Marconi 2955B minor problem

Hi guy´s

Ive been using the old Marconi 2955B testset for several years now and it´s still works like a charm - wonderful piece of machinery..

Lately a problem has occured that i immediatly cant figure out... when you measure output in TX test, the unit doesent immediatly switch over
but hesitates before it engages the relay, you have to tx in to it several times before it reacts...
Also i get a "feedback" noise ="squeeling" when i put power in to it the first few seconds (not the power limit signal ) - then you can hear the relay click and it displays the power/values

Since i dont have any schematics for this thing - anyone that has experienced this problem and can direct me before i take it apart?

""All test ok, everything else works just fine""

Greatful for any ideas

best regards
/ Anders

I am sure you can download it on the web. Here is one source that appears to have it. Worth a try.
https://www.eserviceinfo.com/index.php?what=search2&searchstring=marconi+2955b

It may be a problem with the RF detection circuit and/or switch-over relays.

Attached is the diagrams from a 2955A/R in my collection, which may be very similar to the B model.

E-design said:

I am sure you can download it on the web. Here is one source that appears to have it. Worth a try.
https://www.eserviceinfo.com/index.php?what=search2&searchstring=marconi+2955b

It may be a problem with the RF detection circuit and/or switch-over relays.

Attached is the diagrams from a 2955A/R in my collection, which may be very similar to the B model.

Click to expand...

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Thanks, but this link doesent seem to work - the only thing that i can download from this site is a converter between formats...

/ A

You must pick from the list on the page. This should get you there: https://www.eserviceinfo.com/downloadsm/8101/Marconi_2955.html

There are three .rar parts to download (0,1,2)