I'm looking at a Rockford Fosgate BD10001 that I took in as "working" but needing the remote turn-on tab repaired (torn off trace & vias, etc). It had typical broken RCA shield leads, so I repaired those. When I pulled the board I also found C39 had shorted to the heatsink at some point as well.
The amp powers up and produces audio, but I only have small bookshelf speakers currently available so I can't test to full potential. That said, I was wondering if these are normal for this amp:
Idle current: 1.9A
Speaker terminal DC offset: 0.182V
84.3V between twisted red & black wires
R44 gets hot, transformer gets warm
Speaker crackle/pop with remote connect/disconnect
Constant light speaker hiss/noise regardless of gain position or RCA connection
The amp powers up and produces audio, but I only have small bookshelf speakers currently available so I can't test to full potential. That said, I was wondering if these are normal for this amp:
Idle current: 1.9A
Speaker terminal DC offset: 0.182V
84.3V between twisted red & black wires
R44 gets hot, transformer gets warm
Speaker crackle/pop with remote connect/disconnect
Constant light speaker hiss/noise regardless of gain position or RCA connection
Attachments
The high-frequency noise probably won't be audible with the speakers that the amp was designed to drive.
R44 is large because it's going to have to dissipate significant power. Check C67 but the heating is likely normal.
The cap doesn't look like it was trimmed to the correct length. Cut it. If you're still concerned, install a spacer to keep the board away from the heatsink.
Does pin 7 of U21 switch immediately when remote is disconnected?
R44 is large because it's going to have to dissipate significant power. Check C67 but the heating is likely normal.
The cap doesn't look like it was trimmed to the correct length. Cut it. If you're still concerned, install a spacer to keep the board away from the heatsink.
Does pin 7 of U21 switch immediately when remote is disconnected?
C67 appears good out of circuit (9nF on Fluke 117 and 8.8xxnF on Peak LCR45).
U21 Pin 7 reads
-0.179 immediately at remote connection, jumps to -0.199, settles around -0.191, and drops off immediately at remote disconnect.
If I discharge the caps I get a high pitched squelch/squeal upon first remote connect, then afterwards just the click/pop upon subsequent connections.
U21 Pin 7 reads
-0.179 immediately at remote connection, jumps to -0.199, settles around -0.191, and drops off immediately at remote disconnect.
If I discharge the caps I get a high pitched squelch/squeal upon first remote connect, then afterwards just the click/pop upon subsequent connections.
I'm sorry, I was mistakingly reading U11. Here is what I get from U21:
U21 Pin 7 reads
-0.225v without remote connected
8.56v immediately at remote connection, then drops to -8.44v, and returns immediately to -0.225v at remote disconnect.
U21 powered up reads:
Pin 1: -8.39
Pin 2: 0.053
Pin 3: -8.72
Pin 4: -9.69
Pin 5: 5.043
Pin 6: 7.64
Pin 7: -8.47
Pin 8: 9.93
Pin 6 charges from 0 to 7.64v.
U21 Pin 7 reads
-0.225v without remote connected
8.56v immediately at remote connection, then drops to -8.44v, and returns immediately to -0.225v at remote disconnect.
U21 powered up reads:
Pin 1: -8.39
Pin 2: 0.053
Pin 3: -8.72
Pin 4: -9.69
Pin 5: 5.043
Pin 6: 7.64
Pin 7: -8.47
Pin 8: 9.93
Pin 6 charges from 0 to 7.64v.