HP 8340A Service Manual page 214

With the YO TUNE and FM COIL cables disconnected
load on the YO TUNE cable,
should be within a +5 MHz window over the entire YO operating
range. The YO accuracy should be checked at 2.300 and 6.999 GHz.
If the actual YO frequency is outside of these limits, then go to
question 17� if not, then proceed to question 11.
(11) IS SAMPLER IF
Check for the correct frequency and power for the SAMPLER IF. The
frequency accuracy
YO. If the SAMPLER IF frequency and power-are correct,
troubleshoot the A49 YO Loop Phase Detector�
proceed to question 12.
(12) IS RF POWER INTO THE A48 YO LOOP SAMPLER OK?
Check the RF signal power into the A48 YO Loop Sampler. If the RF
power is correct,
no signal is present or if the power is incorrect,
to question 13.
IS PRE-LEVELER POWER OUT OF A45J2 OK?
(13)
Check the coupled-back RF power out of the A45 Preleveler at
A45J2. If no signal is present or the power level is incorrect,
then troubleshoot the A45 Preleveler. If the RF power is correct,
then troubleshoot the A46 7 GHz Low Pass Filter and connecting
cables.
(14) IS PRE-LEVELER POWER OUT OF A45J3 OK?
This portion of the troubleshooting guide is a branch from
question 2.
Check the RF power out of the A45 Preleveler at A45J3. If the
signal is present at the correct power,
exists in the Main RF path. To continue to troubleshoot the YO
UNLK, however,
the power output is low,
(15) IS YO POWER OUT OK?
Check the RF power out of the YO. If the power is correct,
troupleshoot the A45 Preleveler. If no signal is present or if
the power is low,
(16) IS THE YO MAIN COIL DRIVE OK?
Check the YO MAIN COIL DRIVE. This can be done by testing the
8-292
Model 8340A - Service
A49J2),
FREQUENCY AND POWER OK?
(open loop ) should be +5 MHz, the same as the
then troubleshoot the A48 YO Loop Sampler. If
go to question 3. If no signal is present or if
then proceed to question 15.
proceed to question 16.
Scans by HB9HCA and HB9FSX
(and a 50 Ohm
the YO frequency accuracy
if not correct, then
then a problem also
then
then proceed
then