NAD T762 User manual

1
REISSUE DATE: JULY 2008
VERSION HISTORY ............................................................................................................................. 2
PCB LAYOUT - DSP BOARD (ISSUE 8 - 10) ................................................................................... 3 - 5
PCB LAYOUT - KEYBOARD (ISSUE 8 - 10) .................................................................................... 6 - 8
SCHEMATIC DIAGRAM - DSP BOARD (ISSUE 8 - 10) ..................................................................9 - 11
SCHEMATIC DIAGRAM - KEYBOARD (ISSUE 8 - 10) ................................................................. 12 - 14
NEW DSP BOARD AND DSP SCHEMATIC (SERVICE PART REPLACEMENT) ......................... 15-16
REPLACEMENT ASSEMBLY FOR Q701 ..................................................................................... 17-18
SERVICE MANUAL
ADDENDUM

2
VERSION HISTORY
ISSUE
ISSUE 6
ISSUE 7
ISSUE 8
ISSUE 9
ISSUE 10
DESC. / PART NO.
DSP :
55-0762054-20-00
(CNC BOARD)
KEYBOARD :
55-0762003-20-00
(CNC BOARD)
DSP :
55-0762054-20-00
(TOOLED PCB)
KEYBOARD :
55-0762003-20-00
(TOOLED PCB)
DSP :
55-0762054-20-01
(TOOLED PCB)
KEYBOARD :
55-0762003-20-01
(TOOLED PCB)
DSP :
55-0762054-20-02
(TOOLED PCB)
KEYBOARD :
55-0762003-20-02
(TOOLED PCB)
DSP :
55-0762054-20-03
(TOOLED PCB)
KEYBOARD :
55-0762003-20-03
(TOOLED PCB)
CAUSE(S)
•Change FFC connector to pin
connector
•Change FFC connector to pin
connector
•Move A/D Component
• Add Coil in Digital Input
•Del Wire form Crystal to
Chassis
•Add Supply E.Cap
•Add Transistor for IR_OUT
•Add test pin
•Add missing connection of
R229.2 to C223.1
•Add test pin
•Add C.Cap C1181 for safety
issue
•Swap connection of
TRIG_OUT_2 / TRIG_OUT_3
•Add E.Cap C1182 for
eliminate Pop noise
•Delete Component of IR_OUT
•C223 Change to Axial Type
SERIAL NUMBER
R2ZT76200001-R2ZT76200400
R2ZT76200401-R2ZT76201400
R31T76201401-R31T76202198
R33T76202201-R33T76204100
R35T76214101-R35T76214600
NOTES:
The PCBs are compatible use from Issue 7 to 10. (Issue 6 is not a compatible with later ssues)
The DSP assemblies are keyboard specific. Please refer to pages 15 and 16 for jumper settings.
i
Original P/N Interim P/N Final P/N with Description
80-0907620-02-00 800-KEBD62-00 50-922-0762-90 - T762(i) KEYBOARD ASSEMBLY
80-0907620-32-00 800-LEBD62-00 50-915-0762-90 - T762(i) LED BOARD ASSEMBLY
80-0907620-42-00 800-VEBD62-00 50-920-0762-90 - T762(i) COMPOSITE VIDEO
BOARD ASSEMBLY
80-0907620-63-00 800-POBD62-00 50-924-0762-90 - T762(i) PRE-OUT BOARD ASSEMBLY
80-0907620-65-00 800-DSBD62-00
see pages 15-16 - T762(i) ORIGNAL DSP ASSEMBLY (NLA)
95-0907625-12-01 OHF-N0762S-01 50-940-1762-90 - T762AH POWER AMP MODULE W/O HS
N/A OHF-N0762I-01 50-940-0762-90 - T762(i) POWER AMP MODULE

3
PCB LAYOUT
DSP BOARD (ISSUE 8)
COPPER SIDE
COMPONENT SIDE

4
PCB LAYOUT
DSP BOARD (ISSUE 9)
COPPER SIDE
COMPONENT SIDE

5
PCB LAYOUT
DSP BOARD (ISSUE 10)
COPPER SIDE
COMPONENT SIDE

6
PCB LAYOUT
KEYBOARD (ISSUE 8)
COPPER SIDE
COMPONENT SIDE

7
PCB LAYOUT
KEYBOARD (ISSUE 9)
COPPER SIDE
COMPONENT SIDE

8
PCB LAYOUT
KEYBOARD (ISSUE 10)
COPPER SIDE
COMPONENT SIDE

9
SCHEMATIC DIAGRAM
DSP BOARD (ISSUE 8)
NOTE:
1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%.
2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 5%.

