View Full Version : Old Resistor Values in a Sentinel 344


Seafarer12
05-31-2009, 08:58 PM
I have an old sentinel 344 radio I am working on. I have been unable to find a copy of the schematic so I am having to work by the color code to replace a bad resistor. The color code isn't making sense to the standard color code. They are large about the size of a pistol shell casing. They have a five band color code. The resistor I need to replace has yellow-pink-orange-black-yellow. The resistor was broken so I can't measure it. I measured another one to check it has yellow-violet-orange-black-yellow and measures about 1 Meg. I measuerd the small resistors and they check out with their color code. Is there a different color code out there?

jeyurkon
05-31-2009, 09:02 PM
Sounds more like a capacitor. Is the first band double wide?

John

Seafarer12
05-31-2009, 09:33 PM
all the bands are the same width and there is a space between one band and the other 4 like a resistor, there are 4 of them in the radio. They are a hard plastic. If it is a cap I have never seen one like it. I replaced the elec and wax cap in the radio already. I guess it would make sense since there was only one wax cap, one dual elec, and one 6 dot mica.

I was looking at the color code for caps and assuming the pink band is violet. They translate to .047 uF . Which makes a lot more sense.

jeyurkon
05-31-2009, 09:59 PM
Could you post a photo? The first band isn't usually part of the value.

http://www.radiodaze.com/catalog-306-colorcode.pdf

John

Tom Bavis
06-01-2009, 07:59 AM
Schematic is in Sams folder 211-12, 1953. This about the right vintage for the Sprague "bumblebee" capacitors. As you have measured, they've all turned into resistors by now.

Seafarer12
06-01-2009, 02:25 PM
http://i200.photobucket.com/albums/aa47/seafarer1976/2009-06-01001.jpg

Here is a picture. Tom do you have that particular sams folder handy. Do I have the value right? Thanks,

I assume the big one is a .047 and the small one is a .01 from the color code I found here
http://www.tpub.com/neets/book2/3g.htm

truetone36
06-01-2009, 05:09 PM
Hmmmm.....those look like bumblebee caps to me.

PunkTiger
06-01-2009, 06:08 PM
*heh* Wow! An Aerovox component! My parents worked for Aerovox back in the 1950s.

Seafarer12
06-01-2009, 06:12 PM
http://www.pickguardian.com/pickguardian/Images/Sprague%20Bumblebee%20Chart.pdf

I found a color code chart for bumblebee caps. You learn something new everyday.
Thanks for the help guys.

jeyurkon
06-01-2009, 10:12 PM
http://www.pickguardian.com/pickguardian/Images/Sprague%20Bumblebee%20Chart.pdf

I found a color code chart for bumblebee caps. You learn something new everyday.
Thanks for the help guys.

It looks like you have the values right. The bumblebees have a different code than the tubular ceramics, which I thought you had at first.

The guitar amplifier crowd really like the bumblebees. I don't think I could hear the difference.

John