UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Marconi Radio communication Test set 2955A

Biggles · 13th Sep 2018, 11:20 pm

I know it's a fairly common problem with the 2955, and unfortunately both mine have intermittent attenuators. We used to send them back for repair to Marconi with this fault as it required re-calibrating after so I have never taken the attenuator block apart. Exercising the relays by winding the signal level up and down a few times seems to help sometimes. One day I may be brave enough and find the time to dismantle mine. I'll bet the relays are expensive too. I suppose you could use a fixed external attenuator on the output to slug the real level output to a range that is working but this would be very much a last resort, and also creates the risk of blowing up your attenuator if you happened to transmit into it by mistake.
Alan.

13th Sep 2018, 11:20 pm	#2
Biggles Rest in Peace Join Date: Feb 2004 Location: Hexham, Northumberland, UK. Posts: 2,234	Re: Marconi Radio communication Test set 2955A I know it's a fairly common problem with the 2955, and unfortunately both mine have intermittent attenuators. We used to send them back for repair to Marconi with this fault as it required re-calibrating after so I have never taken the attenuator block apart. Exercising the relays by winding the signal level up and down a few times seems to help sometimes. One day I may be brave enough and find the time to dismantle mine. I'll bet the relays are expensive too. I suppose you could use a fixed external attenuator on the output to slug the real level output to a range that is working but this would be very much a last resort, and also creates the risk of blowing up your attenuator if you happened to transmit into it by mistake. Alan.