See post above . Also I just noticed the original fets for the power supply were IRFP1405.
Before I realized this I soldered all new fets I the amp which are IRFP064N .
Should I be ok with the IRFP064N’s?
Before I realized this I soldered all new fets I the amp which are IRFP064N .
Should I be ok with the IRFP064N’s?
Use both scope channels. One probe on the leg of an output transistor that connects to the output filter inductor. The other probe on the rail voltage (rectifier output leg). See video attached.
http://www.bcae1.com/temp/ampstartup01.mkv
If the 1405s failed, at the very least, the protection circuit wasn't sensitive enough to shut the amp down before the PS FETs were damaged. Under stress (amp hot, shorted speaker, shorted output...), the 064s would likely fail where the 1405s might survive.
http://www.bcae1.com/temp/ampstartup01.mkv
If the 1405s failed, at the very least, the protection circuit wasn't sensitive enough to shut the amp down before the PS FETs were damaged. Under stress (amp hot, shorted speaker, shorted output...), the 064s would likely fail where the 1405s might survive.
Ok I’m still going through this amp .
Out of 5 banks of outputs 2 banks survived.
Wondering could I use these outputs that survived in 2 of the banks or should I toss them all and order all new ones ?
When measuring them all of them read 2.5M ohms from drain to source
Out of 5 banks of outputs 2 banks survived.
Wondering could I use these outputs that survived in 2 of the banks or should I toss them all and order all new ones ?
When measuring them all of them read 2.5M ohms from drain to source
I would use all new FETs.
Don't throw the surviving FETs away. They can be used for testing.
2.5M one way and open with probes reversed?
Did you short the FET gate to source, when testing?
Don't throw the surviving FETs away. They can be used for testing.
2.5M one way and open with probes reversed?
Did you short the FET gate to source, when testing?
2.5M one way and OL the other way .
No I didn’t short hate to source when testing I will go back and short gate to source and recheck
No I didn’t short hate to source when testing I will go back and short gate to source and recheck
Shorting gate to source is only important if you don't read an open in one direction. This is because the gate can charge and cause the FET to conduct, unexpectedly.
Is there a common issue with these large amps as to why it blows the faces off the outputs ? I can’t find anything wrong with this amp besides blown outputs driver ic’s and power supply fets
The faces get blown off because the amp stores so much energy in the rail caps. When something goes wrong and they try to shunt all of that energy, the die simply explodes.
Did you confirm that the mute delay was working?
Did you confirm that the mute delay was working?
Order the cheap probes from ebay. 4 for $20. They work perfectly fine for audio. When you get down to 2 probes, reorder.