I'm refurbishing a Heathkit IG-102 rf signal generator. It uses a number of RMC .02 μF +80-20 Z5U ceramic disc capacitors. Unfortunately a couple are missing from someone's previous mod. It has a green banded top.

Do you know what voltage this cap is?

If it is now unavailable is there a modern counterpart that I could use in its place?

Thanks for any help.

You can still get 0.2μF caps, but they are not common anymore. In the standard series numbering scheme used today, the nearest would be 0.22uF.

As for voltage, it depends on where it's used.

What part of the circuit are these caps used in?

A picture of the relevant part of the circuit has been sent for approval as an attachment to this post.

The location of the 2 caps of concern are on tag strip 'S', one between lugs 2 &3, the other between lugs 3 &4.

The power supply 'N' is 105-125 VAC.

Diagram uploaded to Post 3.

Wouldn't it be great to have such diagrams on everything we work on!

Some ceramic caps are used to compensate for temperature drift. Might be worthwhile checking if the green band means that these are temperature compensating caps, though it seems unlikely as they appear to be in the power supply circuit.

The schematic would be more helpful in this case.

The tolerance range for that cap is quite wide +80 to -20% (0.36μF to 0.16uF.) so the value can't be very critical to the circuit.

If it's across the mains then using a modern type X capacitor is recommended, such as this one:

https://www.jaycar.com.au/220nf-250vac-metallised-polypropylene-x5-capacitor/p/RG5238