Cossor 4100A - UK Vintage Radio Repair and Restoration Discussion Forum

raresvintea · 12th Sep 2013, 3:21 pm

Hello. I am a happy owner on a Cossor 4100A, and thanks to the man who gave it to me!

It has a little problem. When it's on B channel it shows only half of signal on OX. On channel A the signal is complete.

Do you know any possible component that can give this defect?

WME_bill · 13th Sep 2013, 9:15 pm

I am afraid you will just have to get down to a careful search. It is clearly in the Y pre-amplifier for B channel. You do not say whether the signal is half is intended to mean half the amplitude (ie reduced gain) or only half the wave form (ie chopped off, as if half the balanced stages are cutting off). You will need the circuit and the manual, but it doesn't sound too desperate. I attach the circuits of the Y amplifier to help you on your way. Let us know how you get on. wme_bill m0wpn

raresvintea · 13th Sep 2013, 9:19 pm

"Only half the wave form".

I nee dto reconize that i need more skills to repair one of that oscilloscopes, and withouts certains test point it will remain like this.

12th Sep 2013, 3:21 pm	#1
raresvintea Retired Dormant Member Join Date: Sep 2013 Location: Romania, Bucharest Posts: 2	Cossor 4100A Hello. I am a happy owner on a Cossor 4100A, and thanks to the man who gave it to me! It has a little problem. When it's on B channel it shows only half of signal on OX. On channel A the signal is complete. Do you know any possible component that can give this defect?

13th Sep 2013, 9:19 pm	#3
raresvintea Retired Dormant Member Join Date: Sep 2013 Location: Romania, Bucharest Posts: 2	Re: Cossor 4100A "Only half the wave form". I nee dto reconize that i need more skills to repair one of that oscilloscopes, and withouts certains test point it will remain like this.