Is there a schematic available for these style amps? Ive seen a few this style, and all needed service around the drive/regulation circuit, 27v Zener diodes I believe. This one amp does not however and so this is a new issue for me.
What this one has is a problem with either RCA shields or secondary ground float. The RCA shield LED blinks rapidly no matter the source (Common, grounded, floating), and the output on speaker terminals passes audio but is jumping all around. I believe this amp also blew a 12" subwoofer, and may have been sliding around in a trunk at some point.
I've cleaned and tested ALL switches, cleaned all potentiometers. Treated with Deoxit all daughter board connections. Rail voltage looks good, regulated voltage looks good. There are no damaged visual areas and all components seem tight. I pressed and tapped on a LOT of components and no change at output/RCA led.
RCA shields to non-bridging terminals is 0-ohms.
Either ^^^^ to amp ground is 1k.
Thank you in advance
What this one has is a problem with either RCA shields or secondary ground float. The RCA shield LED blinks rapidly no matter the source (Common, grounded, floating), and the output on speaker terminals passes audio but is jumping all around. I believe this amp also blew a 12" subwoofer, and may have been sliding around in a trunk at some point.
I've cleaned and tested ALL switches, cleaned all potentiometers. Treated with Deoxit all daughter board connections. Rail voltage looks good, regulated voltage looks good. There are no damaged visual areas and all components seem tight. I pressed and tapped on a LOT of components and no change at output/RCA led.
RCA shields to non-bridging terminals is 0-ohms.
Either ^^^^ to amp ground is 1k.
Thank you in advance
Secondary ground does jump with audio.
Audio does pass, bit distorted because of the jumping.
I pulled the board out of sync and all problems disappeared that is until I plugged in the LED board; then the problem came straight back out of the sync. I lifted R19 which connects to the RCA-Fault LED and the problem disappeared again. Amplifier actually seems to be FIXED with R19 lifted.
R19 leads to D79 and Relay1 Pin1 which is a G6H-2 relay, and pin1 appears to be part of the magnetic portion of the relay. I lifted D79 and it tested fine off the PCB but removing it with R19 in and the problem came back. D19 is connected between Pin1 and Pin 10 of the relay. I'm not totally sure even; why this is all connected back to Relay1. Resistance between pin1-10 of the relay is 180ohms which matches the datasheet.
Relay datasheet: https://www.farnell.com/datasheets/701689.pdf
Audio does pass, bit distorted because of the jumping.
I pulled the board out of sync and all problems disappeared that is until I plugged in the LED board; then the problem came straight back out of the sync. I lifted R19 which connects to the RCA-Fault LED and the problem disappeared again. Amplifier actually seems to be FIXED with R19 lifted.
R19 leads to D79 and Relay1 Pin1 which is a G6H-2 relay, and pin1 appears to be part of the magnetic portion of the relay. I lifted D79 and it tested fine off the PCB but removing it with R19 in and the problem came back. D19 is connected between Pin1 and Pin 10 of the relay. I'm not totally sure even; why this is all connected back to Relay1. Resistance between pin1-10 of the relay is 180ohms which matches the datasheet.
Relay datasheet: https://www.farnell.com/datasheets/701689.pdf
Without a diagram, it's going to be difficult to offer suggestions.
Did you see if the amp would have the same symptoms when the relay is out of the circuit?
Does it do it with no load on the amp?
Did you see if the amp would have the same symptoms when the relay is out of the circuit?
Does it do it with no load on the amp?