Digital Circuit Checks; Table 4-4 Digital Circuit Checks - Keithley 2182 Service Manual

4-12 Troubleshooting

Digital circuit checks

Digital circuit problems can be checked out using
Table 4-4
Digital circuit checks
Step
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Item/component Required condition
Power-on test RAM OK, ROM OK.
TP301 Digital common.
U103 pin 32 +5V
U101 pin 48 Low on power-up, then goes
high.
U101, lines A1-A18 Check for stuck bits.
U101, lines D0-D15 Check for stuck bits.
U101 pin 44 14.7456MHz
U110 pin 13 Pulse train during RS-232 I/O.
U110 pin 14 Pulse train during RS-232 I/O.
U106 pins 34-42 Pulse train during IEEE-488 I/O. IEEE-488 data bus.
U106 pins 26-31 Pulses during IEEE-488 I/O.
U106 pin 24 Low with remote enabled.
U106 pin 25 Low during interface clear.
U101 pin 84 Pulse train.
U101 pin 91 Pulse train.
U101 pin 90 Pulse train.
U101 pin 89 Pulse train.
Table 4-4.
Remarks
Verify that RAM and
ROM are functional.
All signals referenced to
digital common.
Digital logic supply.
MPU RESET line.
MPU address bus.
MPU data bus.
MPU clock.
RS-232 RX line.
RS-232 TX line.
IEEE-488 command lines.
IEEE-488 REN line.
IEEE-488 IFC line.
ADRXB
ADTX
ADCLK
ADTS