Bush AC34 fault - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Paul Stenning · 6th Mar 2005, 11:59 am

An intermittent heather-cathode short-circuit in the UCH42 would cause the UBC41 heater to lose power, but I would still expect the problem to fade in and out over a few seconds (as the heater cools and heats) rather than abrupt.

The only other explanation could be an intermittent fault in the UCH42 that causes excessive HT to be drawn - more likely on the mixer side. This would be apparent on voltage tests, but I don't think brymac ever managed to get these while the set was misbehaving.

So it's still a mystery - but it is sorted!

6th Mar 2005, 11:59 am	#21
Paul Stenning Administrator Join Date: Dec 2002 Location: Cardiff Posts: 9,071	Re: Bush AC34 fault An intermittent heather-cathode short-circuit in the UCH42 would cause the UBC41 heater to lose power, but I would still expect the problem to fade in and out over a few seconds (as the heater cools and heats) rather than abrupt. The only other explanation could be an intermittent fault in the UCH42 that causes excessive HT to be drawn - more likely on the mixer side. This would be apparent on voltage tests, but I don't think brymac ever managed to get these while the set was misbehaving. So it's still a mystery - but it is sorted! __________________ Paul Stenning Forum Admin/Owner and BVWS Webmaster