[Hammarlund] Another SP-600-JX-17 lives!

[Russ WQ3X]

Hi all -

Just got this SP-600-JX-17 s/n 14266 beast recapped (un-black-beauty-ized)
with the help of the article by W2EC, Ray, and the wise words of advice from
Roy Morgan who said it MUST be done. There were 56 of the ugly critters. 25
of them were cracked and the best ones measured 250K on my 500V megger. Some
were down to 50K. I also replaced two cooked resistors which were likely due
to the caps breaking down. This makes a strong case for changing out the
black beauties in any SP-600 that still has them. I don't think it is a good
idea to even try out a receiver that still has the BBoDs.

I did try the receiver when I first got it and it did come on but the top
half of all bands was gone. (That's when Roy told me I had to change the
caps.) Now it works well and sounds good on all bands. I'm surprised at how
well it works even on SSB. The tuning is sooooo smooth. I also rebuilt the
filter cap can and probably will do the .05 and 5 10uF cans before I quit.

I found one quirk that I wonder if anyone else has seen.... When in the CW
mode, the S-meter moves up about 1/4 to 1/3 scale like it is responding to
the BFO injection signal. I see some of the other models had a 1K BFO
injection adjustment pot but the JX-17 has a fixed 100 Ohm resistor in the
cathode of V12. The AVC works fine on AM but the added signal from the BFO
buffer V12 when switched into the CW mode seems to be enough to make the AVC
diode conduct. Is this normal?

Thanks for all the recent posts about recapping that finally made me start
this project. It seems like a lot of work and it is! And a lot longer than 2
evenings! Their were all sorts of other things to fix that I found during
the recapping but as everyone says, it's worth it.

73, and Happy New Year,

Russ WQ3X