I got this amp with the power supply and output sections both having blown fets. I replaced the fets and now when I power it up the power supply starts fine for the first 3 seconds Drawing .4 amps. But when the output stage kicks on the amp draws current for a tenth of a second and the output side shuts down. And keeps cycling this way
The op-amps are running hotter than the outputs. That's not significant heating through the outputs.
Are you sure that you're not simply starving the amp for current?
Are you sure that you're not simply starving the amp for current?
Im allowing 7 amps to pass. That's usually enough to get small amps like this going.
I know the outputs aren't getting too hot but I don't think the 10th of a second the output section is on for is enuf time to get them to heat up. But it does look like one side is heating slightly more than the other.
I know the outputs aren't getting too hot but I don't think the 10th of a second the output section is on for is enuf time to get them to heat up. But it does look like one side is heating slightly more than the other.
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The amp itself makes a a clicking sound every time it cycles that I can feel when the amp is on my lap. Wonder what that could be since there are no relays in this amp.🤔
How long had it been on in the photo? The op-amps were already hot?
The transformer can sound like that when it has drive problems or when it's trying to drive a bad load (generally a direct short).
What's the PC# on the board?
The transformer can sound like that when it has drive problems or when it's trying to drive a bad load (generally a direct short).
What's the PC# on the board?
Bridge across C2 in the diagram and confirm that the amp is producing both rail and both regulated voltages and that the regulated voltages are within tolerance for the installed programming resistors.
There are two resistors that control each channel. Pull the resistor for the channel that's questionable (R218?) and remove the jumper from the capacitor. Does it power up and does channel with the resistor (R118?) still in place produce clean audio?
What should the regulators have on them?
The 317 has
Leg 1: 13
Leg 2: 14.5
Leg 3 26v
337 has
Leg 1: -12v
Leg 2: -26
Leg 3: -13
The 317 has
Leg 1: 13
Leg 2: 14.5
Leg 3 26v
337 has
Leg 1: -12v
Leg 2: -26
Leg 3: -13
It's not excessive. but the numbers you posted (low resolution, need the exact meter reading) make them look questionable.
When I removed r218 the amp still cycles.
With r118 removed it draws current the instant the remote is applied.
With r118 removed it draws current the instant the remote is applied.
The 317 has
Leg 1: 13.49
Leg 2: 14.5
Leg 3 26.32
337 has
Leg 1: -12.21
Leg 2: -26.36
Leg 3: -13.49
Leg 1: 13.49
Leg 2: 14.5
Leg 3 26.32
337 has
Leg 1: -12.21
Leg 2: -26.36
Leg 3: -13.49