1.7 ohms on the secondary for the winding that supplies power for the floating supply, I think the winding is okay and there is no shorts to ground. I also checked the rectifier with the multi meter

CR712 is fine, hmm. No fuse appears to be blown, no voltage appears to be present, I hope the transformer is ok

I am certain there is a reason for every person that says no, rather than yes, to a higher priced 535. Just as I may say no to a higher priced antique car. My point is, that if you don't own it, you

It takes a village. The offer, of course, is also open to anyone else! -- With best regards Tam HANNA Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at

This is a good start, your help is appreciated!

Digikey shows several similar to the original. Surely something there will be workable? Not sure of the original PC Board drill pattern, however this series in particular catches my eye. DIGIKEY #

Checking CR712 in circuit seems to be reading abnormal using my diode test feature on the multimeter, it indicates this diode is conducting both ways with a dead short. Bare to mind I have removed all

F391 good

F391, I will find and check

I probed Q384 Q386 and found on the base of both transistors they are -1.2 volts, I see nothing on the collector or emitter of both transistors. Seems like the floating power supply maybe isn't

My hope was replacing the thermal pad would at least have me with something I can work with. I should point out the step generator was partially working when Q386 did not have a thermal insulator pad.

Recently I had Q386 that was shorted to the frame of the 577. I have replaced both thermal pads so now there should be no short. I reassembled this instrument and proceeded to test a transistor but

Tam and all the other generous members who came forward to help. Thank you so much! A member in Czechia has already helped me. Great to know that there are so many upstanding people here! Menahem

At least you know where an in town parts depot is! LOL Keitj

On the main board of the 577 R300 "Step Zero" appears burned and I would like to replace it. It is a 100k 30% 0.25W pot. Preferably I would like to replace it with the same type if possible. Also I

Chris if vibrations affect the offset I suspect a hairline crack in the core half. Any signs of dropping? Use a magnifying lens on the shiny mating surfaces of the core. Jon

Some tube scavengers are good for our hobby. They are the ones who are set up to market the rest of the parts of a scope back to us. With the aging of folks like Stan who acuumulated lots of

Yes, that is a good point, Chuck. I guess I am being a bit unfair and selfish. Unfortunately right now I'm in a situation where I have to be pretty frugal and it's frustrating but that's nobody else's

Perhaps we don't have the money? How much is a used 535 worth? Firstly as a scope. Secondly as a collector's object to be restored. Thirdly a source of oh so valuable tubes. Fourth as a source of

I've tried manually degaussing the probe with the wand I normally use for tape head degaussing, and it doesn't seem to have had any noticeable effect on the offset. One thing I do observe is that