit Interface

Connector

3420

RD/WR

DATA

FLOW

(continued)

Tape

~~~~.....

~~~~face

Connector

,

Connector AIN4

Read

Section

9 Track

AIK4

Write Section

Write

Data

Flow

AIK2 NRZI Write Deskew (NRZI

Only)

AIJ2

The center tap

~

is

the middle pin

---

on

each

track.

Read

Pata Flow

~~~ectQr

1----4----------.;

AIL2

Read

and

Write

Data Flow Within 3420

- Models 3, 5, 7 Only (See

MLM 5A·100

or

PF

5·100

for

Details.)

AIM2 NRZI Read Deskew (NRZI

Only)

72

Connector AITJ

7T

k

-rae

Mounting Plate

fOJ

2 0 0

3 0 0

4 0 0 5 0 0 6 0 0

7 0 0

Read Section

Connector AIN2

~D'

~

~ : ~

~

0 0 0 4

(J) 0 0 9 5

o 0 0 0 6

E 0 0 0 7

~

WnteSectlon

Tape

Unit

Interface

Connector

To 3803

3420

TAPE MOTION SERVICE TECHNIQUES

Consider performing the following tests

if

you are experiencing intermittent 3420

failures relating

to

tape motion. The symptoms should first

be

analyzed using

MLM/

Pathfinder. \

Some

of

the more common symptoms associated with these service techniques are:

Symptom

Tape

Slip Partially Erased Records Permanent R/W Errors

High No.

of

Temp

R/W

Errors

Dropping Ready

No

Tape Motion

Dumping Tape

Glazed

Capstan Cleaning

Possible Cause

Glazed Capstan I

Glazed Capstan Also

see

3420 R/W

Glazed

Capstan Service Techniques

Glazed

Capstan

Leaky Transfer

Valve

or Column Vacuum

Door Open Capstan Motor Segment Open Capstan

Motor Segment

This procedure

is

performed only

if

glaze cannot be removed by normal cleaning.

CAUTION: This procedure,

if

not done properly and with extreme care, can

shorten

the

life

of

(or damage) the capstan.

If

the capstan edges are

rounded or flat spots are created, tracking adjustments will not be

possible.

Verify

that

this procedure

is

necessary:

1. Perform

Capstan Cleaning-Normal Procedure (see 85-004

if

necessary).

2. Perform

T3420W OLT diagnostic test.

• Run OLT T3420W to determine the size

of

interblock gaps.

[0.301 inches

is

nominal for models 4/6/8 and 0.600 inches

in nominal for models 3/5/7.]

73

3420

TAPE MOTION SERVICE TECHNIQUES

(continued)

3. Check diagnostic printouts for signs

of

variance.

• Gap sizes exceed limits specified in OLT.

If

the tape

is

varying,

the

glazed capstan cleaning procedure may be necessary.

Proceed as follows: (Refer to "Tape Slipping" under 3420 Read/Write

Service Techniques.)

a. Assemble an abrasive tool using

600 grit paper

IBM

460107 attached to

a six-inch steel rule with a double back adhesive tape such

as

3M

Y-9122* or

4282*. You may also use rubber cement or printer carriage tape glue.

b.

Remove

the

left threading channel. Place the steel rule with 600 grit paper

squarely

on

the capstan and

then

just break the glaze

on

the capstan with the

abrasive tool while rotating the capstan

by

hand.

The intent

is

not

to

remove the glaze with the tool

but

to

break through the

coating

to

allow the tape cleaning solution

to

soak under it.

c. Moisten

cotton

swabs with tape cleaner and scrub the capstan rubber

thoroughly, until the capstan attains a dull rubber finish.

d. Follow

up

with a lint-free cloth moistened with tape cleaner to remove all

traces

of

the

cotton

swab.

e.

Verify

the

effectiveness

of

your cleaning

by

repeating the T3420W OLT

test.

f. Repeat the cleaning operation only

if

step e shows IBG variance.

g.

Capstan dynamic alignment (trackip.g) must now be checked.

Capstan Motor Test

Unplug the capstan

motor

from the capstan board and measure across the two wires

going

to

the

motor

with an ohmmeter. Rotate the capstan slowly

by

hand while watch-

ing ohmmeter. The meter will deflect some

but

should never

go

to

an open condition

(open armature segment).

If

an open condition occurs the capstan motor should be re-

placed.

Note: In the pneumatics portion

of

the drive verify normal pressure and vacuum ad-

justments and checks per

MLM

08-400 before 'performing the following tests.

Column Vacuum Leakage Test

If

you suspect a column vacuum leak the following procedure

is

a good way

to

check

column vacuum level:

- Take drive offline and install tape motion tester.

*Trademark

of

the

3M

Company

74

3420

TAPE MOTION SERVICE TECHNIQUES

(continued)

- With drive unloaded, disconnect tubing

to

L3

or R3 vacuum switch.

-

Use a "Tee"

(P/N 1767025) to insert vacuum gauge (P/N 5495384) in the line.

- Reconnect tubing

to

L3

or R3

then

load tape and read gauge. Vacuum level should

