[bmklawt]

I have a Gentek servo amp made for Anilam in the early 1980's model GA4561, there are four transistors on this and I know at least one of them is bad. Transistor is a GTK45583, replacement transistor is GTK45578 at $90.00 each, anyone know of a suitable replacement for this transistor.
In my google search I have found these transistors and possible replacements, MJ10020, MJ10015 or MJ11032.
This amp is running a SEM MT30 servo motor, 75 vdc.

Any help I could get will be greatly appreciated,
Bruce

[unterhaus]

it's likely that this is being run in PWM, if so then a lot of transistors would probably work, possibly with some changes in resistors.

[Al_The_Man]

If you can find the data sheet on the GTK's and find out if they are power darlingtons, as the MJ11032 are, and are a replacement for the type used in the Westamp similar amp.
But I think I have read somewhere the GTK's are different technology? IGBT's ?
Al.

[unterhaus]

looks like that is actually a glentek part number, so you want a replacement that isn't.

[bmklawt]

They want $90.00 each for the Glentek transistor so yes I am looking for a non Glentek replacement.
Looking at the 3 amps I have, each has 4 GTK45583 transistor, I just noticed one transistor of the 12 total is a Motorola 2N3773, see first transistor in first photo. I'm going to to replace the one known bad one with a 2N3773 and see how it goes.

[Iron-Man]

They want $90.00 each for the Glentek transistor so yes I am looking for a non Glentek replacement.
Looking at the 3 amps I have, each has 4 GTK45583 transistor, I just noticed one transistor of the 12 total is a Motorola 2N3773, see first transistor in first photo. I'm going to to replace the one known bad one with a 2N3773 and see how it goes.

Data sheet for 2N3773; http://www.onsemi.com/pub_link/Collateral/2N3773-D.PDF

Good Luck,

Iron-Man

[bmklawt]

I replaced the 4 GTK45583 transistors with 2N3773 and the amp is now working.
I bought the transistor from www.digikey.com/scripts/dksearch/dksus.dll?vendor=0&keywords=2n3773+ about $4.00 each