Ok so I just got a Memphis in and it had a blown power supply. I replaced all those fets and checked the output fets. All seemed well. Until I install the rectifiers the power led just kind of flickers? And it never really starts up should I power it up with a larger supply. It draws 9.45amps when it fails to start up. No relay clicks nothing.
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The output section has 9 irf9640's and then 5) irf640's this does not seem correct? What output transistors should be run in the output section of the amplifier?
I had this problem and didn't find a proper solution, although I got the amp working.
This may be risky but it didn't cause any problem when I did it.
Using a small wire (strand of computer ribbon cable), you will jump the driver transistor (Q4A) base to the secondary ground (use pin 1 of the 7909 (U4) in front of the driver board). Solder the wire to the base of Q4A. Hold the jumper on pin 1 of the 7909 for a fraction of a second after remote is applied (just time for the rail caps to charge) then lift it.
Does the amp power up and produce audio if you do that during startup?
This may be risky but it didn't cause any problem when I did it.
Using a small wire (strand of computer ribbon cable), you will jump the driver transistor (Q4A) base to the secondary ground (use pin 1 of the 7909 (U4) in front of the driver board). Solder the wire to the base of Q4A. Hold the jumper on pin 1 of the 7909 for a fraction of a second after remote is applied (just time for the rail caps to charge) then lift it.
Does the amp power up and produce audio if you do that during startup?
Perry I'm going to change the output transistors to the igbt transistors. Any of the resistors need to be changed?
Not igbt ok. so those are the only transistors I have that are the B31N20D which model did you use I do have fb52n15d that are n channel. So basically I'm just using all n channel mosfets?
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An IGBT is a completely different animal.
With class D, you really never know unless you try them.
With class D, you really never know unless you try them.
Maybe irf4227 then I can try them. I will order the FQP32N20C I think they are the closest I been able to find. Should I just start with a few in the amplifier or all of them?
Have you tried the 'fix' I emailed you about?
If you replace the FETs, you could run into reliability issues for problems that don't show up on the bench.
If you replace the FETs, you could run into reliability issues for problems that don't show up on the bench.
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