The next thing I would look at is the voltage on pin 5. If there is an electrolytic cap connected between this pin and ground, it may be leaky and is pulling the voltage down. I'd expect the voltage on this pin to be near 2/3 of the voltage on pin 8.
If the cap from pin 5 to ground is OK, the 555 may be defective. Before replacing it, you should trace the resistors connected to pin 5. There may be one from the remote and another to ground.
If you pull the 555, you can short from pin 3 to pin 1 and the amp should power up. This will, however, defeat the protection circuits so you have to be very careful. Insert a 10-15 amp fuse in the B+ line before applying power.
If the cap from pin 5 to ground is OK, the 555 may be defective. Before replacing it, you should trace the resistors connected to pin 5. There may be one from the remote and another to ground.
If you pull the 555, you can short from pin 3 to pin 1 and the amp should power up. This will, however, defeat the protection circuits so you have to be very careful. Insert a 10-15 amp fuse in the B+ line before applying power.
It's unlikely that that type of capacitor would fail but you should pull it to see if the voltage comes up. If it does not, use you ohm meter to find all resistors in that area that are directly connected to pin 5. You will have to read their values from the color code. Reading them in the board isn't reliable. If there is one that connects to the remote and another that goes to ground, we may be able to calculate the voltage that should be on pin 5.
If there is no resistor to ground from pin 5 and only a resistor to the remote line, I believe the 555 is likely defective.
If there is no resistor to ground from pin 5 and only a resistor to the remote line, I believe the 555 is likely defective.
Perry, Once again you're the MAN!!!!! I put a new NE555 in and
boom, It's working wonderfully. Thank you!
I have another question for you. I have a US amp USA 3000 that has burnt fairchild 75344p's on the front end of the amp. I am sending pic's. Anyway I am afraid to do this amp myself because it has a clear plexiglass cover and it needs to look halfway decent. Would you be able to repair it or know somebody you can recommend? that would be fairly resonable price wise?
Thanks!
boom, It's working wonderfully. Thank you!
I have another question for you. I have a US amp USA 3000 that has burnt fairchild 75344p's on the front end of the amp. I am sending pic's. Anyway I am afraid to do this amp myself because it has a clear plexiglass cover and it needs to look halfway decent. Would you be able to repair it or know somebody you can recommend? that would be fairly resonable price wise?
Thanks!
Attachments
I don't want to repair it. Chris at dB-r electronics does good work.
http://www.db-r.com/
Did the voltage on pin 5 come up to 2/3 of the voltage on pin 8?
http://www.db-r.com/
Did the voltage on pin 5 come up to 2/3 of the voltage on pin 8?
pin 5 9.08volts.
Thanks again! I will be looking you up later if you don't mind to help me finish up on that Orion HCCA 275G4 leaking voltage out the speaker outputs. from awhile back. Sent you a bunch of pictures about 4-5 months ago. You may not remember. I got busy and never finished it.
Thanks again!
Randy
Thanks again! I will be looking you up later if you don't mind to help me finish up on that Orion HCCA 275G4 leaking voltage out the speaker outputs. from awhile back. Sent you a bunch of pictures about 4-5 months ago. You may not remember. I got busy and never finished it.
Thanks again!
Randy
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