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Station X · 18th Jan 2012, 10:47 pm

OK.

We now have HT on the UL41 anode which is good.

There are three problems though.

Voltage on the UY41 Heater is 158.6-116.1=42.5V it should be 31V.
Voltage on the UL41 Heater is 116.2. 98.4=17.8V it should be 45V
Voltage on UL41 cathode is low. It should be about 8V.

Low voltage on UL41 cathode indicates no anode or screen current. This may be down to the low heater voltage reducing the valve's emission.

Try this. Switch off. Pull out all the valves. Measure the resistance to chassis of each heater pin. (The brown wires). All bar two pins should read infinite resistance or open circuit.

18th Jan 2012, 10:47 pm	#122
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Bush AC34, no sound. OK. We now have HT on the UL41 anode which is good. There are three problems though. Voltage on the UY41 Heater is 158.6-116.1=42.5V it should be 31V. Voltage on the UL41 Heater is 116.2. 98.4=17.8V it should be 45V Voltage on UL41 cathode is low. It should be about 8V. Low voltage on UL41 cathode indicates no anode or screen current. This may be down to the low heater voltage reducing the valve's emission. Try this. Switch off. Pull out all the valves. Measure the resistance to chassis of each heater pin. (The brown wires). All bar two pins should read infinite resistance or open circuit. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.