Punch 40 DSM

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seankane

seankane

Member
Joined 2010
Punch 40 DSM PC-0001-A REV A

I have a punch 40 dsm I am working on and it has no output. It came in with a burned up power supply. I repaired the power supply and all is well with that.

The amp is producing 46.1 vdc rail voltage

The op-amps have positive and negative voltage of 11.61 vdc on pins 4 and 8.

The regulators are out putting fine.

There is no DC on the bridging terminals.

I have clean audio on pins 1 and 7 of the op-amps. The capacitors on the input board dont seem to be leaking or smell funny.

The output fets are getting rail voltage but no audio signal.

I have clean audio on both sides of C202.

I have no audio on either side of C102.

Pin 1 of HB1 has +12 vdc

Pin 2 of HB1 has -12 vdc


One thing I thought I would mention:

HB101 pin 9: -3.104 vdc
HB101 pin10: -7.26 vdc
HB101 pin11: -10.85 vdc

These pins should all have 0.000 vdc

HB101 pin25: 0.000 vdc should have 3 vdc
HB101 pin28: 0.000 vdc should have 3.6 vdc

HB201 pin25: 0.300 vdc should have 3 vdc
HB201 pin28: -0.200 vdc should have 3.6 vdc

I dont know if this helps any but I am just wondering where I should look next?
 
Last edited:
seankane

seankane

Member
Joined 2010
No not yet should I do so?

Also not 100% sure on the orientation of the new boards as they are a different revision and dont look the same. Both new and old boards having writing on them wondering if I should install the new boards with the writing on the same side as the old boards. The ones I will be using are the same as I sent you. Any tips for that?
 
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Perry Babin

Member
Joined 2003
bcae1.com
On the driver board, pins 4 and 5 go directly to the base and emitter of a transistor. That should give you the reference you need.

Correction. That's pins 4 and 5.
 

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seankane

seankane

Member
Joined 2010
Perry Babin said:
On the driver board, pins 4 and 5 go directly to the base and emitter of a transistor. That should give you the reference you need.

Correction. That's pins 4 and 5.
Click to expand...

Ok I was just going to ask that, got it. Thanks Perry. From what I have described does it sound like a possiblr driver board issue? If so Why would both boards be affected? Could the power supply failure have something to do with it?
 
seankane

seankane

Member
Joined 2010
I replaced one driver board as you suggested and still nothing. No bias and no audio.

I removed the input board and removed the 10uf 16v caps and tested them all. One of them registered nothing, all the others were from 10.54 to 10.90 uf on my meter. I dont know what would be considered "out of tolerance on these" I am going to replace them all just because.

If no luck do you think the LM339 on PWM driver board could be faulty. The amp is drawing no current what so ever like its powered on but the channels are shut down if that makes sense.
 
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