I snagged three Astron power supplies recently from a listing on Craigslist. It was quite an inexpensive buy, but they were heavily abused and needed some repair, so overall, it won’t work out to a huge profit, but it gives me an opportunity to apply some skill and come out on top.

The previous user, I’m told, was a car-stereo seller and used the Astrons in a large display of car stereos.

From the group, there was a 35-amp RS-35A which, after testing, appeared to be in fine shape; only the fuse was out of order – the previous user had replaced the 8A ceramic fuse with a 10A glass, 3AG fuse – both incorrect and unsafe. The large value would allow more current to be drawn than what it was designed for; ceramic fuses are more resistant to breaking given the high current. Replaced the fuse, tested the supply for regulation under load and it’s now powering my FT-897D.

The two others, both RS-50A models were substantially abused and showed signs of having been run well over-current and for longer than the 50% duty-cycle.

But both still provided regulated voltage!

Both had incorrect fuses – replaced both with correct 10A, ceramic fuses. One had a 20A, 32V fuse (on the 120V primary!). Both had burned wires and the large filter caps (100,000uf in one and two 51,000uf in the other) were toasted.

Astron supplies replacement parts, so I’ve already repaired and tested the newer model with the single 100,000uf cap. Now waiting for two 64,000uf caps to repair the other. I had to make replacement 13.8-volt ‘common’ cables with black, 10ga wire. That ought-a hold ’em.

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