[AMPS] Alpha 374A kaput
David B. Ritchie
dbr@alumni.caltech.edu
Mon, 12 Jan 1998 13:13:59 -0800 (PST)
There are three ceramic resistors to worry about and they can all test
good when cold -- the problem is that when they heat up, they open up.
The first is the 10k -- that shouldn't burn the fuses -- it should just
cause the step start power supply to fail and bouce the amp to off. The
ones that will pop the fuses are in the step start circuit as I recall --
take a look at these -- I believe there are a pair, one for L1 and one
for L2 (each side of the 220). Whatever you do, do not put bigger fuses
in -- this will temporarily cure the problem so that more stuff can blow
up down stream!
Good luck
Dave N7UE
On Sun, 11 Jan 1998, Matt Trott--K7BG wrote:
> When I switch on the 374A it immediately blows the fuse(s). I think the
> last time this happened I was pointed to the 10K ohm resistor just in front
> of the xfrmr. I replaced that opened resistor a year or more ago and the
> amp has run great ever since until today. I just checked that resistor
> again and it is fine. So now what??
>
> Duh appliance operator who likes to fix his own equipment. Any suggestions
> on what the cause may be??
>
> Thanks, Matt--K7BG
>
> P.S. Thanks to those who pointed me in the right direction for the Heatkit
> parts.
>
>
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David B. Ritchie, Esq.
D'Alessandro & Ritchie, P.C. Intellectual Property Lawyers
1731 Technology Drive, Suite 700, San Jose, CA 95110-1312
408-441-1100 (TEL); 408-441-8400 (FAX); N7UE@ALUMNI.CALTECH.EDU
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