Kurzweil PC88 - Page 98

Chapter 4
Test
Point
Test Points
Name
Location
Schematic
Location
Troubleshooting
Activity
All Test Points will be found on the Engine Board schematics, sheets 1 through 6.
TP1
TP4
TP6
TP10
TP11
TP14
TP15
TP20
TP21
TP28
TP29
TP30
TP31
TP32
TP33
TP34
TP35
TP36
TP37
TP38
TP39
TP40
TP41
TP42
TP43
TP44
TP45
TP46
TP47
TP48
TP49
TP50
TP51
TP52
TP53
OSC20*
P8,
U8
C7,
Sht.
4
of
6
Clock,
19.968
MHz,
approx.
.05ys
OSC16
P2,
US
G1,
Sht.
2
of
6
Clock,
16.000MHz,
.0625,1s
_CLK16
P12,
US
H1,
Sht.
2
of
6
Clock,
16.000MHz,
.0625ys
NVRAMCSb
P3,Q1
G5,
Sht
3
of
6 5
Volts
PWRUPRSTINb
P1,Q1
G5,
Sht.
3
of
6
5
Volts
INTMIDITxD
P27,
U21
L5,
Sht.
2
of
6
5
Volts
INTMIDIRxD
P31,
U21
L5,
Sht.
2
of
6
5
Volts
RESETb
P4,
U20
J8,
Sht.
2
of
6
5
Volts
RESET
P10,U20
E7,
Sht.
2
of
6
0
Volts
_IEXTMIDIRxD
P32,
U21
16,
Sht.
2
of
6
5
Volts
_EXTMIDITHRU
_
P8,
U5
K7,
Sht.
2
of
6
5
Volts
_EXTMIDITxD
P6,
US
K6,
Sht.
2
of
6
5
Volts
IBRO
P39,
U17
H1,
Sht.
1
of
6
High,
low
pulse
6.51s
wide
every
.25ms
IBR1
P37,
U17
H1,
Sht.
1
of
6
High,
low
pulse
6.51s
wide
every
.25ms
IBR2
P35,
U17
H1,
Sht.
1
of
6
High,
low
pulse
151s
every
.25ms
IBR3
P33,
U17
H1,
Sht.
1
of
6
High,
low
pulse
6.5,1s
every
.25ms
IBR4
P8,
U17
H1,
Sht.
1
of
6
High,
low
pulse
6.5us
every
.25ms
IBR5
P6,
U17
H1,
Sht.
1
of
6
High,
low
pulse
4
ts
every
.25ms
IBTO
P19,
U17
H1,
Sht.
1
of
6
High,
low
pulse
.12ms
wide
every
1.2ms
IBT1
P18,
U17
H1,
Sht.
1
of
6
High,
low
pulse
.12ms
wide
every
1.2ms
IBT2
P17,
U17
H1,
Sht.
1
of
6
High,
low
pulse
.12ms
wide
every
1.2ms
IBT3
P16,
U17
H1,
Sht.
1
of
6
High,
low
pulse
.12ms
wide
every
1.2ms
IBT4
P15,
U17
H1,
Sht.
1
of
6
High,
low
pulse
.12ms
wide
every
1.2ms
IBT5
P14,
U17
H1,
Sht.
1
of
6
High,
low
pulse
.12ms
wide
every
1.2ms
IBT6
P13,
U17
H1,
Sht.
1
of
6
High,
low
pulse
.12ms
wide
every
1.2ms
IBT7
P12,
U17
H1,
Sht.
1
of
6
High,
low
pulse
.12ms
wide
every
1.2ms
IMKO
P40,
U17
G1,
Sht.
1
of
6
High,
low
pulse
6.5us
wide
every
.25ms
IMK1
P38,
U17
G1,
Sht.
1
of
6
High,
low
pulse
6.5ys
wide
every
.25ms
IMK2
P36,
U17
GI,
Sht.
1
of
6
High,
low
pulse
6.5,1s
wide
every
.25ms
IMK3
P34,
U17
G1,
Sht.
1
of
6
High,
low
pulse
6.5us
wide
every
.25
ms
IMK4
P9,
U17
G1,
Sht.
1
of
6
High,
low
pulse
6.5us
wide
every
.25ms
IMKS5
P7,
U17
G1,
Sht.
1
of
6
High,
low
pulse
41s
wide
every
.25ms
ITTO
P57,
U17
G1,
Sht.
1
of
6
5
Volts
ITT1
P56,
U17
G1,
Sht.
1
of
6
5
Volts
ITT2
P55,
U17
GI,
Sht.
1
of
6
5
Volts
PC88 Service Manual
4-18