I'd immediately suspect a shorted tantalum capacitor on one of the supply
lines. I had one with nearly-identical symptoms a few years ago, and that
was the cause.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
On October 9, 2015 9:36:34 PM "bunge@... [hp_agilent_equipment]"
<hp_agilent_equipment@...> wrote:
My 8350B with 83592B plug-in turns on with flickering displays that go
blank and hangs the 8350B with no error message, and no response to any
switches on either the plug-in or mainframe. While flickering for a few
seconds the 8350B displays show -310 MHz start and 20 GHz stop.
It does the same to a second known working 8350B. All data and address
lines are active when hung so I don't understand why the 8350B does not
respond.
If I press CW while the displays are flickering it responds. I may have to
power down and up again to then enter a CW frequency, it comes up showing
CW. Once in this state I can run tests and all front panel entries work. I
ran all the A3 tests which show the ROMs and address decoders are OK.
The frequency in CW is high by 13 to 47 MHz going from 50 MHz to 18 GHz (it
covers 0.01 to 20 GHz).
The power is way off. The display shows -2 to +23 dBm. Is this normal? (no
opt 002 attenuator).
-2 is actually -17 dbM and power does not increase until about +2.5 dBm. At
+10 dbM it is actually +9.5 dBm.
Tomorrow I will start a full calibration. Suggestions and tips would be
appreciated.
Is there a battery backed memory in the 8350B? It seems to remember the
setup for quite a while after being turned off. Is the save-n non-volatile?
Does anyone have a spare cover for the PCBs for sale? The plate that goes
on top of the 83592B and has many screws. it also holds the big heat sink
in place. It is obvious that someone else's fingers have been inside this
plug-in.
Dave McGuire