I have an American Bass amp here where the power was cycling between power and protect. When I first attach remote power, the relays would engage, and then click out. Then the amp would cycle between power and protect about every 2 seconds.
When I test between the main ground and the secondary ground, RCA shield, or inductors I get 1.49vdc pulses with the amp cycling.
I removed the output driver card. This in turn stopped the cycling. The amp powers up. Pulls no excessive current. PS waves look good. All voltages are present.
When I tested the pads where the driver card attaches, all the voltages look fine. However, when I touch the red probe to pads 3 or 6 of the first bank of the pads for the left side of the driver card, the amp will protect. It shows the voltage then into protect. A reset of the remote, amps back to normal. Its only doing this on the left side bank of pads. When I test the right side pads it doesn't protect...
Any ideas? I'm lost. Never had this happen before.
When I test between the main ground and the secondary ground, RCA shield, or inductors I get 1.49vdc pulses with the amp cycling.
I removed the output driver card. This in turn stopped the cycling. The amp powers up. Pulls no excessive current. PS waves look good. All voltages are present.
When I tested the pads where the driver card attaches, all the voltages look fine. However, when I touch the red probe to pads 3 or 6 of the first bank of the pads for the left side of the driver card, the amp will protect. It shows the voltage then into protect. A reset of the remote, amps back to normal. Its only doing this on the left side bank of pads. When I test the right side pads it doesn't protect...
Any ideas? I'm lost. Never had this happen before.
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O.K. there might have been a lil solder remnants between 2 of the pads. All I did was brush the pads with acetone, look to see where those pads led to... which is the low side banks... checked all the transistors again, hooked power back up and now it doesn't kick into protect when I test pads 3 or 6.
SO, the problem is likely driver card somewhere? Or something in the circuit once its connected...
I have the following voltages on the pads: From left to right:
Pad 1: -82 - -85v
Pad 2: -115.7
Pad 3: 122.5
Pad 4: 0
Pad 5: 0
Pad 6: 123.3
Pad 7: 0
Pad 8: 0
Pad 9: -122.7
Pad 10: -83 tp -85
Pad 11: -127.6
Center
pad 1: 0.2v
pad 2: 14.9v
pad 3: 4.9
pad 4: 0
pad 5: 0
pad 6: -5.1
pad 7: -0.2
right bank of pads
pad 1: -127.9
pad 2: -82 to -85
pad 3: -115.7
pad 4: -123.3
pad 5: 0
pad 6: 0
pad 7: -123.2
pad 8: 0
pad 9: 0
pad 10: -127.5
pad 11: -82 to -85
What should I check next?
SO, the problem is likely driver card somewhere? Or something in the circuit once its connected...
I have the following voltages on the pads: From left to right:
Pad 1: -82 - -85v
Pad 2: -115.7
Pad 3: 122.5
Pad 4: 0
Pad 5: 0
Pad 6: 123.3
Pad 7: 0
Pad 8: 0
Pad 9: -122.7
Pad 10: -83 tp -85
Pad 11: -127.6
Center
pad 1: 0.2v
pad 2: 14.9v
pad 3: 4.9
pad 4: 0
pad 5: 0
pad 6: -5.1
pad 7: -0.2
right bank of pads
pad 1: -127.9
pad 2: -82 to -85
pad 3: -115.7
pad 4: -123.3
pad 5: 0
pad 6: 0
pad 7: -123.2
pad 8: 0
pad 9: 0
pad 10: -127.5
pad 11: -82 to -85
What should I check next?
Ultra: With the output card removed I have no DC on the output terminals. The amp was connected to 10 batteries @ the time it started to do this, and my bench was around 12.5v. When I had the card installed, there was a flash of 0.1vdc on the output terminals between the relays clicking in and out. Then if I put the black probe on the main ground and the red probe on either the secondary center tap, RCA ground shield, or the small filter inductors I was getting a reading of 1.49 volt pulses as the amp cycled.
Perry:
I sent you an email with the driver readings
The solder bridge was desoldering "crud" stuck in the flux from my removing the card. I did look well before removing it for any solder bridges. All I did was use a tooth brush with acetone to remove the flux and some small specks of solder in it. There might have been something in the area I over looked that got removed when I brushed the board.
I rechecked the pads today with card still removed. Things did change ( center bank pad 7). The left and right banks don't seem to be a perfect mirror with these amps. The AB 1100.1 I did awhile back was the same. The big change in the rail numbers I believe is input voltage is 14.4 instead of 12.5.
Left bank
1) -90 to -115v
2) -133.5
3) 144.9
4) 0.009
5) -0.003
6) 145.4
7) 0.009
8) -0.003
9) -147
10) -93 to -113v
11) -147.3
Center (major change to pad 7)
1) 0.228
2) 14.96
3) 4.98
4) 0.009
5) 0.009
6) -5.03
7) -1.5v? This was -0.2 volts yesterday.... if I leave probe on it slowly pulls toward 1v but I gave up @ -1.3v. O.K. not sure why, but if I check this with my canadian tire meter I get the -1.5v if I use fluke clamp meter I get the -0.2v. ???
right bank
1) -148.5
2) -91 to - 112v
3) -137.1
4) 148.7
5) 0.009
6) 0.004
7) -149
8) 0.009
9) -0.011
10) -149.8
11) -90 to -115
I sent you an email with the driver readings
The solder bridge was desoldering "crud" stuck in the flux from my removing the card. I did look well before removing it for any solder bridges. All I did was use a tooth brush with acetone to remove the flux and some small specks of solder in it. There might have been something in the area I over looked that got removed when I brushed the board.
I rechecked the pads today with card still removed. Things did change ( center bank pad 7). The left and right banks don't seem to be a perfect mirror with these amps. The AB 1100.1 I did awhile back was the same. The big change in the rail numbers I believe is input voltage is 14.4 instead of 12.5.
Left bank
1) -90 to -115v
2) -133.5
3) 144.9
4) 0.009
5) -0.003
6) 145.4
7) 0.009
8) -0.003
9) -147
10) -93 to -113v
11) -147.3
Center (major change to pad 7)
1) 0.228
2) 14.96
3) 4.98
4) 0.009
5) 0.009
6) -5.03
7) -1.5v? This was -0.2 volts yesterday.... if I leave probe on it slowly pulls toward 1v but I gave up @ -1.3v. O.K. not sure why, but if I check this with my canadian tire meter I get the -1.5v if I use fluke clamp meter I get the -0.2v. ???
right bank
1) -148.5
2) -91 to - 112v
3) -137.1
4) 148.7
5) 0.009
6) 0.004
7) -149
8) 0.009
9) -0.011
10) -149.8
11) -90 to -115
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