10
SCHEMATIC DIAGRAM
DSP BOARD (ISSUE 9)
NOTE:
1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%.
2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.

11
SCHEMATIC DIAGRAM
DSP BOARD (ISSUE 10)
NOTE:
1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%.
2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.

12
SCHEMATIC DIAGRAM
KEYBOARD (ISSUE 8)
NOTE:
1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%.
2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.

13
SCHEMATIC DIAGRAM
KEYBOARD (ISSUE 9)
NOTE:
1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%.
2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.

SCHEMATIC DIAGRAM
KEYBOARD (ISSUE 10)
NOTE:
1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%.
2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.

PCB LAYOUT
DSP BOARD (FINAL SERVICE PARTS VERSION)
Part Number: 50-918-0762-90 T762/T762i DSP (For ALi Keyboards,
backwards compatible via jumper option below)
Part Number: 50-918-1762-90 T762/T762i DSP (For ATMEL Keyboards,
forwards compatible via jumper option below)
COPPER SIDE (SHOWING JUMPER OPTION)
COMPONENT SIDE
15
For ALI keyboard T762 & T762i; R1251 - N.I., R1252 - R1254 - 0 ohm
For ATMEL keyboard models, R1251 - 0 ohm, R1252 - R1254 - N.I.

ALL +6dB GAIN
(NOTE 1)
(NOTE 1): 68pF used in first 100pcs T773II production, refer to HF-EN-N2773-006
NOTE 2
NOTE 2
NOTE 2
NOTE 2
(NOTE 2): For ALI keyboard T762 & T762i; R1251 - N.I., R1252 - R1254 - 0 ohm
(NOTE 2): For ATMEL keyboard models, R1251 - 0 ohm, R1252 - R1254 - N.I.
1
VD1
2DGND1
3
XMT958
4EMWR
5EMOE
6SCDI N
7SCCLK
8EMAD7
9EMAD6
10 EMAD5
11 EMAD4
12
VD2
13 DGND2
14 EMAD3
15 EMAD2
16 EMAD1
17 EMAD0
18 CS
19 SCDO UT
20 INTREQ
21 EXTMEM 22
SDATAN1
23
VD3
24 DGND3
25
SCLKN1
26
LRCLKN1
27
SDATAN2
28
SCLKN2
29
LRCLKN2
30
CLKIN
31
CLKSEL
32
FILT2
33
FILT1
34
VA
35 AGND
36 RESET
37 DD
38 DC
39
AUDATA2
40
AUDATA1
41
AUDATA0
42
LRCLK
43
SCLK
44
MCLK
U1001
CS49326-CL
C1061
0.1u
C1062
1u 50V
C1003
0.1u
C1004
1u 50V
R1001
4.7k
R1002
4.7k R1003
3.3k
R1004
3.3k
R1005
3.3k
R1006
3.3k
1DIR
2A0
3A1
4A2
5A3
6A4
7A5
8A6
9A7
10
GND
11
B7
12
B6
13
B5
14
B4
15
B3
16
B2
17
B1
18
B0
19 OE
20
VCC
U1002
74LVC245A
1DIR
2A0
3A1
4A2
5A3
6A4
7A5
8A6
9A7
10
GND
11
B7
12
B6
13
B5
14
B4
15
B3
16
B2
17
B1
18
B0
19 OE
20
VCC
U1003
74LVC245A
1SEL ECT
2A0
3B0
4
Y0
5A1
6B1
7
Y1
8
GND
9
Y2
10 B2
11 A2
12
Y3
13 B3
14 A3
15 O/P_ENABLE
16
VCC
U1004
74HC157
1
CDOUT
2
CS
3
EMPH
4RXP0
5RXNO
6
VA
7AGND
8FILT
9RST
10
RMCK
11
RERR
12 RXP1
13 RXP2
14 RXP3
15 RXP4
16
OSCLK
17
OLRCK
