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Old 1st April 2009, 02:22 PM
MrKettle MrKettle is offline
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Join Date: Jan 2006
Location: Warwickshire
Posts: 68
Default Another WD88VA build

Well, I am currently part of the way through building a standard single input version. Have just got to the point of plugging it in for the first time to test the PS voltages, and thankfully all of the blue smoke stayed in the wires and the fuse didn't. Thoughts so far:

The DC heater voltage measured with my meter is quite high (c. 8V). I take it that this will drop when the small signal valves are inserted?

Heater wiring: the measured lengths of cable for the KT88 heaters are quite tight when twisted, but the supplied amount of grey cable seems to be only just sufficient for that and the link between the bridge rectifier and the voltage divider on the HT power supply tag board. A little bit more wire would enable a bit of slack at either end of the wiring which could help with routing.

Bridge rectifier: call me an idiot but I didn't notice that the rectifier had pinout details moulded in the body until I found technical details on a website. I suspect there may be a case for a pinout diagram in the instructions.

And on to the rest of the build....
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Old 1st April 2009, 03:21 PM
John Caswell John Caswell is offline
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Join Date: Dec 2005
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Default Re: Another WD88VA build

Well Mr Kettle
Well done so far.
Correct. DC heater voltages will be high until the valves are inserted.
The wire between bridge and voltage divider can be any old wire as all it is doing is providing a potential to "stand off" the heaters to avoid heater cathode breakdown, but I am sure Peter/Andy will take note of this.
Bridge rectifier mmmmm yes, usually the "odd" out of line terminal is the positive, the opposite corner the negative, and the other two AC in.
Any problems write it here and someone will help sort it out

John - Dr John
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