
TM 9-4935-601-14-7&P
Model 8640B
INSTRUMENT MODIFICATIONS
7-95.
The problem may be corrected as follows:
a. Remove Q8.
b. Solder a jumper between the base and emitter
holes where Q8 was loaded.
c. If the circuit has R54 (825 ohm collector resistor
for Q8), carefully unsolder it.
d. Remove R44 (42.2K).
e. Solder the 825 ohm resistor in place of R44.
The HP Part Number is 0757-0421.
f. Check operation by increasing the CW RF
output level above +19 dBm. The REDUCE PEAK
POWER lamp should light at a level b19 and
+22 dBm.
7-90
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