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Philco 144B low volume - Printable Version

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Philco 144B low volume - Tucker - 06-07-2023

Hi,  I just replaced the old speaker wires that were falling apart on this radio and now I have low volume. That’s the only repair I’ve made as this radio was already recapped and playing good.  
This radio uses 3 wires from the chassis to the speaker as the output transformer is on the speaker. 
I mapped out the original wires on paper but they were so faded I couldn’t be sure of the colors.
Is there a simple way of sorting the wires and determining which wire goes where without pulling the chassis?

RE: Philco 144B low volume - DaleHCook - 06-07-2023

I have only begun indexing the service info on PhilcoRadio.com, but the 144B is probably very similar to the 144. Is the speaker plug a D-shaped plug made of three layers of phenolic? If so, then after you reply I will know how instruct you to proceed.

RE: Philco 144B low volume - Tucker - 06-07-2023

The speaker plug is a D shaped plug made of 3 layers of phenolic material. It actually has 4 pins but it only uses 3 of the pins.

RE: Philco 144B low volume - Radioroslyn - 06-07-2023

I'm not sure if the 144B had the 4 pin spkr plug on the back of the chassis. Some of the larger sets didn't like the early 16B's. They were wired straight into the chassis with no plug. Bit of a hassle to service and it's not noted on the diagram.

It's much easier to sort w/the chassis out of the cabinet. The top of the winding on the output transformer goes to pin 2 of the 42 tube. The bottom winding of the output transformer goes to pin 3 of the 42 tube and is connected to field coil at the transformer. The 3rd connection goes to pin 1 or 4 (doesn't matter) of the 80 tube. It's connected to the field coil.

If it does have a plug then it's a bit of work carefully remove the 2 brass rivets and then use an ohm meter to check that the connection are wired properly. I found some black pop rivets that work well. I'm too lazy to use the brass ones and a punch.

https://philcoradio.com/library/download/service%20info/service%20bulletins/Philco%20Service%20Bulletin%20193.pdf

You'll have it working in no time!

RE: Philco 144B low volume - DaleHCook - 06-07-2023

Radioroslyn Wrote:I'm not sure if the 144B had the 4 pin spkr plug on the back of the chassis. Some of the larger sets didn't like the early 16B's. They were wired straight into the chassis with no plug. Bit of a hassle to service and it's not noted on the diagram.

If the 144B is largely the same as the 144 I would expect a speaker plug because the 144 print has Xs imposed on the three leads going to the OT primary and the field coil (a convention sometimes used to designate a speaker plug and socket), and the parts list specifies a speaker socket.

RE: Philco 144B low volume - DaleHCook - 06-07-2023

Tucker Wrote:The speaker plug is a D shaped plug made of 3 layers of phenolic material. It actually has 4 pins but it only uses 3 of the pins.

That plug should have one small pin and three large pins. I have seen no definitive pin numbering, so unplug the speaker cable, and look at the speaker socket from outside the back of the chassis. The pin numbering which I have adopted for that socket as seen from the outside is:

[Image: https://plymouthcolony.net/starcity/radios/images/temp/plug4philco-rev.jpg]

Pin 1 is the small pin. Now let's figure out which speaker leads do what. First, which pin is not used? Leave the speaker unplugged for easy access to the socket pins. By any chance do you have 4-pin and 6-pin tube socket adapters (aka socket extenders)? They would make this easy, but I suspect that many, perhaps most, collectors do not own a set of tube socket adapters.

RE: Philco 144B low volume - Tucker - 06-07-2023

Pin 3 has no wire in the plug.  Sorry, I don’t have a 4 o 6 pin socket extender - only have a 8 pin extender.

RE: Philco 144B low volume - MrFixr55 - 06-08-2023

Try this:

+1 on radioRoslyn's info. take an ohmmeter and connect to pin 3 (screen grid and B+ for the rest of the radio) of the 42 socket, then idetify the speaker wire connected to it (the one that ohms at zero). that wire connects to the speaker connection that is common to the output transformer and the field coil. Then Ohm from Pin 2 (plate) of the 42 and identify that wire. That wire goes to the other connection for the output transformer primary. Ohm from Pin 1 or 4 (cathode) of the 80 rectifier to the remaining wire. It should be zero. Connect that to the remaining terminal of the speaker (the field coil).

Hope that helps.

RE: Philco 144B low volume - radiorich - 06-08-2023

Hello Guys,
yes, my Philco 610b is one those sets where the speaker is hard wired into the chassis .
Far as that plug goes my Ge model L-916 console has one like that .
Sincerely Richard

RE: Philco 144B low volume - DaleHCook - 06-08-2023

MrFixr55 beat me to it in posting the instructions. I must have been pretty groggy when, in my last post, I mentioned tube socket adapters, because all you need to do is pull the 42 output tube and the speaker plug to access their socket pins. Please post your results here so I can add them to my dynamic speaker cabling database.

RE: Philco 144B low volume - Tucker - 06-08-2023

I just checked the tube socket pins and traced them back to the socket. Here’s what I found,  pin 3 of the 42 tube goes to pin 1 of the socket, pin 2 of the 42 tube goes to pin 2 and 4 of the speaker socket, pin 1 of the 80 tube goes to pin 2 of the speaker socket. 
I think something’s wrong so I’ve attached a picture of the back of the output transformer. The green wire goes to pin 1 of the speaker socket, the yellow wire (replaces striped wire) goes to pin 2 of the speaker socket, and the white wire goes to pin 4 of the speaker socket. 
Both the white and yellow wires go to the field coil connections.  The green wire only goes to the output xfmr.  

   

RE: Philco 144B low volume - Ron Ramirez - 06-08-2023

You have your green and white wires switched at the speaker plug. The green wire should go to the 42 plate; the white to the 42 screen grid and one side of the field coil.

RE: Philco 144B low volume - DaleHCook - 06-08-2023

It is the connections to the speaker plug which have me confused. The 42 plate (pin 2 of the 42) should not go to both pins 2 and 4 of the speaker plug. That would short the OT primary, the FC, or both, depending upon how the plug is wired.

RE: Philco 144B low volume - Tucker - 06-11-2023

I just switched the green and the white wires at the plug and the volume is only slightly better.  I also checked all the tubes and the 42 output tube was a bit weak but not bad.  I changed it out with a 42 from another radio  but it didn’t make any difference.

RE: Philco 144B low volume - Ron Ramirez - 06-11-2023

Sounds like it is time to trace the connections on the schematic and compare to what you have. If your current hookup doesn't match the schematic, you will need to make it conform to the schematic. Otherwise, further troubleshooting is in order.