Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Parts list or Volume Pot Value
#1

Does anyone have a Parts list or the Volume Pot Value for a 41-280 (121)?

Jerry Gatewood
Philco 41-280 (121)
#2

looks like 2meg taped at 1meg.
Terry

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#3

here's a link to the schematic from Nostalgia Air.
http://www.nostalgiaair.org/Resources/414/M0013414.htm
Terry is correct.

Happily back in Illinois..not.
#4

If push comes to shove you could use just a 1 or 2meg pot without the tap. The tap is to add low frequency response at low volume (loudness control).
Terry

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#5

Jerry,
In your other thread on this radio (maybe Ron could put the two together) you stated the radio was working before it was recaped. So here are a couple of things I am thinking about. If the volume control reads less than one ohm (I think you said .450 ohm), the radio would never have worked. The other thing is, I don't think the pot could ever change in value that dramatically. You might want to retest it. The pot has three terminals located together and the tap terminal is located at some other point. You want to take your measurement from the two outer terminals of the group of three. Let us know what you find.
Steve

M R Radios   C M Tubes
#6

Sorry for the long delay, Just got back to a point to work on it again. I measured the 2 Outside terminals and all the way up, it measures approx. 150 Ohms. All the way down it measures approx 1 Meg. Ohms. About 9/10ths turned all the way up it jumps to the Kilo Ohms range (approx. 49.2Kilo Ohms) before jumping immediately to the 150 Ohms reading. This is consistent and can be duplicated every time.

Jerry Gatewood
Philco 41-280 (121)
#7

As Terry and Glenn have stated previously, the original volume control potentiometer is 2 megohms, with a tap at 1 megohm.

You may not achieve a reliable measurement of the potentiometer unless you disconnect it from the circuit.

I strongly suggest you invest in a can of Caig DeoxIT D5 to clean your volume and tone controls. Expensive, but worth it. It will clean controls and switches when other contact cleaners fail. And it does not take a lot, nor do you want to spray a lot in each control since the stuff is expensive. Use it sparingly. Follow that up with a spray of Caig FaderLube F5 (for potentiometers and controls only, not switches).

I've found it is mandatory to clean controls and (especially) pushbutton assemblies of 1939 and later Philcos with DeoxIT in order to achieve proper operation. As an example, I have a 41-226 "Sled" with six pushbuttons. They would not work consistently, even after spraying with a contact cleaner. Just a small spray of DeoxIT on each contact restored the assembly to proper operation, and all six buttons work perfectly now.

Now, after all that...if cleaning the potentiometer does not solve its issues, then look at replacement. But try the DeoxIT first.

Oh, and I'll leave this as a separate topic, since we are discussing a specific, important item (volume control). Icon_smile

--
Ron Ramirez
Ferdinand IN
#8

Hey guys just for grins take the 2 .01 caps that where hooked to the volume control and connect the loose ends together. If your set is working properly it will play at full volume.
Terry

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#9

I do not have 2 1k Caps. I enclosed a pic of the pot.

Jerry Gatewood
Philco 41-280 (121)
#10

ps Your pot isn't wired properly as per the diagram. The terminal to the right should be connected to the chassis. the next one should have a .01 going back to pin 3 of the 7C6. The terminal to the left should be connected to .01 cap that goes to the junction of two 470k resistors and a 100uufd cap. Double check your wiring and report back.
Terry
pss Looks like you've got a short where the .01 is connected to the terminal strip.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#11

I was thinking something didn't look right but Value wise only, But the Radio worked before I re-capped it and I replace each cap 1-1.

Jerry Gatewood
Philco 41-280 (121)
#12

And here is a Pic of the Original Layout......

Jerry Gatewood
Philco 41-280 (121)
#13

I am also buying an Oscilloscope today to help testing. Theoretically I should be able to connect to the left pin on the volume pot and get deflection....correct?

Jerry Gatewood
Philco 41-280 (121)
#14

Do you know how to count the pins on loctal tubes?
Terry

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#15

I have a schematic, haven't yet but could probably figure it out pretty quick. Icon_thumbup

Jerry Gatewood
Philco 41-280 (121)




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
1949 Motorola 5A9M
LOL!! Well Arran, if you do dive into it and come across any advice on dealing with accessing components let me know. I...klondike98 — 11:56 PM
1949 Motorola 5A9M
Bob and Gary; I have the further complication on the Phillips that they decided to use some 200 volt rated paper caps...Arran — 10:05 PM
1949 Motorola 5A9M
Thx Arran & Gary. Yes its super crowded in the chassis and I've debated whether to try to restuff caps or not. I t...klondike98 — 07:40 PM
1949 Motorola 5A9M
That's got to be one of the tightest conglomeration of components I've ever seen! I wonder how the line workers felt bu...GarySP — 05:46 PM
1949 Motorola 5A9M
Bob; I think that the Phillips was actually manufactured in Canada, though they may have imported many of the compone...Arran — 02:28 PM
1949 Motorola 5A9M
I've started replacing the electrolytic caps now. As Arran mentioned, they are housed under a metal strap. Here's a ph...klondike98 — 12:22 PM
1949 Motorola 5A9M
Thank for that info Arran! Very interesting. Phillips and Motorola must have made some type of marketing deal back then....klondike98 — 11:49 AM
46-1213 Schematic Question
Good idea on the fuse. These old transformers need extra protection.RodB — 10:02 AM
46-1213 Schematic Question
Hello Larry, Well, anyway I can contest about noisey grounds in my living room when I am using one outlet in my house a...radiorich — 08:03 AM
46-1213 Schematic Question
RodB & MrFixr55, Thank you both for the great replies at my questions, I appreciate the help very much.  As suggest...MissouriLarry — 07:04 AM

[-]
Who's Online
There are currently 1504 online users. [Complete List]
» 1 Member(s) | 1503 Guest(s)
Avatar

>