be:

Model

Vacuum

3,4,5,6

21±3"

7 27±3"

8 31±2"

-

Move

tape forward and verify

that

vacuum level remains within tolerance.

- Move tape backward and verify vacuum level.

-

If

vacuum levels read low

on

these tests, clean column-to-glass mating surfaces and

check column glass adjustment.

Cracked Pressure Hoses

When analyzing any problem relating

to

pneumatics check for cracked pressure hoses.

The hose between pump and filter should be closely examined.

If

a hose

is

found

to

be

cracked replace it. Do

not

cut the hose back because it will soon crack again.

Transfer Valve Leakage Test

1. Cover the stubby column ports

with

masking tape.

See

Figure 1. Do

not

let the

tape overlap the stubby bars.

2. Place an 8-inch piece

of

magnetic tape in

the

bottom

of

the

right vacuum column

to

prevent vacuum from entering

the

column.

3.

Cut a 12-inch piece

of

magnetic tape and lay it over the left reel tach just below

the

read/write head. Ensure that

the

tape loop

is

approximately in line

with

the

bottom

of

the

capstan. See Figure 1. Bypass

the

door interlock.

4.

With no tape

on

the

right reel, press LOAD REWIND.

If

the

tape strip

is

pulled into-

the

left column before load check occurs, there

is

sufficient leakage

to

cause inter-

mittent

problems and

the

transfer valve must

be

replaced. Repeat

the

test several

times

to

ensure

that

the

valve

is

bad.

5. Remove

the

masking tape from

the

stubby column ports and clean 'the area

thoroughly with a cloth dampened with tape cleaner. Remove

the

magnetic tape

from

the

right and left vacuum columns.

7S

3420

TAPE

MOTION

SERVICE

TECHNIQUES

(continued)

6.

If 3420 Drops Ready:

, Analyze

Sense

or

Scope Error Latches

to

Find

Reason

Error Description

Fiber Optic Lamp

Failure

Tape

Bottom

or

Pull

Out

of

Left

Column*

Tape

Bottom

or

Pull

Out

of

Right

Column*

Reset

Button

or

Door Interlock

Air

Bearing

Pressure

or

Right

Reel

Hub Failure

OV

/UV

(Power

Check)

or

No

Cooling

Air

to

Capstan Board

Power-On

Reset

Safety Bail

Reset

NOTE

Drive

Error

Latches

Error

(See

Note)

Sense

Probable FRUs

+

At

S07 (Note Latched)

+

At

U02

Byte 7 •

Optic

Lamp

Bit

0 •

AlD2

Byte 7 Bit 1

• L4 Vac Switch

•

L3 Vac Switch

•

Left

Reel

Board

• Capstan Tach

+

At

U05 Byte 7 •

R4

Vac Switch

+

At

S03

+

At

S04

-

At

S02

+

At

M05 (Not Latched)

Bit

2 • Right

Reel

Board

• Capstan Tach

Byte 7

•

Reset

Button

Bit 3 • Door

Inlk

Switch

•

TA1C2

•

AB3F2

•

AA2D2

Byte 7 • Leaking File Bit 6 Hub

•

Air

Bearing or

Hub

Switch

Byte 18 • Check Voltages Bit 0 •

Dirty

Filter

•

Defective Cooling

Fan

• Check Cooling Air

Sensor

• A1C2

•

A1H2

•

Fuse

Detect

Card

Models 3,5,7

+

At

E2B09

(Not

Latched)

Models 3,5,7

• A1C2

•

Al

E2

Models

4,6,8

+

At

D4B09

(Not

Latched)

Models

4,6,8

•

A1K2

•

A1D4

• Drive error latches

are

on

following

card:

*Vacuum

switches

are

high-failure items.

Mod

3,

5,

7 - H2

Mod

4, 6, 8 - M2

• Voltage Levels are:

+

is

- .85

-

is

-1.85

76

Further Analysis Notes

See

Logic

FTl14

Go

To

3A-ll0

or

3B-ll0

Could

Be

Caused

By

OV

/UV

Detection

or Capstan Board Cooling Sensor.

See

Byte 18

Bit

0 Below.

Could

Be

Caused

By

Operator.

See

Logic

t-----------1

FTl14

Go

To

lA-OOO

or

1

B-OOO

If

A Solid Failure Tape

Will

Not

Dump

Into

Cols on Load.

These

Errors

Cause

Reel

Board

EPO

Relays

to Drop (Loss

of

Motor

Control)'

Tape

Bottom

Will Then Drop Ready

See

Logic

These

Are Not Normal

FTl12

Drop Ready Conditions.

See

Logic

FT283

However,

Intermittent

Failure May Show

as

a

Drop Ready.

3420 TAPE MOTION

NTF

CHECKLIST

Perform these checks precisely

as

described in

MLM.

Check, adjust

if

necessary:

• BOT/EOT (08-580)

•

Capstan Tachometer Adjustment (08-120 or 08-130)

•

Pneumatics (08-400 [all] and

08420)

Reference

MLM

START 1.

77

3420

TAPE MOTION

Pneumatic System with

Thread Status Active

Pressure

Sensing Switch

Scope

Points

'Ground = Pressure

Good

-4vdc = Pressure

Bad

Air

Bearing Model

Reel

Latch

Pressu

re

t

Pressu

re

E2M03

E2J02

D4J02

pr"l

mp

From Cooling Distribution Box

79

File Protect Indicate Switch

Automatic

Latch

Upper Restraint (Cartridge

Pressure)

Lower Restraint

(Threading Chute)

Left

Threadi

ng

Channel (Upper)

Right Threading Channel (Upper)

Cleaner Blade

Capstan

Motor

Right Threading

