5. Compare the signals at the following test points with those illustrated in Figure
X POS: | A2J202 pin 14 | |
Y POS: | A2J202 | pin 3 |
Z OUT: | A2J201 | pin 3 |
| BLANKING: A2J202 pin 15 |
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Note | Waveforms displayed on an analog scope may show considerably more spikes. |
| This is normal and is due to the wider displayed bandwidth. |
|
|
6. Troubleshoot the circuits associated with any bad waveforms.
3 . 0 0 V/di v 0 . 0 0 v 1 . 0 0 ms/dlv 0 . 0 0 0 s
xPOS
Y POS
z POS
t
B L A N K 
I biG
t
SK191
Figure
Blanking
See function block J of A2 Controller Schematic Diagram (sheet 1 of 4) in the
1.Using an oscilloscope, check for blanking pulses at A2J202 pin 15. A2U206 pin 6 should be at a TTL high. Blanking pulses turn the CRT beam off during the sample time of the line generators and when moving the CRT beam to a new position for drawing the next vector.
2.Set an oscilloscope to the following settings:
Amplitude Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 V/div
Amplitude Offset . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . +2.5 V
Sweep Time . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . 20 ps/div
Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..External
3. Externally trigger the oscilloscope off the signal at A2U207 pin 8 (LBRIGHT).
Controller Section