Leslie 50C 6550 grid/cathode voltage check

Testing both grid and cathode voltages simultaneously to find a case of tube overheating.

Category:

Science & Technology

Tags:

• Leslie
• 50C
• 6550
• grid
• cathode
• voltage
• check

[gadget73]

Sounds like a gassy tube. I ran into this with a 6GK6 in an amp doing exactly the same thing. Tube tester rang it out OK. I did some more checking, and it was fine under 200v on the plate. It just wouldn't work in the circuit at 300 volts though.

[retrochad]

@gadget73 That's a good idea..I still think it may be in the socket though as even when I switched the tubes, the rear socket still exhibited the problem.

[chickenofsea]

Did you get the problem solved?

[retrochad]

@chickenofsea No, not yet, I need to find a new socket...we still may have some ceramic sockets left over from the last amp with bad sockets but if not will need to order some.

[umajunkcollector]

Chad, sometimes you amaze me with some of the most far reaching simple possibilities, and often times you hit the nail on the head - whereas many technicians would be playing guessing games with things like this. Of course I assume that you checked the tube first. Do you have an electronics engineering degree? I've known some ham ops that also are engineers that talk alot, but who really are fools when it comes to a real understanding.

[retrochad]

@umajunkcollector Thank you...I did test both tubes, both test good, also switched the tubes and the problem stayed with the socket toward the rear. Also new capacitors going to the grids. I have seen several cases of electrical leakage in tube sockets; just experience with odd problems can help a lot. I do have a BS degree in communications (broadcasting), but no formal engineering schooling, I just have a lot of experience.

[TheMultiGunMan]

★★★★★

[americantrucker85]

you got me interested in learning how to working on old radios and stuff like that

[kiyotewolf]

that's really cool you know tube electronics. I wish I did.

[MrHeyyou34]

Great troubleshooting Chad. It is amazing that sometimes the simple stuff, gives us a lot of trouble. If someone has never run into this bad socket problem, they might chase their tail around & around the circuit to no avail, they might not suspect the socket. I'll remember this if I run into any problem like this. Thanks so much for the videos.

[gadget73]

@retrochad ah, yeah if it stays with the socket, its probably not the tube. My issue stayed with the tube.

[koioo2]

satement is okay.can t help you