~~~

Channel (Lower)

Transfer

Valve Assembly

(Actuated

for

Threading)

Left

Reel

Hub

l~i~jiili~iiiiIil

Pressure

1::'::':::,:1

Vacuum

Model 8 Only

Vac Switch Layout

is

Typical

But May

Not

Be

the

Same

on

Your

Machine

Vacuum

Columns

Column

Vacuum Switch

Scope Points

tor Adjust-

ment Model

8 Only

Ground = Tape Above Switch

-4vdc

= Tape Below Switch

L1

B2S02

R1

B2508

L2

B2S03

R2

B2U09

L3 B2U04

R3

B2S09

L4 C2P09

R4

C2M09

} Refer

to

MLM

08-450

3420

TAPE MOTION

(continued)

Pneumatic System with

Thread Status Inactive

Pressure

Sensing Switch

Scope Points

Ground

=

Pressure

Good

-4vdc = Pressu

re

Bad

Air

Bearing Model

Reel

Latch

Pressu

re

+

Pressu

re

E2M03

3,5,7

E2J02 D4J02

pr"lm

p

From Cooling

Distribution

Box

81

File Protect Indicate Switch

tor Adjustment Model

8 Only

Automatic Latch

Upper Restraint (Cartridge

Pressure)

Lower Restraint (Threading Chute)

Left

Threadi

ng

Channel (Upper) Right Threading

Channel (Upper)

Cleaner Blade

Capstan

Motor

Right Threading

'-----II~~

Channel (Lower)

IIIl!l!l!l!l!l!Il!l!1

Pressure

1::··1

Vacuum

Model 8 Only

Vac Switch

Layout

is

Typical

But

May

Not

Be

the

Same

on Your Machine

Column

Vacuum Switch

Scope Points

-----------------

Ground = Tape Above Switch

-4vdc

= Tape Below Switch

L1

B2S02

R1

B2S08

L2

B2S03

R2

B2U09

L3 B2U04

R3

B2S09

L4 C2P09

R4

C2M09

} Refer

to

MLM

08450

3420

POWER SERVICE TECHNIQUES

• When checking

DC

voltages use all standard safety precautions.

The +6 Vdc should be adjusted with the

3420

in write status, ready, away from

load point, and moving tape.

