Open Filament on scope

Marvin Moss

*Many thanks for all the replies from members.
*I checked the pins to make sure that they were soldered and even re-soldered them carefully.*
*I know it all depends on what kind of open there is and where it might be located.*
*I will have to let all know if I am successful or not.*
*My fondest thanks to all responders.  You folks are the best!!  A great group of helpers!!

Dave Peterson

Please let us know how it turns out. If successful it'd be good to know what ended up working.

New to the group, and new to Tek scope refurbishing. So full of newby enthusiasm. But have a history with these things and think this might be my retirement hobby! I've been looking for a good forum/group to interact with for sharing info. This seems like a good one.

Hoping I can find shared experiences like yours, so hope to learn what happened here. I've never heard of such a thing! Repairing an open filament with a cap discharge? Yikes!

Good luck!


I used to fix a rectifier tube in an old 30's radio I had in my tube
tester. It was a type I couldn't find locally so I put it in my old Simpson
tube tester and cranked the filament voltage up to 117. It was a 25 volt
filament and when you tapped the tube it would spot weld the filament back
together again. It would last a while and I would have to do it again.
With the CRT you're starting with nothing and if you totally blow the
filament you've lost nothing, so you can only win! Don't fear the