Posts: 933
Threads: 140
Joined: Mar 2015
City: Lansdale
State, Province, Country: PA
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..
[Image:
https://live.staticflickr.com/65535/5083...fd89_c.jpg]
Schemati
[Image:
https://live.staticflickr.com/65535/5083...1798_c.jpg]
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
Posts: 7,214
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
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.[Image:
https://philcoradio.com/phorum/images/sm...on_eek.gif] The band goes to that white loop thingy (22 ohm resistor).[Image:
https://philcoradio.com/phorum/images/sm...wisted.gif] 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.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 837
Threads: 35
Joined: Feb 2015
City: Roseville, MN
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.
