[Test-Equipment] HP-141-T info needed

[Alan Melia]

Hi Chuck may be right about the mixer diodes but it doesnt sound like it.
There are a number of other places to look first before diving into a
difficult (or expensive repair)

If you are seeing the 30MHz cal signal and harmonics it sounds as though the
mixer is working in some fashion. The next thing to look at is the mating
D-connectors between the IF and RF modules I actually had one pin bent
inwards on one of the systems I acquired and got exactly the same symptom
that you describe......not gain...you may find the cal signal is does not
align with the quoted value (engraved on the panel) Make sure that these
connectors mate properly before trying to offer up the two modules to the
frame. They can be misaligned and not seated properly ...without the problen
of a bent pin (I managed to carefully straighten it with it breaking !!)

The next most important thing to do is take the bottom cover off the the
frame use the 141T manual and locate the power supply test pins and adjuster
pots. These will have drifted out. Reset them with a reasonable good (one
you trust) DMM they do need to be set farly accurately and the carbon
resistors have a record of drifing up. If you run out of adjustment you may
need to replace one or more fixed  resistor. Do the adjustment in the right
order as per the book. The service of these units is not too difficult I
have managed for some time without extender cards (though I collected the
sockets to make them. (I think the 4mm spacing pins or 0.156in. It is very
easy to suspect the diodes and it is often the first advice you will get.
they are easily blown up if you use with transmitters. A power attenuator is
a good investment!

They are B I G  units but are fun to use and maintain, and still do a good
job at a bargain price.

Join the HP-Agilent Yahoo Group fo the best advice around....many ex HP
employees are members !!


Best Wishes
Alan G3NYK