18
SDOU T
19
INT
20
U
21 OMCK
22 DGND 23
VD
24 H/S
25 RXP5
26 RXP6
27
CDIN
28
CCLK
U1005
CS8415A
R1007 33
R100810k
C1006
220p
C1007
0.01u
R1009
200k
C1010
0.01u
R1013
1.2k
C1012
10u
16V
1
VPP
2
A16
3
A15
4
A12
5A7
6A6
7A5
8A4
9A3
10 A2
11 A1
12 A0
13 Q0
14 Q1 15 Q2 16 VSS 17 Q3 18 Q4 19 Q5 20 Q6
21
Q7
22
E
23
A10
24
G
25
A11
26
A9
27
A8
28
A13
29
A14
30
A17
31
P
32
VCC
U1007
SST27SF020
(256K x 8)
1OE
2D0
3D1
4D2
5D3
6D4
7D5
8D6
9D7
10 GND 11
CLK
12
Q7
13
Q6
14
Q5
15
Q4
16
Q3
17
Q2
18
Q1
19
Q0
20
VCC
U1008
74LVQ574
1OE
2D0
3D1
4D2
5D3
6D4
7D5
8D6
9D7
10 GND 11
CLK
12
Q7
13
Q6
14
Q5
15
Q4
16
Q3
17
Q2
18
Q1
19
Q0
20
VCC
U1009
74LVQ574
C1017
0.1u
R1020
10k
C1018
0.1u
C1019
0.1u
C1020
3.3u 50V
C1021
3.3u 50V
R1022
10k
R1023
2.2k
C1022
3300p
3+
2-
1
U1010-A
NJM5532M
R1024
620
R1026
10k
R1027
2.2k R1028
2.2k C1024
1000p
C1025
1500p
R1030
2.2k
C1026
3300p
5+
6-
7
U1010-B
NJM5532M
R1031
620
R1033
2.2k
C1028
1000p
C1029
1500p
R1035
2.2k
C1030
3.3u 50V
C1031
3.3u 50V
R1036
10k
R1037
2.2k
C1032
3300p
3+
2-
1
U1011-A
NJM5532M
R1038
620
R1040
10k
R1041
2.2k R1042
2.2k C1034
1000p
C1035
1500p
R1044
2.2k
C1036
3300p
5+
6-
7
U1011-B
NJM5532M
R1045
620
R1047
2.2k
C1038
1000p
C1039
1500p
R1049
2.2k
C1040
3.3u 50V
C1041
3.3u 50V
R1050
10k
R1051
2.2k
C1042
3300p
3+
2-
1
U1012-A
NJM5532M
R1052
620
R1054
10k
R1055
2.2k R1056
2.2k C1044
1000p
C1045
1500p
R1058
2.2k
C1046
3300p
5+
6-
7
U1012-B
NJM5532M
R1059
620
R1061
2.2k
C1048
1000p
C1049
1500p
R1063
2.2k
C1050
3.3u 50V
C1051
3.3u 50V
R1064
10k
R1065
2.2k
C1052
3300p
3+
2-
1
U1013-A
NJM5532M R1066
620
R1068
10k
R1069
2.2k R1070
2.2k C1054
1000p
C1055
1500p
R1072
2.2k
C1056
3300p
5+
6-
7
U1013-B
NJM5532M
R1073
620
R1075
2.2k
C1058
1000p
C1059
1500p
R1077
2.2k
1DIR 2A0 3A1 4A2 5A3 6A4 7A5 8A6 9A7
10 GND 11
B7
12
B6
13
B5
14
B4
15
B3
16
B2
17
B1
18
B0
19
OE
20
VCC
U1014
74LVC245A
E
C
B
Q1001
2SC1815Y
E
C
BQ1002
2SC1815Y
R1078
2.2k
R1079
4.7k
R1080
2.2k
R1081
3.3k
R1082
1.8k
ADJ
OUT
IN
U1015
LM317
C1060
470u
16V
R1083
4.7k
E
C
B
Q1003
2SC1815Y R1084
2.2k
C1072
10u
16V
R1090
2.7k
R1091
2.7k
ADJ
OUT
IN
U1020
LM317
C1073
470u
16V
C1074
0.1u
C1075
0.1u
C1076
0.1u
C1078
0.1u
C1079
10u
16V
C1082
0.1u
C1081
0.1u
C1083
1u
50V
R1182
100
R1183
100
R1184
100
C1090
0.1u
C1091
3.3u
50V
C1093
0.1u
C1094
3.3u
50V
C1095
0.1u
C1096
1u
50V
L1002
10uH
L1003
10uH
L1005
10uH
C1099
0.1u
C1100
1u
50V
C1101
100p
C1102
100p
C1103
100p
C1104
100p
C1105
100p
C1106
100p
C1107
100p
C1108
100p
8
4U1010-C
NJM5532M
8
4U1011-C
NJM5532M
8
4U1012-C
NJM5532M
8
4U1013-C
NJM5532M
8
