Use a HV microwave capacitor for HV CRT of RCA vacuum tube scope ?

[lordvader88]

I have an RCA-WO33A vacuum tube oscilloscope. Its was dropped hard and the transformer broke loose, cracking the PCB in half and bending the frame/etc. Probably broke 2 tubes as well. The replacement tubes and caps got here today. But I don't have a 0.5uF >700V capacitor. But I do have 2 or 3 big microwave oven caps. I have to dig them up. But if they are rated about 0.5uF is there any reason they might not work well at 60hz from a rectifying valve/tube ? Its for the CRT

http://rhetoricity.com/misc/tubes/oscope/RCA-Oscilliscope-WO33A.pdf

Its C40 on the mid-right

[Yansi]

They will work absolutely fine with 700V.

Just note there is usually a discharge resistor built in the cap, so you may see a false leakage current. It may or may not be a problem, depending on the circuit where you will use it.

[james_s]

Remember that a microwave capacitor is used with 60Hz powering a vacuum tube in its native application.