AMS DMX / RMX PSU Upgrade Theory

[ecaltd]

Currently working on a DMX-15T project currently down to the motherboard and psu issues.

Question is... has anyone accomplished or entertained the idea of clearing out the stock internals and feeding the busses with new supplies ? The +5 has gone bad, the others were showing slightly off voltages and now it just blows the mains fuse, but not the rail fuses.

It seems to me that there would be plenty of room by removing the near to impossible to get toroidal and filter caps and installing COTS 5v switcher and "DIY" linears for the audio rails. Then removing the regulator IC's and associated circuitry and injecting voltages at the test points ???

Am I way off base here or is clean DC clean DC ?

Thoughts ?

Cheers,
gb

 

[radardoug]

I put a switchmode supply in one years ago, worked fine. The early ram used a 12 volt negative supply which is not necessary for later ram cards.

 

[ecaltd]

I put a switchmode supply in one years ago, worked fine. The early ram used a 12 volt negative supply which is not necessary for later ram cards.

Excellent, did you eliminate all the redundant circuitry ? Can you just remove the test point links and feed there ?

Thanks,
gb

 

[radardoug]

Its a while ago. I used a SMPS that produced +/- 15 volts, and 5 volts.

 

[ecaltd]

Its a while ago. I used a SMPS that produced +/- 15 volts, and 5 volts.

Perfect, will start pulling regulator chips tomorrow.

Might anyone know the pinouts for the edge card busses to verify ?

 

[mrclunk]

Replacement RAM boards and handy extenders if needed.

http://www.soundlock.co.uk/product-category/for-third-parties/

 

[ecaltd]

Replacement RAM boards and handy extenders if needed.

http://www.soundlock.co.uk/product-category/for-third-parties/

These are absolutely brilliant !

 

[Whoops]

Question is... has anyone accomplished or entertained the idea of clearing out the stock internals and feeding the busses with new supplies ?

I haven't done it with that unit but done it with others.
I did that on a SPX90, completely removed the original PSU that was beyond repair and installed a new one

 

[ecaltd]

And now we have a clean slate with plenty of working room !

 

[Whoops]

What voltage rails do you need?

 

[ecaltd]

What voltage rails do you need?

Ideally, the voltages on the card edge connectors. I would like to verify continuity on all connectors before I start puting cards in again.

Thanks !
gb

 

[Whoops]

Ideally, the voltages on the card edge connectors.

Which are?

 

[ecaltd]

Which are?

The blue connectors on the motherboard.

 

[ecaltd]

Cleaned up, found those pesky tantalums,put led indicators on the rails...out of all the bizarre and random components in the shop I didn't have a single 7812 or 7905

 

[ecaltd]

Switchers and DC fan installed...

 

[ecaltd]

Cards back in with no explosions ! Next new ribbon cables and see if it passes audio

 

[ecaltd]

IT'S ALIVE ! ... I think...

 

[radardoug]

That display looks a bit strange. Maybe its a very early unit, with different software? I would like to see a picture taken straight on to the display.

 

[ecaltd]

Any better?

 

[radardoug]

Ah, its not an RMX! Display looks good, how does it sound?