GM9601 pioneer

[Hexhclass]

GM9601D

This amp powers up,rail and regulated voltages ok.The LED stays on red (protect).
I see no oscillation on the output FETs. At the output terminal 2.108v offset. Someone had already tried to repair it.
Any suggestions?

 

[Perry Babin]

If you touch a speaker or dummy load across the speaker terminals, does the voltage immediately go to 0v?

Does the amp draw additional current when you do that?

 

[Hexhclass]

The voltage immediately goes to 0v

Also it doesn't draw more current.

 

[Perry Babin]

I can't find a (free) service manual. Post a photo of the outputs and drive stage so I can see if it looks familiar.

 

[Hexhclass]

The port near the driver IC ,whats it for?

 

[Hexhclass]

larger pic

 

[Perry Babin]

#5:
You'll have to be more specific.

At the following site, the D9605 SM is available. It uses the same ICs. Maybe it will be of some help.
Elektrotanya | This site helps you to save the Earth from electronic waste!

 

[Hexhclass]

I have oscillation on the outputs now but the amp will start drawing more current causing the FETS to heat up. I want to install caps instead to scope the signal.On what pads should i connect them and what value cap can be used?

 

[Perry Babin]

Do the FETs heat up and cause an increase in current draw when tightly clamped t othe heatsink?

I've never tried using a loading cap in place of the FETs in an amp using this IC. While the IC is readily available if damaged, it looks like it could be difficult to replace.

In most amps, using a cap between 0.01 and 0.1uF is safe but I don't know in this amp.

This appears to be a self oscillating amp. Have you removed the FETs yet to see if it is clocked or self-oscillating?

 

[Hexhclass]

I only see oscillation when the FETs are installed and i insert input signal.
The four transistors near the output seem to be the last thing driving the FETs.
I will clamp it back to the heatsink to monitor current draw.

 

[Perry Babin]

Is the frequency of oscillation the frequency that you're driving into it or something nearer 80kHz?

 

[Hexhclass]

I used music

 

[Hexhclass]

I view the output signal of a working amp and the High side signal dont look good like the working amp.


signal on first and last leg



10v/dv 5/us

 

[Perry Babin]

Are the positive and negative supply rails staying even (one not increasing as the amp is driven into a load)?