Lexicon LEX300REPProzedur User Manual

3 Oak Park Bedford, MA 01730
Tel [phone], Fax [phone]
email: [e-mail]

M300 REPAIR PROCEDURE

The purpose of this document is to assist authorized Lexicon Service technicians in
repairing and updating returned units to current manufacturing standards. This and
it’s associated procedures are the factory repair standard and are recommended to
authorized distributor service centers. This procedure is to be used in conjunction the
product service manual, technical bulletins and with standard performance verification,
troubleshooting and QC procedures.

nature and should be treated by Lexicon and it's representatives as such.

Part 1. Mandatory repairs ALL RETURNS

1. Confirm complaint(s) and repair.

2. Clean all jacks with nonresidue spray.

3. Seat all components in sockets.

4. Inspect for any cracked or otherwise damaged components.

5. Clean unit inside and out.

6. Check all cables as to condition and proper connection.

7. Check for all ECOs based on revision of PCB's. Incorporated as needed at time
of repair.

8. ECO 910314-01 Check installation of R106 per ECO.

9. ECO 910410-02 ANALOG BD, REV 1-4; Add two (2) daughter boards to the
Analog Bd, to correct differential output line driver signal balance ratio. ONLY if
customer registers a complaint.

10. ECO 911205-00 AES INTERFACE BD Rev 1 & 2;

- Release V1.10 firmware to implement fix for slave recovery from missing or
intermittent external digital input (external clock).

- Change gain on RCA SPDIF digital input receiver to improve noise immunity to
corrupt signals received through RCS SPDIF 1/P.

11. ECO 911210-00 Front Panel, change the "RUN" button to read "SETUP SELECT"
to avoid confusion by the user. Marketing requested modification.

12. ECO 920117-01 ANALOG MAIN BD, Rev 4, check for removal of OP signal
ground per ECO.

13. ECO 901227-00 Add RTV to add support to battery to prevent from breaking in
the field on HOST Bd.

14. ECO 921118-00 Install Version 1.11 at time of repair or when customer calls
call with a problem of recording through the digital interface. This is bug in
version 1.10 only.

15. ECO 930616-01 PS Heatsink Assembly - add washers (2 - lock split #6, P/N
644-01740) to +5V digital regulator mounting (torque 6-8 in/lbs).

16. ECO 931203-00 V3.50 UPGRADE - all Consigment, New and R/E Stock;

CUSTOMER UNITS ONLY IF PURCHASED! IF CUSTOMER UNIT HAS V3.??
(OTHER THAN 3.5) INSTALL V3.5!

17. ECO940105-00 Corrects layout - BAT1 positive terminal too close to a via
carrying D2 signal. New Rev-7 PCB. All Rev 6 boards should be inspected
and reworked: using needle nose pliers, carefully bend positive terminal lead
away from circuit via. Shock Test failures resulting in BUSS ERROR have been
encountered.

18. ECO940411-00 Changes AES termination - AES Bd: Delete 202-07779 1/2W
240ohm resistor at R7 and Add 202-08190 1/4W 110ohm

Some of the information contained herein may be proprietary in

M300 Repair Procedure; REV 4.4 July 16, 2001
1

3 Oak Park Bedford, MA 01730
Tel [phone], Fax [phone]
email: [e-mail]

M300 REPAIR PROCEDURE

Part 2. Optional repairs AS NEEDED

1. ECO 930412-00 Change resistor R7 on PS Bd from 3k ohm (202-00537) to 4.99k

ohm (203-00464) change pfail circuit so pfail/ happens before +5v starts losing
regulation.

