The PHILCO Phorum
Philco 81 Questions - Printable Version

+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Philco 81 Questions (/showthread.php?tid=16305)

Pages: 1 2 3

RE: Philco 81 Questions - ohiobill - 02-27-2017

Thanks Terry, I'm making a list. Not doing any work on my radio till I have the right safe equipment to use. Been reading a lot on how to check out this old radio. Just not the right equipment yet. Thanks again

RE: Philco 81 Questions - ohiobill - 02-28-2017

Looking over my schematics for this model 81 I notice there are 2 compensating condensers , do i need to replace them. Also there is a wire wound resistor that looks to be only 325 ohms. Do i replace it with a normal resistor. Still learning a lot from you guys. Not jumping into this thing yet. Just looking

RE: Philco 81 Questions - Mondial - 02-28-2017

Do not replace the compensating condensers. These are trimmers used in alignment and should not need replacement. That also goes for the mica caps, as they don't usually go bad.

The wirewound resistor should be left alone if it measures close to the indicated resistance value.

RE: Philco 81 Questions - Radioroslyn - 02-28-2017

Generally compensating caps and mica caps are hold up well over time and don't typically require replacement unless physically damaged. The 325 ohm resistor is a wire wound and hold up well too. You can check it w/your ohm meter to confirm it's resistance.

RE: Philco 81 Questions - ohiobill - 03-01-2017

Thanks, I have read where the mica caps don't have be replaced. Good to know I don't have to replace the comps. I ordered a new cord and fuse holder to mount in the chassis. Will start digging in to the chassis soon. I think some one has done this chassis before. There are no paper caps in it.

RE: Philco 81 Questions - klondike98 - 03-02-2017

The paper caps are inside the bakelite blocks that have the solder lugs on them. Easy to restuff. See tech section for a tutorial thread and info about them.

RE: Philco 81 Questions - ohiobill - 03-05-2017

I think the first purchase will be a variac. Will a 300 or do I need a 500VAC do the test on these old radio"s with transformers. There are some on ebay. I did see some signal generators on there too. Don't know what brand would be better. Do I need a oscilloscope too. Or just a dial generator to home into a frequency. Still reading on testing circuits

RE: Philco 81 Questions - Radioroslyn - 03-05-2017

>I think the first purchase will be a variac. Will a 300 or do I need a 500VAC do the test on these old radio"s with transformers.

I think you mean 300 watt or 500watt unit which = about 3amp or 5amp. Either is plenty big. Most radio reciever is going to be 30 to maybe 200 watts tops. That would be a large 15+ tube set.

<I did see some signal generators on there too. >

For just doing broadcast sets you don't need a particularly high end unit. There are a lot of 1950's-60's kit built ones like Heathkit and Eico. General your looking at abt $25 or less. A handy gizzmo to get is a frequency counter. What this will tell you is the exact frequency of an oscillator, like your signal generator or local oscillator in your receiver. With one of these you don't need to rely on the accuracy of the generator's dial. It can be had for abt $10 from China.

> Do I need a oscilloscope too.

I wouldn't bother with one if you are just servicing receivers. If you were doing TV's it comes in handy. There's a bit of a learning curve to get use to one too.

RE: Philco 81 Questions - ohiobill - 03-06-2017

Thanks Terry,You are very helpfull. I did get my cloth line cord and fuse holder . I think I am going to put a polarized plug on the end , just a two wire plug and follow the one at the common side which is the larger terminal and hook the other end to the capacitor block where the old wire is now. The hot side I will put the fuse inline and solder that side to the on off volume switch where the original wire is.  I did my capacitor block gutting . Was real easy using the heat gun for a few seconds. Now to buy the new capacitors.

model 81 capacitors - ohiobill - 03-07-2017

I have my schematic and picture diagram Page  8  of 27 showing block capacitor as #35 in the picture. On page 8-28 of the parts replacement page it list #35 as having two capacitors. That is right . But this part show that they are two .015
capacitors. The ones I pulled out of my radio are marked with a large 8 on them. What do I replace them with.

RE: model 81 capacitors - Radioroslyn - 03-07-2017

Just go with the values listed on the schematic/parts list. Don't know if there is a reference to the numbers 8 or 10 as printed on the original caps.

RE: model 81 capacitors - morzh - 03-07-2017

Don't pay attention to marking. If it says 0.015uF - this is what you need.

RE: model 81 capacitors - ohiobill - 03-07-2017

The block where the no 10 came out of , the parts list shows a .09 capacitor.  I guess the 10 being next value higher would have been ok. But I will stick with a .09.

RE: model 81 capacitors - Kenneth F. Besso Jr. - 03-07-2017

Stay TRUE to the schematic----and-----to all the changes that RON has posted for this Great little Model,,,have fun,,,CHEERS

RE: model 81 capacitors - Radioroslyn - 03-07-2017

(03-07-2017, 07:11 PM)ohiobill Wrote:  The block where the no 10 came out of , the parts list shows a .09 capacitor.  I guess the 10 being next value higher would have been ok. But I will stick with a .09.

.1mfd remember.