Oscilloscope fuse - timer - whatever - Help
 

Hello I have a National (Panasonic) VP-5512a (100) scope & the trace has stopped being produced, there appears to be a problem in the area of the PSU. I have not worked on this live as I am on Morphine for my cancer and I prefer to be alert when checking live. There is a component that looks like a thermometer and is marked 0 - 10 and it sits in a pair of fuse holders. It is open circuit at 0R and 20MR on the meter. Can you Identify the beast please and offer suggestions as to its repair/bypass. A source of a service manual would be useful. I appreciate any/all help, hints and tips, especially your time as mine is ticking away from me on a daily basis. Thank you.

Re: Oscilloscope fuse - timer - whatever - Help
 

That's an electrochemical hour meter, you pass a bit of current through it and the gap in the mercury moves by plating from one surface to the other. Looks like yours has gone past the 10,000 hours (marked on the PCB) and the gap is under one of the end caps, turn it round and it will creep back over the years. No need to bypass it the PSU will work (when fixed!) without it.

Here explains it... https://www.youtube.com/watch?v=Cxj399LuX1M

Re: Oscilloscope fuse - timer - whatever - Help
 

Thank you, I am grateful.

Re: Oscilloscope fuse - timer - whatever - Help
 

Thanks ever so much for posting this info.
I have 1-2 of those here somewhere and never could find out what they were. Now I know.