2. ECO 930426-00 Analog Bd, all Revs. Change resistors at locations R57 and R82
from470k ohm (202-00579) to 200k ohm (202-00576) to provide more offset
adjust range on calibration of PCM56

3. ECO 971218-00 USE LEXICHIP 2A ONLY IN M300/L. NEW PART NUMBER

CREATED, 330-12589

4. ECO 990402-00 Obsolete part replacement; Lexicon P/N 430-02285

LED,RED,.118DIA; Locations: Host Bd. D2, 3 [MFR P/N PR39325 - Stanley: obsolete].
Use Lexicon P/N 430-13706 LED,RED,.118 DIA,3MCD Note: any existing Lexicon stock of

P/N 430-02285 reserved for use on M41, M42 and M2400 service.

5. ECO 990401-00 The following Manufacturer has been deleted from the approved

vendor list for Lexicon P/N 355-07542 DAC,AD7628,CMOS,2X8BIT,MDAC: Maxim
MX7628KN. Note: the Maxim part does not always work in the M300 & M300L due to
a timing violation between A/BSEL and LINWR/, RINWR/, LOUTWR and ROUTWR/
signals. Only Analog Devices parts are used in new production and should be used
service failure replacements.

6. EC0 000808-01 FP Processor Board - correct encoder resolution with 36-postion

encoder (P/N 452-09762): Replace U2, 350-08574 IC,ROM,27128,M300 FP,V2.01 with
350-08059 IC,ROM,27128,M300 FP,V1.0. Note: P/N 350-08574 should be used with
any M300 FP with encoder P/N 452-04233 SW,RTY,INC ENCODER,50 POS. P/N 350­08059 may be used with encoder P/N 452-09762 SW,RTY,ENCODER,36 POS,VERT
MNT. Note, first serial number with 36 position encoder and V1.00 ROM (350-08059)
is SN: 4947. Update customer units as requested. Update all Lexicon inventory
returned to stock.

Part 3. Troubleshooting notes

1. Failing ATE due to high freq distortion in A/D portion of board while DSP Bd is

running a program, ECO 900716-00

2. Unit fails recording through the digital interface, with version 1.10 installed. Refer

to ECO 921118-00.

3. DW 930625-00 analog Devices part OP-275 added to spec for Lexicon P/N 340-

07565 Ic Linear MC33077

4. M300 ATE released for V3.00 010-08389 (ATE files) and 010-08390 (ATE

Descriptions).

5. DCR931111-06 Analog Devices OP-275 added as a second source for P/N 340-

07565 (MC33077). NOTE: MC33078 is NOT a recommended substitution - higher
voltage offsets.

6. 940105-00 Corrects layout - BAT1 positive terminal too close to a via carrying D2

signal. New Rev-7 PCB. All Rev 6 boards should be inspected and reworked: using
needle nose pliers, carefully bend positive terminal lead away from circuit via.
Shock Test failures resulting in BUSS ERROR have been encountered.

M300 Repair Procedure; REV 4.4 July 16, 2001
2

3 Oak Park Bedford, MA 01730
Tel [phone], Fax [phone]
email: [e-mail]

M300 REPAIR PROCEDURE

7. 970418-02 Alps encoder, Lexicon P/N 452-04233 SW,RTY,INC ENCODER,50 POS

discontinued. Replace with P/N 452-09762 SW,RTY,ENCODER,36 POS,VERT MNT
(Noble part).



ECO980417-00 Replace discontinued Motorola part MC68008, P/N 365­04594 with 024-12910 ADPTR BD,ASSY,68008 [Note: for spare parts sales,
023-12909 ADPTR BD,PRE-TEST,68008]. Use existing stock of P/N 365­04594 for repair of older M300/M480L. . Replacement has not been tested in
older revs but may work.

Part 4. Engineering change orders

1. 890707-00 Sub panel front change cable slot size.

2. 890724-00 Add keyboard support 702-07474.

3. 890824-01 Delete 641-06758 add 640-08061 hardware cost reduce

4. 890828-00 550-07573 changes so to fit PCM-x as well

5. 890831-00 FP Add U19,SW32 (BOM errors)

6. 890922-00 Bom change delete mem x2 add 1 meg mem x2

7. 890928-00 Demensions front panel

8. 890928-01 Drill dwg aes brd

9. 891006-00 Drill dwg host brd

10. 891011-00 Mechanical drawing changes knob, cover, bracket, support, front
panel & box.

