08-21-2024, 07:13 PM
Right up front, sorry for all the information in this post, but wanted to provide as much as possible.
I just finished getting my Model 512 working, thanks in a large part to Ron's updated schematic!
I was planning to test it with the matching speaker, but it shown open, so I used a Peerless 7-A, with good success.
I believe that this Philco Speaker is a Timmons Talker Metal case Cone speaker in disguise. It has the Timmons name stamped on the brown laminate in the picture. The speaker looks identical to the one in Buford's Classic Cones, without the red paint. It is also shown on the RadioMuseum.org site for the Model 512.
As I dug into this, I couldn't make sense of the wiring, although it is pretty simple. (A Note here, there was a sticker from 1932 indicating a Radio Shop did some repairs to this set, on the inside of the lid to the radio. Not sure what was done.)
I am assuming that the black cylindrical device is a transformer. I read 238 ohms across the top 2 pins and approx. 0.3 ohms across the bottom two. This doesn't make sense to me, since the speaker cord is connected to the top and bottom pins on the left side. I get no resistance readings on any other combination. i thought 238 ohms seemed too low, expecting something in the 1k range. AND based on the reading, I would have expected the speaker cable to be connected across the top terminals of the transformer. Any thoughts on what the resistance/impedance ratio should be?
I also don't get any reading on the 2 terminals at the right, on the brown phenolic. I'm assuming there is a coil inside there, but didn't want to start tearing into things before I get some info from the experts. If it is a coil, any thoughts on rewinding?
Any ideas? Thanks in advance!
I just finished getting my Model 512 working, thanks in a large part to Ron's updated schematic!
I was planning to test it with the matching speaker, but it shown open, so I used a Peerless 7-A, with good success.
I believe that this Philco Speaker is a Timmons Talker Metal case Cone speaker in disguise. It has the Timmons name stamped on the brown laminate in the picture. The speaker looks identical to the one in Buford's Classic Cones, without the red paint. It is also shown on the RadioMuseum.org site for the Model 512.
As I dug into this, I couldn't make sense of the wiring, although it is pretty simple. (A Note here, there was a sticker from 1932 indicating a Radio Shop did some repairs to this set, on the inside of the lid to the radio. Not sure what was done.)
I am assuming that the black cylindrical device is a transformer. I read 238 ohms across the top 2 pins and approx. 0.3 ohms across the bottom two. This doesn't make sense to me, since the speaker cord is connected to the top and bottom pins on the left side. I get no resistance readings on any other combination. i thought 238 ohms seemed too low, expecting something in the 1k range. AND based on the reading, I would have expected the speaker cable to be connected across the top terminals of the transformer. Any thoughts on what the resistance/impedance ratio should be?
I also don't get any reading on the 2 terminals at the right, on the brown phenolic. I'm assuming there is a coil inside there, but didn't want to start tearing into things before I get some info from the experts. If it is a coil, any thoughts on rewinding?
Any ideas? Thanks in advance!
Thanks
John N3MUN