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Old 20th October 2019, 01:31 AM
YummyFuzz YummyFuzz is offline
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Join Date: Sep 2019
Location: Perth, Australia
Posts: 10
Default Re: KEL84 from the recycling centre

Hello,

In my first test of my refurbished KEL84, the four EL84's lit up, but not the ECF80's. A quick test showed that there was no heater voltage. I've now fixed this (dry joint), but the DC voltage is reading 8.54Vdc, and given that the ECF80 wants 6.3Vdc, I don't want to proceed in case this damages them.

My setup is that I have the PCB out of the enclosure, no valves, with only the heater AC supply connected. I get 6.3Vac between the transformer white wires, and 3.1Vac if I measure between either white wire and ground. I get 8.54Vdc on the BR1 +/- side and at the V1/V2 heater sockets. BR1 tested in isolation seemed fine, and I replaced C22 with a 4700uF 16V instead of the 10V.

Is this normal/acceptable, or do I need to take steps to drop this voltage with some resistors or diodes?
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