Audiopipe AP 3000 1D

[caraudioguy2100]

So should I reinstall the rectifiers ?

 

[Perry Babin]

Yes. Of course, you have to be careful when powering it up initially. Everything should be OK.

 

[caraudioguy2100]

Reinstalled the rectifiers .

Here is what I get

On 1 bank of outputs

MMBT4403

Collector:5.13
Base:11.17
Emitter:11.50

MMBT4401

Collector:17.70
Base:11.09
Emitter:11.63

Other MMBT4401

Collector 11.16
Base:starts at 5 volts and continues to climb
Emitter :11.70


The other bank of outputs

MMBT4403

Collector -68.8
Base:-63.3
Emitter-63.1

MMBT4401 both of them are the same

Collector:-55.8
Base:-64.1
Emitter:-63.1

 

[Perry Babin]

Is the amp producing rail-rail oscillation on the output FETs?

 

[caraudioguy2100]

I don’t know right before I was about to check it blew the outputs again

 

[Perry Babin]

Were they clamped to the heatsink?

If not, did they possibly overheat?

 

[caraudioguy2100]

They weren’t clamped to the heat sink

It doesn’t matter if they are clamped to hearsink or not it continues to blow the outputs everytime

I had them clamped to heatsink and it blew them twice and I didn’t have them clamped it also blew them twice .

I went thru 8 outputs already trying to track down the problem .

 

[Perry Babin]

Were the two waveforms you posted the high side and the low side?

If so, you may have a defective inductor that's intermittently shorted.

 

[caraudioguy2100]

Yes that is the high and low side both look the same

 

[caraudioguy2100]

Ok I ordered new outputs again and ordered extras also ordered new drivers .

Would a shorted inductor cause the voltage problem I have where there is low voltage on 1 bank of drivers and not the other

 

[caraudioguy2100]

Ok I replaced the outputs, drivers and the output inductor .

This is what I get on all of the outputs both high and low side .

Does the drive signal appear to be correct or do I still have a problem .

Scope settings are 2us 5volts/div

 

[Perry Babin]

2us or 5us? It's probably OK if you have it on 2us but it seems like it's a bit too high in frequency. The shape of the waveform looks OK.

 

[caraudioguy2100]

Sorry it’s 5us

So the first board looks ok

Im gonna replace the outputs and drivers on the 2nd board so everything matches and then check that one as well .

 

[caraudioguy2100]

Replaced the 2N4401,2N4403 drivers for the outputs
Also replaced the output filter inductor and all the outputs and lastly the rectifiers .and the gate resistors for the outputs

Is there anything else I should check before I power this up since I had a problem with the outputs blowing every-time I powered it up .

 

[Perry Babin]

Is the waveform for all of the outputs the same as the last image you posted?

Don't install the rectifiers until you get a good signal on the output gates.

There's still a possibility that you could have an intermittently shorted inductor that will cause the outputs to fail again. If they do or if you see a change in idle current when you twist the inductor, you can deal with that... if it is a problem.

 

[caraudioguy2100]

Yes all outputs have the same wave form as previously posted

 

[caraudioguy2100]

All outputs , drivers, gate resistors for the outputs are brand new .

Amp powers up and idles fine .

I get 73 volts of dc measured directly across the speaker terminals .

Any ideas on where to start looking

 

[Perry Babin]

There are 2 boards. Which one has DC on its output?

 

[caraudioguy2100]

The board with the rca jacks on it is the board that is causing the 73 volts .

I have 73 volts on 1 lead of the output filter inductor

 

[caraudioguy2100]

Do you have a schematic for this amp?