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Old 16th Aug 2019, 11:14 am   #8
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 2,880
Default Re: Pick up and Valve problems

The GZ32 contains two separate heaters - one for each diode. Failure of one heater, obvious by there being only one bright orange spot visible from the top of the valve (if you can see through/round the silver getter), is not uncommon. But for both heaters to fail in the same valve is rare. It can be due to a solder contact failure inside one of the pins on the valve's base. But it may also indicate a failure in the amp's wiring somewhere between the 5V secondary on the mains transformer and the GZ32 socket. If you make any measurements here do remember that this part of the wiring is connected to the GZ32 cathode which, when the valve is working, will be at about 370V DC relative to the chassis !


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