HP 8112A, Operating, Programming And Servicing Manual

Page: 220 / 406

Note
Period Vernier Current can be checked by measuring the voltage
across
R212.
Table 1 0.3- 1 1 . Period Generator Signal Levels
PER Setting Voltage across R21 2
1
ms
+0.16 v
5
ms
+0.003 v
9.99
ms
-0.016 v
Delay Generator
1. Set up the HP 81 12A as follows:
RCL
DEL
DBL 0
650 µs or
200 µs
2. Check the input signal from the period generator pin 7 of U220
against Figure 10.3- 1 1.
50% 50%
! ms
II
DEL 6 5 0u s
DEL 200us
Figure 1 0.3- 1 1 . Delay Generator l/P O/P waveforms
3. Check the ramp signal at pin 20 of U220 against Figure 10.3-12.
4. Check the signal being sent to the width generator IC240
at TP2
against Figure 10.3-11.
-1 490nsr-
-
0
.
?V
i
i !\_
I
I :::::::
I I
:::::::
I
I
- !
.9V
-_.j
DEL
650us /.-
Figure 1 0.3-1 2. Delay Generator ramp signal pin 20
5. Check the Delay Generator operation against Table 10.3-12
1 0.3- 1 8 Servicing the Timing and
Slope Generators