7934 free for the taking, Two of them.


Karin Johnson
 

THIS IS GOING TO BE LONG SO GRAB A CUP OF COFFEE.
Well it finally happened. My beloved 7934 just stopped working today. Actually I've got two of them, and the other one is flaky too.
SOOOOOOOO... The symptom has nothing to do with the dreaded "tick". The inverter will not start at all. Checked fuses, all OK.
The line voltage feeding the diode bridge which feeds the two "line capacitors" producing the inverter input DC all OK. But the inverter
will just not start. I wanted to swap the power supply module with the other 7934, because that one worked. I say "worked" because I will explain
later. Swapping power supply modules is not easy, as the input line AC is hardwired into the chassis. So here is where is gets really insane.
I completely tore apart the first 7934. It is pieces all of the boards are out, the chassis is in several parts. I did take some pictures with the intent
of putting it back together. But after fiddling with it all afternoon, I am totally disgusted. I don't think the 7934 I tore apart will ever go back together again.
The other 7934 that sort of works, is a unit that had a failed HV transformer. This unit has a rewound HV transformer in it that I did several years ago.
I just put this unit in the closet, as sort of a spare. But today when I powered it up the focus would not clear up the read out numbers the trace focused OK
but the read out was wonky. Also with my 7L12 plugin selected the trace had a lot of distortion on it. Don't know what else to call it. After being powered
on for a few minutes I detected a burning smell. Initially I thought it was from my rewound transformer, but after taking the power supply out of this unit
actually just sliding it out the back I could smell the same burning odor from the power supply unit.
So now I've got two wonky 7934.
I really don't have the energy and patience at this point to continue the troubleshooting effort. I consider these two 7934 parts unit at this point.
One of them definitely a parts unit. The other may be able to be resurrected, I honestly don't know.

So here's the offer.
First come first served, Two FREE 7934 one in pieces the other in one piece sort of functional.
I really would like local pickup if at all possible, but if need be I can ship, but would like some sort of sharing of cost on shipping.
I actually have also a real Tektronix HV transformer that I purchase some years ago. It appears to be NOS. I'll even throw in couple of plug
ins if you desire.

Karin Anne Johnson
Palm Harbor, FL


Karin Johnson
 

I've had several replies regarding the two 7934s. Here is what I'm going to do. Yesterday when all of this happened was a total disaster. I realize that now.
Oh well, life goes on. What I am going to try is to put the disassembled 7934 back together, if my patience holds out. I am not going to work on this task
much more than a couple of weeks. So guys HOLD ON. These things may be coming your way.
Like one of the folks who replied, I tend not to give up on things. Right now I'm a bit calmer, and will try to get the power supply with the faulty inverter
working. I'm not going to spend forever on these things.
So I beg to have your cooperation at this point. If I ship these units I am inclined to just cover the costs myself right now.
Karin