Tektronix TAS 455 Faulty high Voltage module?

[sebbonit]

Hello guys.

Maybe you have some ideas where can i find a schematic for Tek TAS 455 with that module? So fary every one i've seen doesn't have that module there or I'm reading it wrong.
I received it in working order but while I was testing it around (It was working for around 14minutes) a Mosfet IRF640 on a high voltage module broke.
New fets are also getting very hot and die.

Does anyone have any idea what might be the problem?

Thank you for all your help!

[m k]

Tek Wiki has something.
Preregulator seems to be the usual, so bypassing it and feeding a current limited 43V directly in can give some ideas.

[sebbonit]

It seems like B020 serial number units if I look at the schematic have completely different power supply unit. I cant even locate where the 43volt should be in mine 
Also the voltages should be correct because everything is working as it should when i change the mosfet for a new one, i have the display working and so on but it is just getting hot and dies after some time.

Mosfet gets around 15V between drain and source and the gate 11.1 at around 52.6kHz

[m k]

Dang, and I thought this TL594 style is ancient.

Seems that older schematics are hiding.
Maybe some other model has it also.

[sebbonit]

Will search the whole wiki soon.
Anyway thanks for trying to help! 

[m k]

Maybe some 2000 series models are its forefathers but keep in mind that their numbering has nothing to do with their age.