4U1023-C
NJM5532M
C1109
47u
16V
C1110
47u
16V
C1111
47u
16V
C1112
47u
16V
C1114
4700p
R1021
10k
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
J604B
To Mult i-Ch J604A
C1117
100u
16V
R1114
10k
C1118
N.I.
16V
C1119
N.I.
16V
R1115
100
C1121
220p
C1124
0.1u
C1125
0.1u
C1126
0.1u
C1127
0.1u C1128
0.1u
C1129
N.I.
C1130
4700p
C1131
4700p
V+
NC
OUT
GND
X1001
12.288MHz
Crystal Oscillator
L1007
10uH
C1132
1000p
C1133
N.I.
16V
1RST
2VL
3SDAT A
4SCLK
5LRCK
6MCLK
7M3
8M2
9M1
10 M0 11
FILT+
12
CMOUNT
13
BMUTEC
14
AOUTB-
15
AOUTB+
16
AGND
17
VA
18
AOUTA+
19
AOUTA-
20
AMUTEC
U1025
CS4392
C1137
10u 16V
C1138
10u 16V
R1116
5.62k
R1117
5.62k
R1118
1.18k
R1119
1.18k
C1139
2700p
R1120
1.5k
3+
2-1
U1028-A
NJM5532M
C1142 560p
R1121 1.5k
C1141
560p
C1140
2700p
C1143
10u 16V
C1144
10u 16V
R1122
5.62k
R1123
5.62k
R1124
1.18k
R1125
1.18k
C1145
2700p
R1126
1.5k
5+
6-7
U1028-B
NJM5532M
C1148 560p
R1127 1.5k
C1147
560p
C1146
2700p
C1155
1u
50V
1VLS
2SDIN1
3SDIN2
4SDIN3
5SCLK
6LRCK
7MCLK
8VD
9GND1
10 RST
11 DIF1/SCL/CCLK
12 DIF0/ SDA/CDIN
13 M1/AD0/CS
14 VLC 15
M2
16
FILT+
17
VQ
18
MUTE C3
19
AOUTB3
20
AOUTA3
21
GND2
22
VA
23
AOUTB2
24
AOUTA2
25
MUTE C2
26
AOUTB1
27
AOUTA1
28
MUTE C1
U1026
CS4360
C1134
2200p
C1135
2200p
C1136
2200p
8
4U1028-C
NJM5532M
C1013
0.1u C1014
1u
50V
C1015
0.1u
C1016
1u 50V
R113110k
R113210k
R113310k
R113410k
R113510k
R113610k
R113710k
R113810k
R1010
0
C1008
0.1u
C1009
0.1u
R1113
100
R1112
100
C1166
N.I.
R1166
1k
1
2
3
4
J1010B
to Digital
C1005
2.2u
16V
R1181
100
R1092
100
R1093
100
R1094
100
D1001
N.I.
R1191 33
R1192 33
R1193 33
R1194 33
1
2
J1009B
To DIGITAL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
J203B
to Keyboard
R1195 2k
R1197 2k
R1196
2k
R1198
2k
C1011
0.1u_(M)
63V
R1099
0
L1009
0
C1181
N.I.
J1001
0
R1221 2.7k
R1222
4.7k
C1160
0.01u
50V
R1231 4.7k
C1201 330p
R1232
4.7k
R1234
4.7k
C1202 330p
R1233 4.7k
R1239 4.7k
C1205 330p
R1240
4.7k
R1242
4.7k
C1206 330p
R1241 4.7k
R1243 4.7k
C1207 330p
R1244
4.7k
R1246
4.7k
C1208 330p
R1245 4.7k
R1236
4.7k
C1203 330p
R1235 4.7k
R1237 4.7k
C1204 330p
R1238
4.7k
L1001
10uH L1004
10uH
L1010
10uH
C1152
1u_(M)
63V
C1151
0.1u
C1157
0.1u
C1156
1u_(M)
63V
R1130
10k
C1092
1u_(M)
63V
C1150
0.1u
C1178
0.1u
C1154
1u_(M)
63V
C1177
0.1u
C1153
1u_(M)
63V
C1186
N.I.
C1185
N.I.
C1184
N.I.
C1183
100p
R1216
75
R1215
0
R1214
75
R1213
75
1M0
2MCLK
3VL
4SDOU T
5GND
6VD
7SCLK
8LRCK 9
RST
10
AINL
11
VQ
12
AINR
13
VA
14
REF_GND
15
FILT+
16
M1
U1027
CS5341
R1224
100k
R1223
100k
R1218 634
C1188 470p C0G
R1220
N.I.
R1219
N.I.
C1187 470p C0G
R1217 634
