KWS-1 Power Supply Restore

I replaced these three paper capacitors and the selenium rectifier with new components:

I used a 1N4007 silicon diode for the old rectifier and used its post to hold a 3 lug terminal strip. I double checked the schematic – just to make sure I got the polarity correct.

The next part is a little bit tricky – but no real big deal. This is because rather than replace the two aluminum (2 section) electrolytic “can” capacitors, I’ll just use four 47 uf electrolytics and tap into the existing ground:

Tomorrow I will move the wires. The two posts on each old electrolytic are the positive side of each 2 section capacitor – so I put the negative of each new cap on a 3 lug terminal strip on the center post – which is screwed into the existing bolt, an the positive sides on the outer two lugs of the terminal strip. I also that one resistor to move as well. I have new new ones as well – so whatever is easiest, I’ll do that.

I saved at least $500 by restoring the power supply myself – shipping alone would have been hundreds of dollars because it would hve to ship freight. While Howard Mills will have restored both my 75A-4 receiver and now the KWS-1 transmitter, and each was completely restored – new powder coating and silk screening, The power supply is not nearly as critical – because not much of it will even show in the shack:

So, yeah its a bit manky looking, but I’m not a collector per se. It actually would be easy to take the cabinet apart completely and send it to a local powder coater, but then there is the silk screening of the letters – nah – not worth it.

OK –  tomorrow I will wrap it up and turn it on and cross my fingers for a successful “smoke test”. Then it will be ready and waiting for the KWS-1 to return – I’m counting before the end of this month.

2 Comments on “KWS-1 Power Supply Restore

  1. Did you save the old paper caps? You can melt the wax out and hide the new caps inside, if you’re that anal-retentive…


    • I’m not a collector, so I don’t care. But I have seen those who do care about that “perfect” restore.


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