3420

Power Check, No File

Protect

or

Power Related Problems

After using

the

MLM

without results

on

power

type

problems, the following list will

give

some

of

the known problems in this area. With power type problems it

is

a good

idea

to

go

over the supplies checking for loose screws, fuse holders, cable connectors,

etc. Check supply levels. Vibration may help aggravate failures.

1.

Bad connector

to

power resistor panel. Shows

on

LOAD.

2. Loose screws

on

transistors

on

power interface board.

-4V

low.

3. R 67

on

fuse detect card defective.

J6

cable shorted to frame.

4. Bad solder connections

to

fuses.

5. Power check air flow bit

on,

command status reject. Loose capacitor screws.

Slip

on

connector

to

power interface board solder connection bad or rivets

loose or dirty filter.

6. Power check light glows dim.

-4V

return screws loose.

7. Power check light flashes. Phasing bad or TPl-1-2-3100se.

8. Drops vacuum. Bad solder connection O/V

U/V reference card socket.

9. Power check, load check lights flicker.

K1

relay

on

reel board points

burn,

48V

supply drops. Loose

48V

wire from C8

to

HS1

on

mounting block for CR

11

12

or loose TBl-6-7.

10. Bad connection

on

J7 socket.

11. Power check

when

drive selected. Loose wire

on

power interface board where

wire comes through board

to

transistors.

12. Rewind unload in middle

of

job.

Short from

MSC

card

to

cover.

13. Heat sink 1

on

48V

supply has loose wire.

14. Bad power interface board. No

-4V.

15. Fails

to

write, dumps tape. Bad 6V supply, or bad connection

to

fuses

on

piggy

back supply.

16. Fails

on

write operation. Bad power interface board.

17. Equipment check unload in middle

of

job. Loose fuses

on

piggy back supply,

has ripple

on

supplies.

18. Blows fuse 6 and

CP

1. Bad SCR card, SCR1,

SCRll.

19. Select light after load. Flat cable from

11

on

reel board pinched and shorting be-

tween frame and power interface board.

20. Equipment check, power check light

on

dim. Bad monitor card.

21. Bad fuse detect and EPO card.

22. Blows fuse 3

on

piggy back supply. Bad write driver card.

23. Damages tape

on

rewind. Bad reel

motor

board.

83

3420

POWER SERVICE TECHNIQUES

(continued)

24. Bad

CB

1, or loose screws on CB.

25. Defective diode board

in

4V

supply.

26. Frame ground at

-12

volts. Erase head shorted

to

frame.

27. Blows fuse

10 or 12. Loose screws

on

TB

5-1.

28. 6V high or has ripple, bad power interface board.

29. 6V varies or blows reg card, bad connection 17-7

to

17-8.

30. Reed relay on OV

/W

card.

31. Blows fuse 6,

MSC

card shorted

to

support bar.

32. Diode assembly

on

YB020.

33. F13 - PCB board.

34.

F12

- Write

PCB

board.

35.

F14

- Shorted write head card.

36. Blows write driver card and

F14.

Read write cable plugged one pin off.

37.

No

output

+ 12,

-12,

4V

or 6V. Shorted cap

Cll

on

XFMR.

38. Blows

OVjUV card. HS-l transistor

on

power interface board.

39. Load check light flashes -loose fuse 3 or F3 holder.

40. Lights flicker with vibration - suspect any fuse holder.

41.

Plus 6 volts ripple or varies

...

CRI9,

20, 21, 22

on

PC2.

42. Command reject

...

ribbon cable from

01 A Al

board smashed between frame and

pneumatics cover.

43. ID burst checks

...

loose capacitor screw in power

tub.

44. Power check, no

-4V

or +6V

output.

Transfer valve picked solid. (9XXXX series

drive) power interface board

PIN 2515544, bad solder connection at connector

number

10.

45. Intermittent channel errors (ALV hangs, ALV errors) or R/W error

count

high.

Scope 4 and 6 volt supplies for excessive ripple during failure

if

possible. Failures

are almost solid while there is ripple and

then

disappears when the ripple goes away.

84

3420

POWER

NTF

CHECKLIST

• Check that air filter

is

clean and blower

is

running smoothly.

• Check/adjust

DC

voltages (watch for excessive ripple content).

• Check for loose power supply screws

if

problem

is

recurring.

