HP 8340A Service Manual page 221

A45
PRE LEVELER
YES
I 4l IS
PRELEVELER 151 IS YO RF
RF POWER AT POWER OUT OK?
A45-J3 OK ?
YES
MAIN PATH
R F PROBLEM!
NO NO
2) IS FRONT 31 IS YO FREQ
YO UNLK I) ARE OTHER YES
START PANEL RF OFFSET
cw MOD!:: LOOPS OK ?
POWER OK ? < ±25MHz ?
NO
TROUBLESHOOT
OTHER LOOPS
Scans by HB9HCA and HB9FSX
A55 A54 YO A54 YO PRETUNE
A44 1158 SWEEP
YO DRIVER/ PRE TUNE DELAY COMP
YO GENERATOR
A47 SENSE RES DELAY COMP BLOCK E
YES YES YES YES ANO
16) IS THE YO A59 DIGITAL
NO 17) IS PRETUNE 18) IS VSWP 19) IS L VSX NO
MAIN COIL INTERFACE
VOLTAGE OK ? VOLTAGE OK? LOW ?
DRIVE OK ? BOARD
REMOVE YO TUNE
AND FM COIL
4) IS YO TUNE 7) IS MIN OUT Bl IS 20/30 OUT
YES 61 rs HLEY
DRIVE CABLES.
RAILED POS OR FREQUENCY AND FREQUENCY AND
HIGH? PLACE 50.n
POWER OK ?
NEG? (--.6.9Vl POWEft OK ?
LOAD ON YO
TUNE CABLE
NO NO NO NO
A59 DIGITAL
51 IS HULY N O
INTERFACE MIN LOOP 20130 LOOP
HIGH ?
BOARD
YES
A49 YO LOOP
PHASE DETECTOR
BLOCK J
NO
9) IS YO
10) IS OPEN
FREQUENCY l I ) IS SAMPLER
LOOP YO FREQ A49 'l'O LOOP
CHANGE IF FREQUENCY
±5MHz ®- 2.30, PHASE DETECTOR
PROPORTIONAL AND POWE� OK?
6.99GHz?
TO YO TUNE ?
NO NO
13) IS
A55 121 IS RF
PRELEVELER NO A45
YO DRIVER POWER INTO
POWER out
PRELEVELER
SAMPLER OK ?
BLOCK E
OFJ2 0K?
.
YES YES
A46 7 GHz;
A48 YO LOOP LOW PASS
SAMPLER FILTER
AND CABLES
Figure 8D-2b. Sweep Generator and YO Loop Troubleshooting Flowchart