[Hammarlund] SP-600 Advice/Help

[James A. (Andy) Moorer]

----- Original Message -----
 >
> I have started restoring my first SP-600. It's an SP-600-J-3, S/N 5001.
> During the visual inspection I  noticed that the Power Supply area had
> indications of over heating. Terminals 13 & 14 on T8 were very black.
> T8, L51 & L52 were removed. The bottom cover of L51 was out bulged and
> broken away from the case. A small amount of tar had leaked out. L51
> resistance was 155 Ohms, required 155. L52 measured 364 Ohms, required
> 354. The required is what is printed on the chokes. On the schematic the
> resistance for L51 is 170 Ohms. L52 is 440 Ohms. Transformer T8
> resistances appear to be normal Resistance to case on chokes and the
> transformer are at infinity.
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Your SP-600 has all the signs of one I did last year. If you look at the
schematics, you will see that C164 and (I think) C165 and C162 are BBOD's
that are directly from the choke output to ground. If one of those shorts
out, it takes one or both of the chokes with it, and sometimes takes the
power transformer as well. It is a real mess.

The moral of this is NEVER, NEVER, NEVER power up an old un-recapped SP-600
without replacing those capacitors, or at least disconnecting them.

James A. (Andy) Moorer
www.jamminpower.com