11. 891017-00 Front panel lense changes

12. 891019-00 Chassis & Front panel B.O.M. changes

13. 891106-00 Button changes FP

14. 891117-00 HOST Rev 1; drill out feedthrough, 3 Cuts, 4 Jumper. Does not
apply to repairs, manufacturing only.

15. 891117-01 ANALOG Rev. 1 Remove jumper wire W1 2-3, etch cut.

16. 891117-02 DSP Rev. 1 Drill swage holes to .187", add kapton tape U50, add
R23 75 ohm & C66 150pf U51, add kapton tape under R23/C66.

17. 891117-03 AES interface Rev.1 move R1 to prevent shorts.

18. 891117-04 FP switch Rev. 1 Correct resistor values; R1,3,16,8,9,11,14,16.
PC board relocate Q1-4.

19. 891120-00 FP Rev. 1 Move components.

20. 891121-00 Power Supply change 440-07783 1/16AMP from fast-blow to slo­blo.

21. 891129-00 Change screw tap soft knob

22. 891201-00 Mechanical spec changes

23. 891204-00 ANALOG Rev. 1 correct schematic ferrite beads.

24. 891207-00 Revise B.O.M's Analog & Chassis.

25. 900117-01 DSP Rev.1,2 Add 74HC04 (cuts & wires on 20 pilot)

26. 900117-01-A DSP Rev.2 Add daughter board to reduce rework and possible
scrap. (not on 20 pilots)

27. 900118-01 HOST Rev.1,2 (wires & cuts on 20 pilots +)

28. 900118-01-A HOST Rev.1 Add functionality to ADI 5400 chip. Create daughter
brd. 024-08366. (20 pilot only)

M300 Repair Procedure; REV 4.4 July 16, 2001
3

3 Oak Park Bedford, MA 01730
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email: [e-mail]

M300 REPAIR PROCEDURE

29. 900118-02 Power Supply Rev.1 Prevent premature fuse blowing. Change
.25A to .5A, C8 from 47uf to 220uf.

30. 900118-02-A Correct error with F2.

31. 900207-00 Change front panel finish. (all should be same)

32. 900215-00 Analog Brd. Socket MDAC's U2,8,11,15. (20 pilots not done)3

33. 900516-00 Update graphics FP & button

34. 900320-00 HOST Rev.1,2 Improve noise immunity of PLL. Remove
U11,C21,CR2 & R14. Add Socket 520-00942 & 74AC14 330-06495 U11, 245­03868 33pf C21, 202-00506 20 ohm CR2, 202-00517 200 ohm R14, buss wire
to gnd R14,R15,C19,U14.7&8 and Q2.1.

35. 900321-02 Add assy note to glue button.

36. 900321-00 Change all buttons to black.

37. 900322-01 Mounting bracket reduce cost, change finish, use on M-300 only
& use std. aluminum extrusion.

38. 900327-00 DSP Rev.1,2,3 Add chassis gnd and resistor network to Rev.1,2.
Add R24,25,26 to BOM. REV. 1 & 2

- Make chassis gnd 620-06638 & 675-03722 install under nut on J3 closest to
U3.

- Feed lug gnd lead between rear panel and DSP and solder to J3,P2 (DSP solder
side)
Solder side

- Attach R24 202-00515 150ohm between U3.7 and U3.8.

- Attach R25 202-00543 5.1K between U3.1 and U3.8.

- Attach R26 202-00543 5.1K between U3.4 and U3.7
REV. 1, 2 & 3 component side

- Cut center etch above U44 before via

- Attach jumper from via above C65 to U44.5

39. 900327-01 FP assy. Rev.1,2 To prevent etch/pins shorts on switch panel
add washer (7) 644-06347, install kapton tape per drawing.

