UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

NikPrice · 1st Feb 2020, 5:29 pm

I have an old yellow and brown button FM4 in the 11xxx serial number range which I am trying to repair after a battery meltdown.

The problem I am stuck on is on power up the tune volts shoot up to the roof!

In about a second the voltage rises to 8.38V on REF L and 11.35V on REF H.

I've changed the CPU, all electrolytic caps, D24, T11 and from there I'm stumped.

Does anyone have any ideas or theories?

Thanks,
Nik.

1st Feb 2020, 5:29 pm	#1
NikPrice Triode Join Date: Feb 2020 Location: Portsmouth, Hampshire, UK. Posts: 35	Another Quad FM4 problem I have an old yellow and brown button FM4 in the 11xxx serial number range which I am trying to repair after a battery meltdown. The problem I am stuck on is on power up the tune volts shoot up to the roof! In about a second the voltage rises to 8.38V on REF L and 11.35V on REF H. I've changed the CPU, all electrolytic caps, D24, T11 and from there I'm stumped. Does anyone have any ideas or theories? Thanks, Nik.