tek 2235 scope p/s problem

"pindiode" wrote in news: snipped-for-privacy@localhost.talkaboutelectronicequipmen t.com:

If it is the SCR,it's in an overvoltage crowbar circuit,with a 51 V zener,shorts a 3 ohm resistor to ground to put the PWM IC into 'burst' mode. Tek p/n 151-0506-00,mfg.# C106B2X283(mfg=General Electric). It's all part of a pre-regulator that knocks rectified line V down to ~43 Vdc for the power oscillator.

Sorry,I don't have any 2235 schematics. The PS is similar to my 2213 PS. The 51 V zener can also be out of spec and causing the SCR to trigger prematurely.

The service manual lists Q908 as a PNP TO-92 transistor, mfg p/n 2N2907A, TI p/n 151-0164-00.

Doug,

I just checked Bama (bama.sbc.edu) an FTP web site. They have a 2225 Manual for download. Maybe that will help.

Good luck with that scope!

Regards, Jim

hello everyone thanks for the help i read some of the old posts on this scope and should be able to get it going now,thanks again

doug/aar3ir

..snip..

The circuit of the 2225 Scope is completely different to the 2235/2215 scopes.

And, as far as I can check this on bama, the 2225 manual is operating only, not the service manual (so there are no schmeatics).

hth, Andreas

snipped-for-privacy@bigfoot.com (TekMan) wrote in news: snipped-for-privacy@posting.google.com:

Yes,a 2213 or 2215 (or 'A' version) manual would be more applicable to working on a 2235 PS.

An 'A' version manual would be most similar.