THAT would be hard to do anyway, since he has "an Alpine 3545 that blows all 3 fuses almost right away"
The originals aren't likely available.. The FJA4213 and FJA4313 should be good subs for the NPN and PNP output transistors. Order both.
Order from digikey or mouser.
If you desolder the 3 that appear shorted, you should find only one shorted. If you reinstall the other two, you should be able to determine if there are other faults.
Order from digikey or mouser.
If you desolder the 3 that appear shorted, you should find only one shorted. If you reinstall the other two, you should be able to determine if there are other faults.
I removed the one output transistor and the other 2 check out fine now. I put in a 15 amp fuse and left the bad transistor out. I powered it up but it makes a low sizzle sound but powers on. Didn't want to apply power long with that noise or is it ok to keep it powered with the bad transistor out. Lmk thanks
Everything is screw in tight except of course the one bad transistor I removed. I am just using a 12v car battery because I don't hav3 a power supply. I did only use one 15 amp fuse in the amp. I didn't like the hissing noise so I only hooked it up for like 10 seconds but it didn't blow a fuse like before.
It could have some bad capacitors. Suspect any with a brown residue at its base. The ones on the vertical board in the center of the amp are commonly defective. You can slide a piece of thin card stock like that of a business card under the caps to look for residue of leaked electrolyte. Thanks to Cecil for that idea.
Heating the terminals is another option but it risks bridging solder which could be difficult to find if it happens. If the caps have electrolyte leaking, the heat will release a fishy or anti-freeze like odor.
If there is a power supply adjustment procedure in the service manual, that should be done.
Heating the terminals is another option but it risks bridging solder which could be difficult to find if it happens. If the caps have electrolyte leaking, the heat will release a fishy or anti-freeze like odor.
If there is a power supply adjustment procedure in the service manual, that should be done.
The leaked electrolyte is conductive and can bridge between circuits, causing all sorts of problems. Losing electrolyte also reduced the capacitance which can cause problems.
After adjusting the power supply voltage, you may want to try adjusting the bias for the output transistors. Too little bias could make the power supply a bit unstable. If you adjust the bias, turn the pots very slowly while watching the meter. Adjusting by watching the current draw is sometimes easier but requires a series connected amp meter in the B+ line.
Example:
http://www.bcae1.com/temp/ausettingbias.swf
After adjusting the power supply voltage, you may want to try adjusting the bias for the output transistors. Too little bias could make the power supply a bit unstable. If you adjust the bias, turn the pots very slowly while watching the meter. Adjusting by watching the current draw is sometimes easier but requires a series connected amp meter in the B+ line.
Example:
http://www.bcae1.com/temp/ausettingbias.swf
That's likely a fixative. It can sometimes become conductive AND corrosive but it's generally gooey/soft when it's going to be a problem. Set your meter to ohms (highest range if not auto-ranging) and place the meter probe on it, as close as possible, without them touching. The meter reading should not change from what it reads with open probes.
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