[jzeferino]

Hello!

I'm working on a Philco model 48-808, and the 2-section dropping resistor needs to be replaced (green tube in the picture).

It's listed as R100 on the schematic, with section R100B (290 Ohms) currently open.

I would be great to find an exact replacement if anyone could direct me to a working part. If not, I don't mind replacing these two resistors by modern equivalents, but I'm not sure about the power they will have to dissipate.

Any help greatly appreciated.

Thank you.

Kind regards.
JZ

[klondike98]

Here is a link to the schematic.

[Radioroslyn]

Hi JZ and welcome,
Are your mains 220vac or 120vac?

[jzeferino]

220 VAC.

Thank you!

Kind regards.
JZ

[Radioroslyn]

Well the bad news is if you had 117v main you could do without it. The resistor is going to be dissipating about 15w I wouldn't use anything smaller than a 30w resistor.

[jzeferino]

Hi! Sorry for the late feedback.

I'm having a bit of trouble finding a suitable replacement. I'm looking at this Ohmite D25K300E, 300 ohms up to 25W or this Vishai FST05006E300R0JE, 300 ohms and 50W. The former is about half the length of the latter, although that one's power rating exceeds 30W.

Any comments are welcome.

Thank you very much.

All the best.
Joao

[jzeferino]

Hi.



I'm circuit tracing a 48-808 and one of the capacitors looks like a resistor.



It should be a 220uF cap as per the schematic.It's located on the audio circuit section in parallel with a 470k Ohm resistor (R203). It then connects to 50A5's pin 6 and to C200.


   



In the actual set, the electrical connections do match but for C201 there's a resistor-like cylinder with color code black, brown (orange?), red, red and silver.



   



Probably it is a capacitor format I've never seen as this section looks original. I've been checking capacitor color codes online but no luck.



Any help appreciated.



Thanks.

Joao

[jzeferino]

Sorry, C201 should be 220 MMF or picoF.

Thanks.

[Steve Davis]

That is a 220 mmf today we call it 220 pf 

Steve

[jzeferino]

but is that actually a capacitor? I've never seen one like that before.

Regarding its color code, is it read as red-red-brown-black? (from here: https://www.dcode.fr/capacitor-color-code )

Thanks.
Joao

[mikethedruid]

Yup, it's a condenser, same as the ones called "bumble bees" in the old Zenith sets, except theirs had a black background instead of brown. The silver band means it is 10% tolerance, and it is 220 mmf. I'd use a modern "lolly pop"  silver-mica type to replace it; they're 5% tolerance. See this link:  https://www.justradios.com/cart.html

[mikethedruid]

I looked at the schematic. I think you mean the part which is a tapped, 600 ohm wirewound resistor. I found this on eBay. Suggest you order it fast while it's still available. It will replace the one currently being used perfectly. You just don't use the extra tap.  https://www.ebay.com/itm/3-600-OHM-50-WA...7869!US!-1

[Radioroslyn]

How many cycles is your ac 50 or 60?

[klondike98]

I merged the two 48-808 threads to keep the questions for your set together. You can modify the title if you like to something like My 48-808 restoration.

[jzeferino]

Hi.

It's 50Hz.

Thanks.