[Hiwatt]

I recently picked up a Philco 41-296, beautiful unit, but needs a lot of love. I am self taught at this and the vast majority of restorations I have done are on British Guitar Amplifiers, so I am not quit up to speed. My question is about the filter capacitors, there are two a 128uf @ 400VDC and a dual can 8 uf & 16 uf @ 400VDC. Can these capacitors be replaced with modern electrolytic? If so will it matter if they are polarized or not. Second question concersn the res of the Philco labeled Capacitors inside. I was told it is a good idea to replace all of these, however, I have tested about half so far and all are with in tolerance on my meter. Is it necessary to replace these?

Thanks in advance for any help.

[Mondial]

I don't think there is a 128 uF, 400 V electrolytic in your radio. Looking at the schematic there is a 12 uf 400 V electrolytic at the output of the rectifier and a dual 8 and 16 uf at 400 V for additional filtering.

You can replace these caps with modern polarized electrolytics.

It is a good idea to replace the original tubular paper capacitors because even though they may test within tolerance, they are invariably leaky and will throw of the tube bias in some circuits. It is very important to replace the coupling capacitors in the audio section, especially the one between the first audio plate and the output tube grids.

These old caps also become unreliable and can open or short at any time, causing additional problems. If you are concerned about the under-chassis appearance, you can install new tubular mylar caps inside the original Philco cardboard shells.

Here is a link to the schematic:

http://www.nostalgiaair.org/Resources/417/M0013417.htm

http://www.nostalgiaair.org/Resources/416/M0013416.htm