HP 8112A Operating, Programming And Servicing Manual page 223

Note
Slope Generator
Width vernier current can be checked by measuring the voltage
across R245.
7. Set HP 8 1 1 2A PE R to 20 ms
8. Check signal levels against Table 10.3- 1 5
Table 1 0.3-15. Width Generator Signal Levels
WID Setting Voltage across R245
1 . Set the HP 8 1 1 2A to R CL 0 and press the � key:
2. Check the input signal from the width generator at pin 1 of U301
against Figure 10.3- 16
3. Check the ramp current input at pins 9 and 12 of U301 against
Figure 1 0.3- 16
4 . Check the signals being sent to the shaper IC (waveforms at TP l ,
TP4 and pin 2 1 of U301 ) against Figure 1 0.3- 16.
P i n s 9 &
P 1 n
TP
TP
Figure 1 0.3-1 6. Slope Generator Input and Output signals
1 +0.125 v
ms
5
ms +0.004 v
9.99 -0.02 v
ms
+ l
. B V
1 2
OV
1
I
I
4
I
+0.
I
r 1 00us
1 4 V
+0 .
I
2 5 V
I
I
5 I
+0 . I
1 4 V
- 0
3 9 V
0
-
.
Servicing the Timing and 1 0.3-2 1
Slope Generators
----�1
ms
l