40. 900406-01 update shipping material from drop test

41. 900406-02 FP REV.3 revise rev.2 for keep out zones

42. 900412-01 FP REV.3 revise rev.2 move swage hole

43. 900416-00 HOST REV.4 revise rev.3 artwork for rev.4 release.

NOTE: REV.2 & REV.3 NEVER BUILT PRODUCTION

44. 900416-01 Add CLA label 740-02773, delete CSA 740-06678 and ETL 740-

06679.

45. 900416-01-A Delete 740-06680 TUV label

46. 900416-02 FP delete knob 550-07573, add 550-08253 textured.

47. 900416-03 DSP Rev.3 delete dughter brd. 024-08350, add 330-03487 (2)
U28,29, delete socket 520-00943 U28,29 and add pick rev.3

48. 900502-00 FP switch brd. blacken unused led faces with sharpie.

49. 900503-01 Shorten cable 680-07761 from 16" to 10.5"

50. 900515-00 Limit input voltage swing, add diode, 1N914 and 4148, CR31-34.

51. 900515-01-A Condition the I/P signal to CS5326 ADC

- Current limit I/P to +10mA. Worst case @ 35kHz, +22dbm.

- Change max voltage swing from 11.4Vpp per ECO 900515-00 to 10.5Vpp.

52. 900518-00 Correct error in mismatch of parts, washer,lock,split.

53. 900518-01 Change knob to correct play in knob.

54. 900522-00 Ground unused inputs and control signals on U7 (HC253) to fix
artwork error.

M300 Repair Procedure; REV 4.4 July 16, 2001
4

3 Oak Park Bedford, MA 01730
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email: [e-mail]

M300 REPAIR PROCEDURE

55. 900529-00 Add service option package.
900529-00-A To correct errors in original ECO.

56. 900619-00 Allow use of M300 bottom cover on CP-3.

57. 900621-00 Label to comply with VDE standards.

58. 900702-00 Change U24 Mem-decode GAL to accommodate 1 megabit ROMs
in ROM1 location (U22).

59. 900705-00 Change encoder, soft knob and sub front panel after initial stock
is depleted.

59A. 900705-00-A Allow deviation from BOM for FP assembly to use Rev 3 Processor

Bds #710-07458, with Rev 2 FP Switch Bds #710-07498.

59B. 900705-00-B To correct the version number displayed on power up from V1.00

to V2.00.

60. 900713-00 Correct BOM for R9 & R10 values for DSP Bd., Rev 2 and higher.

61. 900716-00 To reduce distortion at high frequencies in the A/D portion of
board while the DSP board is running a program.

62. 900716-00-A Standardize wire color.

63. 900814-00 Insure transistor on the FP Switch Bd will not touch or be bent by
the front panel when installed.

64. 900815-00 Update DSP Bd.

- Correct BOM for Rev 3 and 4 boards. (Rev 3 Bds are not being built)

- To allow MIDI thru jack to work and correct implementation of MIDI thru jumper
(W6).

65. 900822-00 Add fuse warning labels to comply with CLA.

66. 900828-01 Comply with CLA and change ROM size to accommodate s/w.

67. 900914-00 Isolate local XCLK to remove 2V reflection which exceeds the
minimum input high voltage causing arbitrary clocking of the ADI5400.

68. 900914-00-A Correct rework instructions on original ECO.

69. 901002-00 HOST Bd (Rev 1,4,5) Install C82 on solder side of PCB between
the gnd side of R28 and the cathode of CR3, as shown on page 4 of ECO.

70. 901012-02 Correct screw length in finishing kit.

71. 901023-02 Host Bd software. Correct software error in init sequence. New
Version V1.01.
901023-02-A Update Host board to V1.02 to correct assorted software errors

There are serparate BOMs for M300 and M300/S

72. 901023-00 M300 Develope new BOMs for compatibility with MINX system.

73. 901028-01 M300/S Update BOMs for compatibility with MINX.

