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cyclopsitis
Nobel Prize Winner
Canada
732 Posts |
 Posted - Jan 03 2007 : 6:21:43 PM
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What type of amp is it? What are the symptoms? Need more info!
Anyway for the PS.
Caution: The following tests are done with out power connected! I'm not sure of your experience with electronics or repairs but if you don't know what you are doing do not take it apart and do NOT test with power connected if you don't know what you’re doing.
1) Check for "cold" or bad solder joints (9 or 10 repairs I have are a direct cause of this if you shine a light on them you should see a hair line crack around the solder joint. Just re-heat them and touch a little new solder to the joints.
2) Check for any burnt, cracked, or over heated parts.
3) Check all physical parts like switches, fuses, breakers, and power cords (because switches move every time you turn them on or off sometimes they can become faulty. Fuses may be burnt out but show no physical evidence) Test the cord I had one amplifier come to my house a few years ago it had been to 2 other repair guys in my area and none of them found the problem I busted my butt over it for a few days and finally notice that cord had a slight kink in it near the "strain reliever" I tested for continuity and the white wire was open... That is the only time I’ve experienced this so it’s not likely unless the amp is old or constantly being moved from one place to another without any thought of the cord being twisted over and over again.
4) Test the transformer. All transformers have some internal resistance if not it would be a short circuit. Test the Primary and secondary. If they have infinite resistance then you have an open circuit that means your T is faulty.
5) After this your onto power diodes or a bridge rectifier... you can use a diode checker for it. Or a good continuity checker it will only conduct one way. If it doesn’t conduct at all its open if it conducts both ways it’s bad as well.
6) Test any regulators in the circuit.
I've never had any problems go any further in a PS then that. You should not need to energize the circuit to find the problem in the PS! If you still can't find the problem after these basic steps then I don't know I'm not there...
As for the amplifier part we need more info to help.
I hope maybe this will get you started. Either way if you have little or no experience MAKE SURE IT IS NOT ENERGIZED and NOT plugged into the wall! It only takes less then a 100ma to kill and these power supplies usually have fuses rated at 2 or 5 amps and that is more then enough to kill so be careful!
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