1 Press retaining clips out
2 Push SIMM down and pull out
DEC00153
1 Disconnect power cord
2 Remove screw securing power on/off cable from chassis
3 Remove two screws securing power supply to chassis
4 Remove four screws securing power supply to rear panel
5 Remove power supply from computer
Removing the CPU
1 Disconnect power cord
2 Unlock and remove outside cover
3 Remove CPU
4 Install CPU
5 Set appropriate jumpers
d i g i t a l
FRU Removals
5
Page 2
DECpc LPv/LPv
Pin 1
DEC00144-3
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Service Guide
FRU Removals3 of 5
ER-740WW-SV.A01
Removing the 5¼-Inch FDD
1 Remove two retaining screws from each side of
bottom bay
2 Remove FDD from bay
DEC00082-3
Removing Cache and Tag SRAMs
1 Use suitable device puller and gently
remove SRAM chips from sockets
2 Be especially careful not to bend or
break pins
Removing the Mounting Adapter from
the FDD
1 Remove two retaining screws from bottom
and remove adapter
FRU Removals
4
DEC00079
Removing Real-Time Clock (RTC)
1 Use device puller and gently remove RTC
from socket
Pin 1
DEC00144-2
Page 3
DECpc LPv/LPv
DEC00081-3
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Service Guide
FRU Removals2 of 5
Removing the Mounting Adapter
ER-740WW-SV.A01
1 Remove one retaining screw
2 Remove mounting adapter from
chassis
NOTE: Mounting bracket is required
when installing a 3 1/2 inch device in
the lower 5 1/4 inch drive bay.
Removing Filler Panels
1 Place screwdriver through hole at side
2 Release plastic locking tabs
3 Remove both filler panels
Removing the 3½-Inch FDD
1 From top bay, remove two retaining screws
from each side
2 Remove FDD from bay
3 From bottom bay, remove two retaining
screws securing mounting adapter to chassis
4 Remove FDD from bay with filler panel
DEC00078-2
DEC00076-2
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DEC00080
FRU Removals
3
Page 4
DECpc LPv/LPv
DEC00092-3
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Service Guide
FRU Removals1 of 5
ER-740WW-SV.A01
Unlocking and Removing
the Outside Cover
1 Unlock outside cover
2 Remove two retaining screws
at each side
3 Slide cover toward rear until it
clears bezel
Removing Expansion Boards
1 Remove screw
2 Gently pull board outward
Removing Internal Mounting Tray
1 Loosen four retaining screws
2 Lift out of chassis
FRU Removals
2
DEC00118-2
DEC00119-2
Removing IDE Hard Disk Drive
from Mounting Tray
1 Removing four mounting screws
2 Pull drive from mounting tray
DEC00086
Page 5
DECpc LPv/LPv
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Service Guide
System Description1 of 1
ER-740WW-SV.A01
DECpc LPv/LPv
Main Logic Board
CPUIntel i486
Clock Speed25 MHz SX, 33 MHz SX,
ROM BIOS128 KB
Cache, internal8 KB
Cache, secondaryDirect-mapped, write-back,
J23, pins 1 and 2 jumpered*
J23, pins 2 and 3 jumpered
J28, open*
J28, jumpered
J29, open*
J29, jumpered
J19, open
J20, open
J19, open
J20, open
J19, open*
J20, jumpered*
J19, jumpered
J20, jumpered
Jumpers
8
* Factory setting
Page 7
DECpc LPv/LPv
Jumpers1 of 3
Main Logic Board Jumper Locations
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Service Guide
1
23
J28
J29
ER-740WW-SV.A01
J12
J11J10
Jumpers are shown with factory settings.
d i g i t a l
J9
J25
J6
J4
J3
J23
J7
J20
J19
J18
DEC00143-2
Jumpers
7
Page 8
DECpc LPv/LPv
DEC00143-4
Power
Connectors
Hard Disk
Cable Connector
Diskette Drive
Cable Connector
Mouse
Connector
Keyboard
Connector
Mounting
Holes (4)
Front Panel
Indicators
Expansion
Board
Riser
Card
Slot
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Service Guide
FRU Removals5 of 5
Removing the Main Logic Board
1 Disconnect all cables
2 Remove expansion board riser card
3 Remove mounting screws and lift main logic board from computer
ER-740WW-SV.A01
FRU Removals
6
Page 9
DECpc LPv/LPv
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Service Guide
Rear Panel Connectors3 of 3
Serial Port Connector
ER-740WW-SV.A01
The serial port is a 9-pin,
D-shell male connector
Supported baud rates are 300,
1200, 2400, 4800, 9600,
19 200, and 38 400. An asterisk (*)
after a signal name indicates an
active low signal state. For example, RXD*.
15
69
DEC00157
DB9SignalFunction
1DCDData Carrier Detect
2RXD*Receive Data
3TXDTransmit Data
4DTR*Data Terminal Ready
5GNDSignal Ground
6DSRData Set Ready
7RTS*Request To Send
8CTSClear To Send
9RINGRing Indicator
Rear Panel Connectors
12
Page 10
DECpc LPv/LPv
DEC00156
13
1
2514
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Service Guide
Rear Panel Connectors2 of 3
Parallel Port Connector
ER-740WW-SV.A01
The parallel port connector provides
an interface for a parallel printer or
other parallel device. An asterisk(*)
after a signal name indicates an
active low signal state. For example,
STB-R*.