85

3420

POWER -

DC

VOLTAGES

CAUTION:

Be

sure to

use

a digital voltmeter,

PINs

453046, 453585, or equivalent,

when making adjustments and use all safety precautions.

Notes:

1. Ensure that the tape unit

is

loaded, ready, and in write status before checking or

adjusting +6 V power supply. After check or adjustment, measure the voltage at

T-Al

G2Bl1.

If

voltage exceeds +6.24 V, check the file protect circuitry for

re-

sistance.

2. The maximum allowable ripple voltage

is

24

mv

peak-to-peak measured at the

power. supply.

Models 3, 5, and 7

If

you have an unmodified power supply, check voltages at

the

following test points.

Power Supply Value

Test Point

Ground

+6v

(±O.05v)(See Note 1

and

2)

T-A1G1 E09

T-A1G2D08

-4.05v

(±O.05v)(See Note

2)

T-A1 N3D02

T-A1N3D08

-48v

(+7v,

-9v)

TB1-9

TB1-8

+12v (±1v)

TB2-1

TB1-8

-12v

(±1v)

TB2-5

TB1-8

+11v (+2v,

-1.2v)

TB3-12 TB2-4

Basic Power Supply

87

3420

POWER -DC

VOLTAGES

(continued)

If

you have a modified power supply, check voltages at the following test points.

Power Supply Value Test Point

Ground

+6v (±O.05v)(See Note 1

and

2)

T-A1G1E09 T-A1G2D08

+11v (+2v,

-1.2v)

TB2-1 TB2-4

-4.05v

(±O.05v)(See Note 2)

T-A1N3D02

T-A1N3D08

-48v

(+7v,

-9v)

TB1-9

TB1-8

+12v (+1v)

TB3-1 TB1-8

-12v

(±1v)

TB3-5 TB1-8

+30v (±O.5v) *

TB2-3 TB1-8

-12v

(±1v)*

TB2-2

TB1-8

+12v

(±1

v)

*

at

Fuse

7

TB1-8

*

Used

only

for

OV

/UV

sense.

Modified Power Supply

88

3420

POWER -DC

VOLTAGES

(continued)

Models

4,

6, and 8

If

you have an unmodified power supply, check voltages at the following

points.

Power Supply Value

Test Point Ground

+6v

(±O.1v)(See Note 2)

T-A1G2B11 T-A1G2D08

-4.05v

(±O.05v)(See Note

2)

T-A1 H1C09 T-A1G2D08

-48v

(+9v,

-9.6v)

TB1-9 TB1-8

+12v (+1.4v,

-O.9v)

TB2-1 TB2-4

-12v

(±1.4v)

TB2-5 TB2-7

+11v (+1.7v,

-1.1v)

TB3-12 TB2-4

If

you have a modified power supply, check voltages at the following

points.

Power Supply Value

Test Point Ground

+6v

(±O.1

v)(See

Note 1 )

-T-A1G2B11

T-A1G2D08

+11v (+1.7v,

-1.1v)

TB2-1

TB2-4

-4.05v

(±O.05v)(See Note

2)

T-A1H1C09 T-A1G2D08

-48v

(+9v,

-9.6v)

TB1-9

TB1-8

+12v (+1.4v,

-O.9v)

TB3-1 TB3-4

- 1

2v

'(

± 1 . 1

v)

TB3-5 TB3-7

89

3420/6250 CONVERSION TIPS

The following are some hints for field conversion.

IMPORTANT:

•

Follow the instructions in the conversion books very carefully .

• The majority

of

problems

that

occur after conversion result from cards or cables

not

seated correctly and dirty,

bent,

or recessed pins.

Conversion Kits

Recommended actions prior

to

installing conversion kit.

A. General

1.

The

EC

check list

(3420

ECA 056)

It is

of

the utmost importance

that

the

EC

checklist be correct.

If

it

isn't,

you

will get the wrong parts. Do a physical check

of

each E/C

that

is

supposed

to

have been installed.

2. The prerequisite

EjCs

must be installed

on

the machine and the machine test-

ed prior

to

installing the conversion kit.

3. RPQ, features

If

features and/or RPQs were ordered for the

3803-1,3420-3,

5, 7

they

must be installed and operational before doing the conversion.

If

features and/or RPQs were ordered for the 3803-2 configuration,

they

must be installed after the conversion is complete and operational.

40

Recommend the use

of

a Circuit Test Probe Part 453587

to

expedite verifi-

cation

that

the adds and deletes are correct.

