Saturday, November 4, 2006

Honey, what's that smell?

"Um, nothing dear.........."

I replied, pulling the power cord on the power supply I was trying to revive.

I had the power supply 90% operational, the only thing I was having issues with was too little on the 5V supply. So, I was re-checking the the voltages using little pieces of wire in the Molex jacks, when I accidentally shorted the 25V supply go ground. Urgh!! !


That smell which wasn't really there was the bouquet of a young 5 watt Mills resister starting to melt it's protective cover.

Now, the PS is 30% operational. I have 15V, but no 25V or 5V coming out of this thing. I could probably get it working again with some generic replacements, but for some reason I don't have a single NPN transistor in a TO-92 case in the house. I guess it's time to order from Mouser again, and I might as well order more power resistors from Parts Exchange, if I'm going to be smoking what I have.

I can't find a source for the BD 419. I can find close matches, but most of the modern replacements have a center collector, which make them hard to retrofit. At this point I feel lucky just to have found the general specs for it. In case anyone can help find a replacment I am looking for:


  • Pins: EBC
  • Power: 2W
  • Hfe: 60
  • Vce 100
  • Through hole, so TO-220 or TO-202

On the other hand this may be a sign from Eutectic, the God of Solder, to design a new power supply board. I may very well end up with the single most expensive Tandberg 3001 ever. :)

More later!

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