Installation guide

Troubleshooting

Troubleshooting Assembly Level Problems

1-40

500 Power Supply

• If the ± 15 V and +5.2 V supplies are good on the connector pins indicated:

a. Turn power off, remove the A17 Synthesizer (Option 501, 502, 503, 504) and ohm the connection

between the appropriate J42 and J10 pins.

— If the connection is good, replace the A17 Synthesizer (Option 501, 502, 503, 504).

(Refer to “A17 Synthesizer (Option 501, 502, 503, 504)” on page 2-40.)

— If the connection is bad, replace the A19 Daughterboard.

(Refer to “A19 Daughterboard” on page 2-44.)

• If the ± 15 V and +5.2 V supplies are bad on the connector pins indicated:

a. Check the origin of the supply.

— If the supply voltage is good at the origin, replace the A23 Motherboard.

(Refer to “A23 Motherboard” on page 2-52.)

— If the supply voltage is bad at the origin, troubleshoot the problem using that assembly's

troubleshooting procedure.

501 Loop Gain

• Replace the A17 Synthesizer (Option 501, 502, 503, 504).

502 Tuning Voltage

• If the +32 V and +9 V supplies are good on the connector pins indicated:.

a. Turn power off, remove the A17 Synthesizer (Option 501, 502, 503, 504), and ohm the connection

between the appropriate J42 and J10 pins.

— If the connection is good:

a. Re-insert the A17 Synthesizer (Option 501, 502, 503, 504).

b. Turn power on and check the 10 MHz signal on the A23 Motherboard at J10 pin 99 using an

oscilloscope.

The signal should have a period of 100 ns and an amplitude of greater than 1.2 Vp-p.

— If the signal is good, replace the A17 Synthesizer (Option 501, 502, 503, 504).

(Refer to “A17 Synthesizer (Option 501, 502, 503, 504)” on page 2-40.)

— If the signal is bad, troubleshoot the A18 Reference.

(Refer to “A18 Reference” on page 2-42.)