GA4566-1 servo drive REPAIR or REPLACE

[cogoman]

We have a FADAL 4020 with a bad servo drive card (older GA4566-1 short card). We sent it to a repair facility that claimed to repair these boards, but when they found out that some of the output transistors (GTK45595) were dead, they said they couldn't repair it. I have seen some other repair places on the web that claim to be able to repair these:
A: acsindustrial.com
B: nyco-systems.com
C: plccenter.com
D: servo-repair.com
E: perhaps kmac-parts.com
F: perhaps teknic.com
Can they only repair these if ALL the transistors still work?
Also fadalcnc.com has a "DC-UNIVERSAL AFTERMARKET" amp card "AMP-001A" for which they don't provide much in the way of technical specs, but it might work. Also ajaxcnc.com has what looks like a good DC servo drive, though the current might be a little lite, and it would need the feedback system changed to their own encoder.

What do you think would be the best way to get the 4020 back up and reliably making parts?


As an aside, it appears GlenTek has made a great effort to keep these transistors parameters a secret There must be somebody who knows servo boards well enough to suggest a good replacement for these devices. ON semiconductor makes some pretty beefy TO-3s. I suspect there may need to be some modifications to keep more modern fast transistors from oscilating in the older boards.

Thanks for any help you can provide. Trying to get an older servo drive card repaired or replaced seems to be peppered with pitfalls for those who don't know better.

PS: I suspect it's got a -0 controller; 1040-0, 1020-0, 1030-0, and 4 by 1010-1 plus a 1420-1 and one other card with lots of memory chips where the other cards have part numbers.