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-----Original Message-----
From: hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...]On Behalf Of
microwaveengineer1968
Sent: Thursday, November 15, 2007 9:31 PM
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] Re: HP-8443A Tracking Generator Problems


This is the link for a manual for the 8443A

Now down to the bone my friend, i have looked at the manual and
compiled some preliminary checks for you to do, this assumes that you
have acess to a counter to 500MHz and maybe a powermeter or scope
with appropriate bandwidth.
First off you need to verify the operation of the tracking generator
portion of your unit, dont worry about the counter for now, basically
the 8443 receives three signals from the 8553 and 8552 units, those
signals are mixed together sequentially to form a 0-110MHz signal
which is then amplified and leveled, the manual has a nice block
diagram in it btw !
The first signal is a 200-310MHz which is basically the 1st LO of the
8553, the amplitude is supposed to be -6dBm, the next signal is a
150MHz fixed LO @ -2dBm and the third Signal is a 47MHz fixed lo @ -
7dBm
First connect your counter to the RF output of your 8443A, set the
attenuator to 0dB and then set the analyzer to zero span and tune the
frequency and see if the counter indicates a frequency reading in
accordance to your analyzer scale, if you dont get any indication you
will have to verify the presence of your LO signals, you may just
have a bad interconnect cable to your analyzer, measure the 150MHz
signal on A11 J1 (you have to remove the cable and then measure the
signal coming out of the cable) , measure the 47MHz signal on A13 J1
(once again measure whats coming out of the cable) and the 3MHz fixed
LO on J3 (cable) then move on to A9 J1 on this cable you should be
able to measure a signal from 200-310MHz the frequency should be
tuning when you turn the tuning knob on your RF Section.
Do those tests and let me know the outcome.

--- In hp_agilent_equipment@..., "David C. Hallam"
<dhallam@...> wrote:

I have some problems with my 8443A and need help locating the

issues. The

nixie tube display shows all 0. I believe the tracking generator

is still

working because the marker is on the screen of the 141T. I can

connect the

RF output of the 8443A to my HP-5245L counter which will display

the marker

frequency. I can move the maker with 8533B frequency control and

the

display on the 5245L will change with the movement of the marker.

The 8443A will function as a counter because I can set it in the

external

mode and use it as a frequency counter.

I followed the counter trouble shooting tree in the manual and

reach the end

point where it says to repair A5. However in the service section

for A5, I

get oscilloscope displays from each of the 6 test points on A5 that

match

the photo in the manual which leaves me wondering. I don't have the
extender to remove the module from the 8443A and measure the

voltages, etc.

at the points indicated on the repair table.

Does anyone have any suggestions about what to do next? Is my

conclusion

that the tracking generator portion functioning properly logical?

My skill

level as an electronics technician is not that great with

instruments like

this.

David
KC2JD/4

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