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Tolerance in resistors - Printable Version

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Tolerance in resistors - Guest - 08-10-2007

Hello friends.

I have a question. I am working whith a Philco model 60, and i need to know the tolerance in resistors used in those radios.
The resistors are in this page:
http://www.philcorepairbench.com/carbonres.htm

It is possible that the real value of those resistors are down to the nominal value? For example, if a resistor have a 51K of nominal value, now have 44K of real value. In all the radios that i see, the value in carbon resistors have more value than the nominal value.

Thanks for all.

- Texasrocker - 08-10-2007

Hello Jose. Im not sure if I fully understand your question, so hopefully someone else here will understand and explain better. However, I will try to help on resistors. Trying to read the old vintage resistors-values is a challenge at best for many of us! Your not alone friend!! I have found that having a schematic with parts values helps alot! Sometimes, the orig prints of schematics from the manufacturers will be abit different, from the JF Riders manuals as well, but close enough to work properly. I have found that resistors when "bad" read much higher in ohms if not already "open". Those need to be replaced. Tolerances on old vintage radios are "broad", usually + / - 10- 20%.Pay close attention to "wattage"- physical size also. Using the correct wattage is very important! If you stay within those limits, most vintage radios will be very forgiving. Hope I have helped, and I wish you best of luck on restoring your vintage Philco mod 60!! I have a completely restored Philco model 65 (lowboy cab) in my collection, and it is one of my favorites indeed!! Randal

- Guest - 08-11-2007

Hello Texasrocker.
Thanks to write to me. My english is not good.

I think this, taht the tolerance will be in those radios about 10-20%, but i need to know if it is 10 or 20%, to replace or not some resistors in the radio.

My case in this radio is not usual, because i have some resistor read low in ohms. I read in others vintage radios a high value of resistors, but this radio have some resistors tath are low from the nominal value.

Here you can see my radio: http://www.philcoradio.com/gallery/1933c.htm#r

Thanks
Jose Antonio

- Ron Ramirez - 08-11-2007

Hello Jose.

The tolerances of resistors in the old days was usually 20%. As you have mentioned, resistors usually drift UP in value but sometimes they can go DOWN as well.

- Guest - 08-11-2007

Hello Ron.

Thanks. I have some resistors whith 20%tolerance but others not. In this case, i will need to simulate those resistors.
I never make this, but put a new resistor is not beautiful in this radio.

Thanks Ron Icon_smile

Jose Antonio

- Texasrocker - 08-11-2007

Hello Jose. Your english is good!! If you have more questions I will try to help also if I can!! Best of luck on your restoration!!! Randal

- Guest - 08-12-2007

Hello Texasrocker.
Thanks for your words.
When i restore the radio, i will say to you.
You can see some in my blog, in the www button.