HP 437B - ANALOG BOARD FUNCTIONAL VERIFICATION (continued)

HP 437B
Service Sheet BD1
replacing the components doesn’t solve the problem, replace the Analog
board.
12. Set the range calibrator’s RANGE switch to | mW.
13. Press the Power Meter’s CAL key. Enter a REF CF of 100.0%.
14.
Connect
the
DVM
to
the
RECORDER
OUTPUT
connector
on
the
rear
panel.
15. Verify that the DVM reading is 1.000V +0.003 Vdc.
16. If the voltage is correct, go to Step 18. If the voltage is incorrect,
continue with the next step.
17. Using the logic probe, verify the presence of TTL signals at A4U18 pins
12 and 13 (on Service Sheet A4c). If the signals are present, turn to
Service Sheet A4c to troubleshoot the Recorder Output circuit block.
18. Press the Power Meter’s PWR REF (SHIFTed (©) key.
19. Set the oscilloscope as follows:
Vertical Sensitivity ............. cece eee eee eee 100 mV/div
SWeED 5 oto ee aueatadiuie sGakai vines eae viele ees 5 ns/div
"TTR RCTING vse eines ee ealowet Seca uhi okie Se vane neat Internal
Coupling’ ....ces henge hieeeeeiees soe scan tiawateetes DC, 502
20. Connect the oscilloscope to the POWER REF output connector on the
Power Meter’s front panel.
21. Verify the 50 MHz signal as shown in Figure 8-2.
anaes
Cec Silica 2]
PIfINT TINT | Of
yi | a
GEALEEEA
100 mV/DIV
| | he
5 ns/DIV
Figure 8-2. 50 MHz POWER REF Waveform
22. If the 50 MHz signal can be verified, the Power Meter is fully
operational. No further troubleshooting is necessary. If the 50 MHz
signal cannot be verified, proceed to Step 23.
SERVICE 8-31