B&K 1635 AC Power Supply Rebuild


This project was spur of the moment and didn't take very long. While waiting for my Hallicrafters S-38 Shortwave to arrive I was just going through and cleaning the dust off my equipment and calibrating. This AC Power Supply also came from the basement of the TV repair shop I owned back in 92. It worked but the metering volts/amps button was pushed into the unit and the meter did not work. But it did produce a variable AC output. I figured I'd open it up and try to fix it and ultimately decided to go ahead and just strip it down and rebuild it. Nothing better to do, right?


Here it is before I started. Upon close inspection it was obvious why the push button was pushed into the unit and the meter did not work. One of the meter leads was broken off the circuit board and the whole circuit board was was loose in the chassis. The board spacers and the hardware was all missing. Again, what a wiring nightmare (again by my standards). I completely took the unit apart down to removing all the components from the circuit board. Since I did not have a manual I had to first figure out the circuit schematic which wasn't difficult as there really isn't that much to it. I washed the whole thing up and checked all the components and then started reassembly.


Here's the after shots. I discovered that several of the diodes on the circuit board were NTE parts leading me to to believe it was repaired at one time and that is possibly why the board was loose. Problem I guess was after the repair it was not reassembled completely, what a shame because it's a nice little piece of test equipment and it worked! I did replace the on/off switch only because I didn't like the one that was on there. I calibrated it and it's now a very nice addition to my bench.





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