Resistor question - Printable Version
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Resistor question - DKinYORKpa - 01-13-2013
My Philco 18 has a resistor that the schematic and the parts list says is 32K. Out of the circuit, it measures almost dead-on 20K. It's #61. Is this possible? If possible, would a 2 watt replacement be OK?
RE: Resistor question - BrendaAnnD - 01-13-2013
What are the body-end-dot colors of the original resistor? 32K would be body= orange end= red and dot= orange. If not, it may be a replacement or modification.
RE: Resistor question - DKinYORKpa - 01-13-2013
Quote:What are the body-end-dot colors of the original resistor?
Body is orange, end is red and no dot. But that would normally mean the dot is the same color as the body, right? I had two 20K resistors that read 15K and 14K. Their markings were correct. I not used to seeing them go down in value.
RE: Resistor question - BrendaAnnD - 01-13-2013
It is rare that they will go down in value. I've only seen a couple that way. Replace it with a modern 33K (I prefer flameproof). I think the largest resistors in these radios that are not wirewound are 3W, and those are the very large dogbones. Most are half watt. 2W replacement may be overkill, but will work.
RE: Resistor question - DKinYORKpa - 01-13-2013
After looking at Chuck's site about Philco resistors, I'm sure it's a 2 watt. The drop in value seems odd, but all signs point to it.
RE: Resistor question - Arran - 01-13-2013
When and if you can find a parts list most of the B.E.D code carbon resistors used in Philcos were between 1/4 Watt to 3 Watt, depending on the circuit. Contrary to popular belief resistors with a maximum power dissipation of 1/2 Watt was not the floor in terms of those used in old radios, many used 1/4 Watt and even 1/3 Watt resistors if they thought they could get away with it.
If you can find a parts list for a given set that will tell the story, as with now it was all about cost and pinching pennies, if a 1/4 Watt resistor cost them 1 cent less then using a 1/2 Watt then they would use the 1/4 Watt. If you can use six 1/4 Watt resistors in a radio that's 6 cents saved per radio, when you are producing 100,000 or even 1,000,000 radios that's $6000 and $60,000 trimmed off the manufacturing costs. Thanks to some short sighted thinking as to where to use a 1/4 Watt resistor, every Canadian G.E and RCA model made between 1940 and 1946 ends up needing the plate resistor replaced on the 6SQ7 first audio/second detector tube.
Regards
Arran