74. 901119-00 Correct schematic errors on REV 4, DSP Boards.

75. 901126-00 Change signal name on schematic.

76. 901207-01 Software release notice for V1.02 only, obsolete upon next release.

77. 901224-00 Add silk screen to solderside of Analog board, Rev 3.

77A. 901219-00 Correct top cover problems.

78. 901227-00 To add support to battery to prevent from breaking in the field on
HOST Bd.

79. 910103-00 HOST Board Rev 5, update rev 5 boards to make compatable to
previous ECO's.

80. 910201-01 KNOB, to correct engineering error.

81. 910201-00 Top and bottom cover screw change to eliminate interference to
FP assembly, new part number 641-08796.Correct BOM error

M300 Repair Procedure; REV 4.4 July 16, 2001
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email: [e-mail]

M300 REPAIR PROCEDURE

81A. 910201-00-A Delete washer Stk # 644-06347.

82. 910207-00 Correct mechanical design errors for the manufacturing process.

83. 910227-00 Fix bottom cover fit, replace spacer part # 630-07548 with part #
630-07546.

84. 910314-01 ECO shows the proper installation of R106.

85. 910315-00 Updates drawing of DSP Board.

86. 910315-01 Update drawing for AES board.

87. 910410-02 ANALOG BD, Rev 1-4; Add two (2) daughter boards to the Analog
Bd, to correct differential output line driver signal balance ratio.

88. 910530-00 Change screw length for mounting bracket from 10-32X5/16 to
10-32X3/8, FH, PH; Stk # 640-08874.

89. 910613-00 FP screw to short, delete 641-08796 add 641-09004.

90. 911024-01 To change DC offset removal cap in output driver Circuit to meet
unblaanced frequency response test spec of +/- 0.2db @ 10Hz. On Analog
Daughter Bd for rev 1-3 Analog bd; and Analog bd rev 4. Change capacitor
value from 10uf to 47 uf.

91. 911127-00 Remove Optical cables from ship kit. The are no longer provided
with the unit.

94. 911125-00 ANALOG Bd Rev 4 and Daughter Bd Rev 0, add power supply
caps to the 2442 O/P driver on the Analog Daughter bd; add addition power
supply bypass caps to 2142 O/P driver on the Analog Bd to improve stability.
Revise Analog Bd rev 4 to improve PCB layout of U10,14 bypass caps. This
change is on production boards, none have made is to the field.

94A. 911125-00A ANALOG BD, Rev 4, (Rev 1-3 WITH DAUGHTER BD); To correct

component manufacturing and design errors.

94B. 911125-00B Analog Bd Rev3, on ECO 911125-00A the wrong capacitor was

called out. Delete part #(245-00590) on all references. Replace with part # (245-

03870) Cer Cap 150pf, 100volt .

95. 911205-00 AES INTERFACE BD Rev 1 & 2;

- Release V1.10 firmware to implement fix for slave recovery from missing or
intermittent external digital input (external clock).

- Change gain on RCA SPDIF digital input receiver to improve noise immunity to
corrupt signals received through RCS SPDIF 1/P.

96. 911210-00 Front Panel, change the "RUN" button to read "SETUP SELECT" to
avoid confusion by the user. Marketing requested modification.

97. 920117-01 ANALOG BD, Rev 4, remove left and right O/P ground from signal
ground to leliminate possible ground loops. There is no product in the field.

98. 920211-00 Chassis add ground indicator labels as identified in the ECO for
UL1419 & TUV approval.

99. 920220-00 Change length and color of ground wire #675-02852 from 4",
GRN to 4.5", GRN/YEL.

100. 920515-00 To conform to TUV certification, add switch protection bracket
and new power cord to 220V unit only in stock and all future builds.

101. 920728-00 AES Bd. Rev 3; Add missing C11 and J2 nomenclature to board.

M300 Repair Procedure; REV 4.4 July 16, 2001
6