03-29-2020, 08:14 PM
Self-quarantined with lots of time on my hands. Decided to take a few Philco boat anchors off the shelf and give them another try. Finally finished the model 89. Had to rewind the oscillator and 1st IF transformers. photo attached.
Decided to take on the Philco CT-2 car radio again. Again, its driving me crazy and I sure could use some input. The oscillator will not run on its own. The transformer is the original and not the new version that was changed (blue coil not red) in the later runs. (photos attached)
I removed it and it looks ok. Numbering from the ground to the top 1-4 it measures
( 1-2… 1.32 ohms ) ( 2-3…3.74 ohms ) ( 3-4…1.64 ohms )
( 1-2…21 uh ) ( 1-3…149 uh) ( 1-4…150 uh)
I removed the C12 & R11 and put in a decade box. The oscillator fired up with 1.4K & .0015uf. However, it will not run with my scope probe removed from the top of R11. I added 2pf which is the scope lead value but no luck. If the oscillator runs, I can drive a signal from the antenna input to the speaker with volume control using the 260kc offset for the station frequency through the center portion of the band So everything else appears to be working. Also tried 3 separate 77 tubes
The lower portion of the coil appears discolored as if it was overheated. I really hate to rewind this transformer; it looks like a pain. I would guess that Philco changed the turns on the newer coil, but I have no idea what they would be.
I could really use some input on this one
Tom
Decided to take on the Philco CT-2 car radio again. Again, its driving me crazy and I sure could use some input. The oscillator will not run on its own. The transformer is the original and not the new version that was changed (blue coil not red) in the later runs. (photos attached)
I removed it and it looks ok. Numbering from the ground to the top 1-4 it measures
( 1-2… 1.32 ohms ) ( 2-3…3.74 ohms ) ( 3-4…1.64 ohms )
( 1-2…21 uh ) ( 1-3…149 uh) ( 1-4…150 uh)
I removed the C12 & R11 and put in a decade box. The oscillator fired up with 1.4K & .0015uf. However, it will not run with my scope probe removed from the top of R11. I added 2pf which is the scope lead value but no luck. If the oscillator runs, I can drive a signal from the antenna input to the speaker with volume control using the 260kc offset for the station frequency through the center portion of the band So everything else appears to be working. Also tried 3 separate 77 tubes
The lower portion of the coil appears discolored as if it was overheated. I really hate to rewind this transformer; it looks like a pain. I would guess that Philco changed the turns on the newer coil, but I have no idea what they would be.
I could really use some input on this one
Tom
