Hello all;
I am in the process of repairing an Alpha 76PA for a friend.
>From initial inspection, I have found the 2 resistors in the step-start (R1,
R2) burned and the Plate choke burned in half. The owner states that the amp
worked fine, took off the top cover to do some dust cleaning inside, and the
dummy powered it up by holding the AC interlock switch on, failing to notice
the high-voltage intelock mechanical switch !!!
I would think (by studying the schematic) that the choke would no be affected
by this act of stupidity, but i can understand the inrush ckt resistors
going. My conclusion is that he fried the plate choke befofe hand, then
opened it up for inspection and then screwed up the step start ckt by failing
to obvserve the hv safety mechanism.
Does anyone know if the plate choke is still available from Alpha, as well as
a good source for the 10ohm/12w chassis-mountable reisistors ??
My next thought is to check the 3 8874 tubes for a short. Any suggestions ??
Anyway, I tried to get to Alpha-power's web site, but no luck today. Does
someone have the current tel # (Dick, are you QRZ here ??)....
Also, has anyone modified one of these to use a newer vintage tube(s) ?
Thanks for any and all suggestions/thoughts..
73 Eric
KK2ED (ex ka2ykc)
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