Hi, I replaced a resistor in conjunction with a selenium to silicon diode. Increased
resistance well above the 100 ohm benchmark increase.
The modern resistor was smaller physically than the original 1946 component. Normal.

Didn't figure wattages. Went with the acid test. Radio plays fine. After about 3 hours
I flipped the chassis over to check resistor for heat. Easily touchable, but turned from
tan to brown with the center black!

Is this normal? I repeat, resistor not hot. Radio plays fine.

let it go.

Terry

What was the wattage rating of the replacement resistor? Using a higher value resistor will drop more voltage and get hotter. Probably need a 1 or 2 watt resistor. I don't like to see a resistor getting hot to a point of changing color. If it wasn't hot what caused the color change?

Maybe it got hot due to current surge during power-up. Best to verify wattage needs and leave room for comfort.. not to mention safety.

Norm my friend, that is the pregnant question. I only tried it briefly between recap
sessions. At one point It wouldn't work. All looked normal, so I did the final five caps,
as I didn't know what else to do. It came up quite nicely.

I think it's a 2 watt resistor, but the thing is, it's not hot, and the radio plays well.
Perhaps there was an event I didn't notice that caused a temporary overload of
the resistor. I could replace it with an identical, and see if it darkens too.

I seem to recall another thread with new darkened resistor syndrome. Don't know
if some modern resistors do that normally.

Thanks for the replies guys.

But other than charging the filter caps, very little current is drawn till the tubes start conducting...

If it changed color it got hot, period, when I dunno... If it's not hot now it'll probably be OK but I'm leery of a hidden issue...

Tom

I'm good at that Tech. If it fails It'll be Baaakk! Actually, It's still my radio.

Good point, Tom. The surge should be very brief to charge caps. Sounds like either a (presumed) current draw issue went away or perhaps it's simply gone into hiding.

You Guys were All right.
I said it was easily touchable. Actually it was, by the time I got the chassis turned over.
I ran the radio upside down, and touched the resistor...GAAH!
Sorry to have mislead you. I'll try to improve my question quality in the future.

Still, there may have been a high current draw event, as I'm tracking an intermittent
gremlin now.
BTW. I beefed up the resistor wattage.

Thanks Guys, terry h

One thing that occurred to me was a possibility that the resistor saw a greater-than-rated voltage drop prior to charging the caps. We must bear worst case in mind when using today's components. Most modern-day folks don't work in what is now considered the too-darned-many-and-then-some voltage range.

Follow the volts. Fault lies after burned resistor in voltage divider. Just think about it as a ladder from all to none.

Basic calculation (mostly ignored here) is to rate the part according to ohms laws and allow a substantial leeway to air on the safe side.