HP 8112A Operating, Programming And Servicing Manual page 255
50 mhz programmable pulse generator
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- Operating, programming and servicing manual (112 pages) ,
- Operating, programming and servicing manual (406 pages)
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Troubleshooting
Note
Address Decoders
a key, ( LCL ) for example, t o return the microprocessor to normal
•
If an error code is being displayed by the HP 81 12A you must press
operation before troubleshooting.
•
The component layout and locator for the standard control board
A2 is at the end of the chapter.
Verify the following voltages:
•
DAC supply U9 pin 2: +5 V
•
DAC reference TP9: - 1 V
•
DAC reference TP8: -9 V
1 . Set up the HP 81 12A as follows:
Timer
RCL
PER
2. Check that pin 3 of U26 is delivering a signal of approximately
100 Hz.
The address decoders can be checked using signature analysis:
a. Set the Pl wire on board A3 ( See Chapter 10.7 ) to position Pl.
1. Set the microprocessor to free run mode as follows:
b. Disconnect Jumper A2W l .
c . Connect RES on A 3 to ground for a short time t o ensure the
microprocessor is reset .
d. Connect the signature analyser ground to the Control Board
ground and connect the probes as follows:
Sig. Analyser
Start
Stop
Clock
e. Verify that the reading at the Microprocessor +5 V is 0003. If
it is not, then the microprocessor is not free running.
f. Check the signatures of U l , U15 and U16 against those given
in Table 1 0.5- 1
0
10 µs
A3 µP Board
Connections
.f
TP "SA"
.r
TP "SP"
\
TP "E"
Servicing the Control Board 1 0.5-1 1
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