Willy, I hope that the seller did not send the amp with the tube in it. That would account for that bent plate, unfortunately, and the tube is not repairable. You will need a new 3-500Z.
You can test the HV and the HV metering with the tube removed. All of your HV will be on but not connected to anything except the meter.
Any linear power supply that is designed for 60 Hz mains will run warmer on 50 Hz but in modern designs, this is not usually any problem.
I agree with Evan that the grid probably got shorted to the plate.
Good luck with fixing your amp!
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
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On Tuesday, April 8th, 2025 at 4:33 PM, Willy - LU5WE via groups.io <guiye8@...> wrote:
GA, and sorry for this off topic message; working in the above
mentioned amplifier, it's the USA version (no 10m, just 160 ..15), so I
think it's the US domestic version. This amplifier came to my workbench
because the owner fried the 3-500z (see plate structure tilted), fuses,
step start resistor.
Transformer wired with both winding in series (for 220V, 50 Hz in my
country, actually a little higher ... 226V), and the blower in parallel
with one winding. Blower works fine.
Turned on, and on standby I have a steady 2.2 A of mains current. I've
disconnected all secondaries.
All secondaries connected again, about 2900V somewhat flickering plate
voltage, 5.5V filament, and 13.3V (12VDC line). 2.3A mains current.
Is this high current consumption because the iron core, in this
"domestic" amp is calculated only for 60 Hz lines?.
Regards
Guillermo - LU5WE.
