The PHILCO Phorum

ALL, this has a old type rectifier.. I want to replace it.. I will use a 1N5408 ..what value of resistor do i need with it..



Schemati



2nd Question is What can In use for the 2 caps on the AC line? they are .004 uf

i have a y2 cap -0047 and a x2 cap .0047 can i use either of these?

thanks
Skip

To answer your questions sir, I would take a guess at abt 100 ohms or less. You may be able to install the diode and not have to add a series resistor. Just check your B+ to see if it's @ 120vdc under load. Note the diagram has the diode drawn backwards. The band goes to that white loop thingy (22 ohm resistor).  The trick is that the filter caps are going to charge up before the the tubes get hot to provide a load for the B+. This means that for a few seconds after the set is turned on the filters may be seeing 160-170vdc till the tube warm.

The .0047 are fine to replace the line bypass caps.

Hi Skip, If the set has FM, which it appears this does, then the B+ should be as close to what is on the schematic as possible. So, you can try different values starting with 47 ohms, 1 watt. I usually use a variac to bring it up slowly. If I hit B+ before getting to line voltage then I need a higher value. You can use the X2 caps on the line. Y2s are for transformer primaries.