Soundstream MC140x

[caraudioguy2100]

Does anyone have high resolution pics of the power supply area of this amp ?

Someone has been it before

 

[Perry Babin]

The attached diagram should be the same without the crossover. Maybe it's close enough.

 

[caraudioguy2100]

The amp has MTP25N06 for the power supply fets with 47.5 ohm gate resistors

Does anyone know of a good replacement for the fets ?

 

[Perry Babin]

The drive circuit is weak. A Z44 may be the best you can use. You'll need to confirm that the FETs don't heat up significantly at idle (at full duty cycle).

 

[caraudioguy2100]

The diagram shows C4 as a 2200uf cap .

When I opened the amp up it had a 3300uf cap but someone worked on it before and who knows what all they did .


Wondering should I use the 2200uf cap or the 3300uf cap

 

[Perry Babin]

3300 won't be a problem but there are other specs like temperature and voltage that can make a difference.

 

[caraudioguy2100]

Replaced the fets gate resistors a few caps cleaned the board up .

As soon as I apply remote voltage the amp blows the 20 amp fuse and the fets get hot within a sec .

Are the fets driven off the 3524 in this amp ?

 

[Perry Babin]

Yes. Are the 150 ohm resistors within tolerance?

Yes, the 3524 drives the FETs, with the help of the 150 ohm resistors.

 

[caraudioguy2100]

The 150 ohm resistors are brand new and within tolerance

 

[Perry Babin]

If the drive signal, without the FETs, is good, the transformer could be shorted.

 

[caraudioguy2100]

I removed the rectifiers and the power supply has perfect drive signal .

So either the rectifiers are shorted or something in the output section is bad

 

[Perry Babin]

You can check the rectifiers.

Have you eliminated the transformer as being intermittently shorted?

You can remove the 3a fuses to eliminate each channel as the possible culprit.

 

[caraudioguy2100]

I find one of the rectifiers to be shorted .

Now the fun of trying to find one or something I can use for a replacement since this amp uses the doublers

 

[caraudioguy2100]

I found a rectifier for the amp .

Channels 3/4 work correctly

Channels 1/2 have no output I cleaned the switches and when switching them back and fourth I can hear a low thumb through the test speaker when switching them back and fourth but still no output

Are there muting transistors in this amp or any ideas ?

 

[caraudioguy2100]

I found a shorted output in 1 of the channels after testing and the fuse blew .

Wondering is there a good replacement for the

TIP106 and TIP101 ?

 

[Perry Babin]

TIP102 and TIP107?

The originals are readily available.

 

[caraudioguy2100]

Yeah I can use tip102 and 107 for the the tip101,106

Just been a long day can’t think