5. Ensure

that

you

are familiar with the conversion instructions before starting.

It

is

recommended

that

you

read

them

at least once prior

to

starting the con-

versions.

6. Review ITIPs (and data bank)

to

become aware

of

problems

that

may

be

en-

countered during conversion.

7. Prior to installing logic cards and connectors make sure there are no

broken

or bent pins. Inspect for recessed or loose pins on the data cable

connectors

(channel-to-tape control unit and tape control unit-to-tape unit).

91

3420/6250

CONVERSION

TIPS

(continued)

8.

All

connectors and logic cards installed/replaced

as

called out in the conver-

sion should be

"popped"

(eg, seated, removed and re-seated) a few times

to

assure a good contact.

9. The installation

of

the tape cleaner does not eliminate the present head clean-

ing procedure. -

B.

Only the logic board and logic cards in the conversion kit have been tested on a "slave machine"; cables and jumpers have not.

C.

Double check all card plugging

to

ensure that

they

reflect the converted status

of

the machine. The exception

is

on page 0950

of

the TU Conversion book. The

original model number

of

the TU should

be

plugged, not the new model that it

was

converted to.

D.

3420 Conversion Hints

After removing

"old"

fiber optics lamp, clean the ends

of

light pipes

in

the horse-

shoe with a damp, lint-free cloth. After power has been turned on, allow the

"new"

fiber optics lamp to warm up for 20-30 minutes.

1.

Assure that the R/W card cables are connected correctly.

It

is

possible to

miss the top pins

of

the R/W card connector.

2. Before removing the R/W cable guide, observe how it

is

mounted on cable connector and reassemble it the same way when you have finished modifying the cable.

3. Remove the coating on the R/W cable connector before soldering wires

to

it.

4.

When

the tape unit interface adapter shoes are installed correctly you should

see

the silver plating.

5.

Page

0490

of

the Tape Unit Conversion

book

is

causing some confusion. The wires are connected to AEI and AE2 connectors which are located on the small board (PN 4169370) on the side opposite to where the components are mounted.

6. Assure that the vacuum column restrictors are installed properly.

7.

If

after the conversion you experience R/W problems check the auto cleaner

adjustment (page

1080). Also, assure

that

the auto cleaner

is

not

activated.

This can be checked visually

by

removing the cover

of

the R/W cards (on the

front

of

the machine). With the columns loaded and looking down towards

the head you should

see

part

of

the white ribbon used in the auto cleaner.

92

3420/6250 CONVERSION

TIPS

(continued)

8. OLT

3420L

should be

run

using the same magnetic tape

that

you

used when

you

adjusted the amplitude.

Usted

below are the major conversion efforts

that

apply to all models:

1. Replace tachometer assembly and capstan control power board.

2. Replace R/W head.

3. Replace R/W cards.

4. Add new read cable.

5. Rework write cable.

6. Replace logic board.

7. Add six new

MST cards.

8. Add new power cable.

9. Remove high-speed rewind plunger.

10. Remove inspection mirror and lamp.

11. Add tape cleaner assembly.

12. Rework write-enable circuit.

13. Rework three logic cables.

14. Rework pneumatic distribution.

15. Rework or replace power supply.

16. Rework or replace power interface (miscellaneous) board.

If

converted

to

a Model 6 or 8:

1. Replace vacuum column glass with one

that

has a resonator.

The following additional rework

is

required for conversions to Model 8:

1.

Replace the capstan motor.

2. Replace the vacuum pump.

3. Rework the pneumatic supply

if

the

drive

motor

is

not in the middle.

4. Rework the transfer valve.

5. Replace the reel motors and boards

if

converting from Model 3 or 5.

6.'

Rework the power door

if

lower glass was

not

installed.

Conversion Tips from Data Bank

3420 Reference page 0453

of

Conversion Instructions.

Do

not

remove

the

"0"

ring

type washer, placed between reference

"B"

and

"F".

What should be removed

is

about

1"

- 1

*"

long and shaped like an

"L".

3420 Erratic high-speed rewind - check resistor and cover assembly part

PIN.

For

Model 6

1845820.

93

3420/6250

CONVERSION TIPS

(continued)

3420 Conversion reel motor change - when replacing reel motors

of

different styles, a

cooling hose reducer

2513076 may be required,

as

well as different anti-

rotation screws

0438579 or

0438581.

