Those appear to be the 0.04 ohm. They are typically on the P-channel FETs in older amps. The 0.02 are on the N-channel FETs.
At no load or very low levels, maybe. You may have some 0.1 ohm emitter resistors. You could parallel multiple if you need to test at higher levels.
For testing, You can use two 0.1s in parallel. That will get you to 0.05. You need to use the proper resistors for the final repair. In applications like this, even the lead length is critical.
I replaced the resistor with the correct value and replaced the outputs also .
Amp will play clean audio but when I increase the volume on the head unit the amp will go in and out of protection mode.
It does this even with no load
Any ideas what might cause this
Amp will play clean audio but when I increase the volume on the head unit the amp will go in and out of protection mode.
It does this even with no load
Any ideas what might cause this
Last edited:
Still can’t figure this amp out if checked a lot of components and the amp still does the same thing audio sounds like garbage and if I try increasing the input level the amp goes in and out of protection mode even without a load
Yes positive rail voltage is present .
I think I might have a problem though
On half of the outputs the drain on the outputs Reads 0 volts the other half of the outputs it reads -37 volts on the drains
I think I might have a problem though
On half of the outputs the drain on the outputs Reads 0 volts the other half of the outputs it reads -37 volts on the drains
The source legs are the rail legs. The drains are the output. This is essentially the amp that you have:
http://www.bcae1.com/temp/bp1200p1_sm.pdf
http://www.bcae1.com/temp/bp1200p1_sm.pdf
Yes I have 57 volts of rail on the source legs but also have 38 volts on the drains of half of the outputs
This isn't a tiny simple amp. You're going to have to be more precise.
Are you saying that you have positive 57v on all source legs? If not, list the circuit board designations of one from each group for the ones with positive and negative rail?
The same thing when giving the drain voltage on any FETs.
Are you saying that you have positive 57v on all source legs? If not, list the circuit board designations of one from each group for the ones with positive and negative rail?
The same thing when giving the drain voltage on any FETs.
I will get back to you on this amp .
I have to order new outputs for it since some are leaking . I replaced the ones in parallel the first time around . But it appears I overlooked the others since they tested fine in circuit
I have to order new outputs for it since some are leaking . I replaced the ones in parallel the first time around . But it appears I overlooked the others since they tested fine in circuit
Ok I removed all of the outputs and some were bad .
How do I check the drive signal on the outputs with them removed ?
How do I check the drive signal on the outputs with them removed ?
I don't have anything on that board, specifically. On the board below, you can see that terminals 13 and 14 were previously solder bridged. Confirm that those pins on the corresponding IC on your board are the same and bridge them. If it's the same, you should get a 50% duty cycle drive on all outputs.
