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FRED
| | Posted on Sunday, February 02, 2003 - 7:44 pm: | 
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I was straiting up the shack and unplugged my power supply. It a PS 46K. When I plugged it back up and turned it on I noticed a frying sound. I think it was the transistor on the borad where you can adjust the voltage on the inside. It still seemed to work but the chord that plugs in the wall got real hot. I unplugged it. What do I do? |
Bigbob
| | Posted on Sunday, February 02, 2003 - 10:40 pm: |
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All the sounds I heard like this was a frying transformer or a bad filter cap,a filter cap makes that noise then BOOM,if the transformer primary winding is unfused you'll either have a fire or flip a breaker or blow a house fuse.Check your primary with a ohm meter,it should show between 3 and 7 ohms of resistance,if it's shorted it will show 0 ohms,but by all means take it to a tech to be sure. |
2600
| | Posted on Monday, February 03, 2003 - 12:54 am: |
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People will ask us "Do you fix power supplies?". The standard answer is "Not many, but we do a lot of autopsies on them". This kind of failure is what makes the more expensive Tripp-Lite and Astron power supplies look attractive. Pyramid is a brand name, like "Sears". They buy from more than one supplier, so not all Pyramid supplies are alike. They will work well until they fail. When they do, the "laundry list" of parts that get damaged gets pretty long. From your description, I would predict that the "crowbar" SCR and zener diode are bad, the TIP41C "driver" transistor on the circuit board, the 723 chip and at least one of the four output transistors will check bad if you unhook and test them. Ever heard the phrase "Domino Effect"? By the time all that stuff gets put into the thing, you are well past half the price of a new supply. If you miss finding one bad part that stays in the unit, and fire it up with a bunch of new parts, that ONE bad piece can fry your new parts in a hurry. And yeah, I just hate it when that happens. You would, too.
73 |
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