R1176
100k
R1175
100k
R1172
47k
R1171
47k
C1176
0.01u
C0G
R1174
47k
C1172
4.7u16V
R1178
91
5+
6-7
U1023-B
NJM5532M
C1175
0.01u
C0G
1
2
3
J715B
To Mainboard R1173
47k
C1171
4.7u16V
R1177
91
3+
2-1
U1023-A
NJM5532M
L1011
5.6uH
C1209
68p
C1210
0.1u_(M)
63V
L1012
10uH
L1015
10uH
L1014
10uH
R1248
N.I.
R1247
0
R1249
0
R1250
N.I.
L1013
10uH
R1251
0
R1254
N.I.
R1252N.I.
R1253 N.I.
AGND
+2.5VD
DGND AGND
+2.5VD
DGND
DGND
+3.5VD
DGND
DGND
AGND
DGND
AGND AGND
DGND
+8V
DGND
DGND
DGND
DGND
+5VD
+5VD
+3.5VD
DGND
DGND
DGND
+3.5VD
DGND
DGND
DGND
+8V
DGND
+2.5VD
DGND
+2.5VD
+5VD
AGNDAGND
AGND
+5VD
AGND
+3.5VD
DGND AGND
AGND
AGND
+12V
+12V-12V
-12V
DGND
AGND
+3.5VD
+5VD
DGND
+5VD
+12V -12V
+3.5VD
+2.5VD
AGND
DGND
+5VD
DGND
DGND
CEN
AGND
AGND
AGND
AGND
AGND
AGND
AGND
AGND
+12V
-12V
SUB
SL
SR
BSL
BSR
FL
FR
+12V
-12V
DGND
DGND
DGND
DGND
DGND
DGND
DGND DGND
DGND
DGND
DGND
+3.5VD
DGND
+8V
DGND
+3.5VD
+3.5VD
AGND
AGND
DGND
DGND
DGND
DGND
DGND
DGND DGND DGND DGND
+2.5VD
DGND
DGND
DGND
AGND
DGND
+5VD
+5VD
251_C
251_B
251_A
DGND
DGND
DGND DGND
CDIN
CLK
8415_CDOUT
8415_CS
49326_CS
49326_RESET
INTREQ
ABOOT
D/A
49326_CDOUT
251_A
251_B
251_C
A17
A16
A15
DGND
4360/4392/5333/8415_RST
+8V
+8V
+5VD
+5VD
DGND
+5VD
DGND
+2.5VA
AGND
AGND
AGND
AGND
+5VD
+3.5VD
+3.5VD
DGND
DGND
AGND
AGND
+3.5VD
DGND
AGND
AGND
AGNDAGND
AGNDAGND
AGND
DGND
+3.5VD +5VD
+5VD+3.5VD
16
SCHEMATIC DIAGRAM
DSP BOARD (FINAL SERVICE PARTS VERSION)
NOTE:
1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%.
2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 5%.

x1 Q701 module with flying leads
x1 black foam block, with double sided tape on two sides
x1 set of instructions
When Q701 becomes defective, the T752 will turn on, but he VFD will not light up.
The purpose of replacing the transistor Q701 with a module is to facilitate a more reliable and
quicker repair process with a minimum of parts disturbance, if and when Q701 becomes
defective.
xJ1 is DC output
xJ2 is AC input
xJ3 is ground
xConnect the long ground wire to the DSP ground, top right hand side of the DSP
module
xConnect the DC Output to jumper JMP138 be sure not to heat up the solder
connections on the bottom of the main PCB: Use heat-sink tongs.
xTap into the AC Input to the AC source wire #10 of cable AC17.6V2
Service Hint for replacing Q701 in T752/T762 with 95-0907627-12-01
95-0907627-12-01
17

xCut out the following parts:
1. Diodes D709 and D710
2. Q701 (cut out or pull out)
3. Cut out R702
18
Another view of tapping into the AC Input source wire #10 of cable AC17.6V2