3420

Tape crease after model change - capstan

to

stubby bar clearance

ora

pneumatic

pressure check for possible air leaks may need

to

be done.

3420 Offline tester conversion (6250), check

MLM

page 90-170.

3420

Fail

to

load, reels do not turn - booster supply board

2515544 defective.

3420 Velocity check after conversion from a Model 3 to Model 7 - resistors for

assembly

2523731 should be 1 Ohm, 1 Ohm, 2 Ohm. They were 2 Ohm,

2 Ohm, and 10 Ohm, even though the correct part number

was

stamped on the

assembly.

3420

No

read or write after conversion (to 6250). Open paddle land to AIN7D02 or

could be an open solenoid or cable.

3420 Various errors after model change - check ALD page A6106 for proper position-

ed jumpers (2 pages).

3420 Won't load (any model) reels won't turn, transfer

valve

or KI won't pick,

but

the pneumatic motor runs. Incorrectly connected cable

(El

and E2 connection)

to the piggy-back supply board attached

to

the booster supply.

Compatibility problems between drives can be caused by tracking out

of

adjustment, or

if

this adjustment

is

OK, the tracks are

not

centered on tape. Develop tape and place it

on the viewer

to

observe. The proper positioning

of

the head

to

tape relationship

is

done

by the Skew Plate. A special Skew Plate adjusting tool

is

necessary

to

do this (included

in the Reference Plate replacement kit,BM

4298806). Reference

SA

9 and

SA

10.

94

3420

PM

SCHEDULE

Code

1--......-

Location

U

R

Operation Frequency

Action

0

Door Slide

4 months

Lubricate the door slide and the stop pin with

and

Stop

IBM

#17.,

General

4 months

1.

Clean front deck and base.

Cleaning

2. Remove tape cleaner block and clean with tape cleaner.

3. Remove air bearing (D-bearing) next

to

EaT/BOT

block and clean. Inspect guide

behind bearing and replace

if

grooved.

4.

Clean NRZI guides.

5.

Clean

EaT/BOT

channel mirror.

6.

Clean the fiber optic lamp.

Use

a tissue

lightly moistened with water.

CAUTION:

Allow lamp

to

cool before

cleaning.

Remove the manifuld and fiber bundles

to provide access to the lamp. Replace the lamp (08-620)

if

it

is

not

clear. Note: Cleaning or

replacement

of

the fiber optic lamp requires

the readjustment

of

the

EaT/BOT

and capstan

squaring.

Capstan 4 months Check and adjust Capstan Squaring.

See 08-120

Tach

or

08-130. Ensure capstan

is

free from dents

Squaring

and does

not

bind.

Circuit

Capstan

4 months Check and adjust Capstan Tracking. See

Tracking

08-000.

EaT/BOT

4 months Check and adjust EaT/BOT. See 08-580.

95

3420

PM

SCHEDULE

(continued)

Code

r--r--

Location

U

R

Operation Frequency Action

File

Protect 4 months

1. Push plunger in, check for binds.

Pin 2. Check that plunger extends in front

of

the

right hub flange.

3. Replace unit

if

any checks product unsatis-

factory results.

Power 4 months Check for the correct operation

of

the power

Window window safety bail.

If

incorrect, tighten the

Safety

Bail

setscrew in the safety bail terminator, and adjust the safety bail switch assembly (see 08-000).

2

Parts 12 months Order one

of

the following

B/Ms

for required

Replace-

parts.

ment

-

B/M

8492273 Puralator type filter

-

B/M

8492274 Cuno type filter

Tape

12 months Replace the tape cleaner block. Supplied with

Cleaner

parts replacement B/M.

Block

Pneumatic 12 months Check pneumatic supply belts. Supply Belts

Input 12 months Replace

filter element

of

the pressure pump

Filter input filter. Supplied with parts replacement

B/M.· Check for Puralator or Cuno type.

Cooling 12 months Clean cooling air filter or replace

as

necessary.

Filter

Air

12 months 1. Remove bearings.

Bearing

2. Brush each bearing

to

remove oxide deposits.

Cleaning 3. Install new decorative covers on air bearing.

Supplied with parts replacement

B/M.

4. Check pressure (see label).

DC

12 months Check the dc voltages. (08-570)

Voltage

96

IBM 3420, 3803 Reference Manual

Specifications and Main Features

Frequently Asked Questions

User Manual