HFI1500D Power Fets Blow After Remote is Disconnected

[djeokis]

Looking for help on my HFI1500D Amp. The amps turns on normal, no over heating no current gain, just fine, once i disco the remote, my power fets blow. Amp is using IRFZ44N for the power. Nothing happens to the audio. It only blows the ones from the Power Terminal side.
I have replaced the transistors from the driver module and the OP amps. ( 1D, P2D )

Any help will be appreciated.
Thanks

 

[Perry Babin]

If you don't get any answers, post a photo of the entire power supply section and another of the PS control section.

 

[djeokis]

Here are some Pics

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[Perry Babin]

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[djeokis]

 

[Perry Babin]

They're not posted correctly.

 

[djeokis]

 

[djeokis]

Here is a pic of the whole amp. My apologies for previous posts..

 

[Perry Babin]

Do you have a scope?

Did you check the value of the gate resistors to confirm that they're within tolerance?

 

[djeokis]

Yes. I do.

 

[djeokis]

yes, 47ohms

 

[Perry Babin]

Did you confirm that the drive signals were identical on both banks of PS FETs?

This will be more reliable if the FET locations are loaded.

Did you try removing the B+ and remote together to see if the FETs would survive?

 

[djeokis]

Yes, both signals are identical. If i disconnect both, remote and B+ the amp survives, if i only disconnect the remote, with the power supply i have, it's only burning one FET at a time, if take it to my vehicle, it blows all 5 FETs at once when removing the remote.

 

[Perry Babin]

You'll have to remove the PS FETs and clean the solder pads.

Monitor the DC voltage on terminals 3 and 4 of the PS control IC carefully when the remote is removed. Set the scope to 2ms and about 1v/div. When remote is removed, does the voltage on either terminal go negative?

 

[djeokis]

Removed FETs and cleaned pads / B+ 15v / Terminal 3 = 15V / Terminal 4= 14.39V /
None went negative after removing the remote signal.

 

[Perry Babin]

3 and 4 can't be at those voltages.

You need to monitor with your scope. The meter isn't likely to be fast enough to catch any negative pulse.

 

[djeokis]

Pins 3 and 4 from IC 7500? ... i was measuring terminal post 3 and 4 from the module.

 

[djeokis]

I measured Pins 3 and 4 / Pin 3 has no pulse. / Pin 4 shows a negative pulse after removing remote.

 

[Perry Babin]

It's probably being used for a softstart and that can cause the problem you're having.

Is the voltage on pin 12 dropping to 0v IMMEDIATELY when remote is removed?

 

[djeokis]

If that were the case, IC gone bad? Measured pin 12, voltage drops to 0.35v then starts to drop down when remote is removed.