DB25 PinSignalFunction
1STB-R*Strobe
2PRTD0Printer data bit 0
3PRTD1Printer data bit 1
4PRTD2Printer data bit 2
5PRTD3Printer data bit 3
6PRTD4Printer data bit 4
7PRTD5Printer data bit 5
8PRTD6Printer data bit 6
9PRTD7Printer data bit 7
10ACK*Acknowledge
11BUSYBusy
12PEPaper end
13SLCTSelect
14AUTOFDXT*Autofeed
15ERR*Error
16INIT*Initialize printer
17SLCTIN*Select
18 to 25GNDGround
Rear Panel Connectors
11
Page 11
DECpc LPv/LPv
6
51
10
1511
DEC00154
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Service Guide
Rear Panel Connectors1 of 3
VGA Connector
ER-740WW-SV.A01
The VGA connector is an industry
standard, 15-pin, D-type, male connector
PinFunction
1Red video
2Green video
3Blue video
4MS2
5Digital ground
6Red return (ground)
7Green return (ground)
8Blue return (ground)
9No connection
10Digital ground
11MS0
12MS1
13Horizontal sync
14Vertical sync
Rear Panel Connectors
10
Keyboard and Mouse
Connectors
The keyboard and mouse connectors
are each 6-pin, mini-DIN connectors
Intel is a trademark of Intel Corporation.
SIMM is a trademark of Wang Laboratories.
QAPlus is a trademark of DiagSoft.
PS/2 is a trademark of International Business
Machines Corporation.
Logistics and Support
21
Page 14
DECpc LPv/LPv
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Service Guide
Troubleshooting8 of 8
QAPLUS Error Messages (continued)
ComponentMessagesSolution
Floppy driveFloppy Drives FailedCheck connections
ER-740WW-SV.A01
Replace drive
Battery/ClockClock Stopped
Invalid Date
RTC Interrupt Failed
CMOSCMOS Clock Test FailedChange time from Setup
Serial portCOM port failed
Serial Chip Error
Serial Compare Error
Serial Timeout Error
Onboard video
circuitry
Video Failed
Error in Video Buffer
Run Setup
Replace battery/clock
menu in QAPLUS
Check COM device
Check connections
Replace COM device
Replace main logic board
Troubleshooting
20
Page 15
DECpc LPv/LPv
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Service Guide
Troubleshooting7 of 8
QAPLUS Advanced Diagnostics
To:
* Receive System Information, select SysInfo menu from the main menu.
* Locate bad chips and run mouse and keyboard tests, select Interact menu.
* Edit CMOS select Setup menu.
* Run tests on components, select Testing menu.
Default testing is No Pause on Errors/Single Pass/No Peripherals/No Error
Logging/Test All Components.
To change default, select settings under the Testing menu
QAPLUS Error Messages
ComponentMessagesSolution
ER-740WW-SV.A01
before
running tests.
CPUArithmetic Function Failed
General Functions failed
Exception Interrupt in Protected Mode
Refresh Failure
Logic Functions Failed
Hard diskButterfly Cylinder Access Test Failed
Cylinder 0 Errors
Random Cylinder Access Failed
Linear Cylinder Access Failed
Hard drive/controllerController Diagnostic Test FAiled
Questionable Controller Card
Hard drives failed
Floppy disketteMedia Mismatch
Drive Not Ready
Unformatted Media
Write Protected Media
Reset CPU
Replace CPU
Low-level format hard disk
Replace disk
Run Setup
Check connections
Reset controller
Replace controller
Replace disk
Use known good diskette
Check size and density of
diskette
Close drive door
Remove write protection
Format diskette
d i g i t a l
Troubleshooting
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Page 16
DECpc LPv/LPv
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Service Guide
Troubleshooting6 of 8
DMA Channel Assignment
ChannelControllerFunction
01Refresh
11Not used
21Diskette controller
31ECP (optional)
42Cascade DMA
1-1-3CMOS Write/Read test or failure02h
1-1-4ROM Checksum test or failure03h
1-2-1Interval timer test or failure04h
1-2-2DMA initialization or failure05h
1-2-3DMA page register write/read test or failure06h
1-3-1RAM refresh verification or failure08h
1-3-31st 64 KB RAM chip or data line failure0Ah
1-3-41st 64 KB RAM odd/even logic failure0Bh
1-4-11st 64 KB RAM address line failure0Ch
1-4-21st 64 KB RAM parity test failure0Dh
2-1-1Bit 0 1st 64 KB RAM failure10h
2-1-2Bit 1 1st 64 KB RAM failure11h
2-1-3Bit 2 1st 64 KB RAM failure12h
2-1-4Bit 3 1st 64 KB RAM failure13h
2-2-1Bit 4 1st 64 KB RAM failure14h
Beep
Code
Error MessagePort
80h
3-1-1Slave DMA register test or failure20h
3-1-2Master DMA register test or failure21h
3-1-3Master interrupt mask register test or failure22h
3-1-4Slave interrupt mask register test or failure23h
3-2-4Keyboard/mouse controller test or failure27h
4-2-1Timer tick interrupt test or failure34h
4-2-2Shutdown test or failure35h
4-2-3Gate A20 failure36h
4-2-4Unexpected interrupt in protected mode37h
4-3-1RAM test or failure (above 0FFFFh)38h
4-3-3Interval timer 2 test or failure3Ah
4-3-4Time-of-day clock test or failure3Bh
4-4-1Serial port test or failure3Ch
4-4-2Parallel port test or failure3Dh