03-16-2014, 09:54 AM
Here's the thing. You have a situation where someone is receiving SW frequencies on a radio designed to receive only the AM band and low end SW of 1.5 to 3 mc. The first thing you want to confirm is that the circuit is as designed by the manufacturer. That means if Philco calls for 700 pF on the cathode of the 36 tube, then you use 700 pF. As for the cathode resistor, Philco called for a reduction from 15K to 10K to help the fussy 36 tube to oscillate properly. It is also documented (I think it's in the Radio Troubleshooter's Handbook) that it may take a reduction in the cathode resistor to 8.2K or even 7.5K to get the 36 tube to oscillate properly.
Baking the oscillator coils is a known, and an excellent, way to remove trapped moisture in the bakelite coil forms. Moisture absorption is known to prevent proper oscillation, especially in 19/89 sets. Just be sure the baking is done before any windings are rewound!
Knowing how much trouble people have with 89 and 19 sets, this is why I published the "Evolution Of" series on my website with schematics of every known variations of these (ditto for model 60). I have to admit, I have only had one 89 (so far) that really gave me fits; its story is chronicled on Chuck's site. I guess I've either been lucky...or methodical repair/replacement/troubleshooting techniques are working for me on these. I happen to really like a good, working 19 or 89 as they are very sensitive radios when properly restored and are perhaps Philco's best smaller radios (they do not have a multitude of tubes, but they just play really well).
If the set isn't working right, then you need to make sure all is as it should be, then troubleshoot to find out why it is not working properly.
If you don't have the parts you need, you will have to order and replace them.
I don't claim to know it all, but I've been puttering around with this junk for 40 years now, so I hope I've learned a little bit.
Baking the oscillator coils is a known, and an excellent, way to remove trapped moisture in the bakelite coil forms. Moisture absorption is known to prevent proper oscillation, especially in 19/89 sets. Just be sure the baking is done before any windings are rewound!
Knowing how much trouble people have with 89 and 19 sets, this is why I published the "Evolution Of" series on my website with schematics of every known variations of these (ditto for model 60). I have to admit, I have only had one 89 (so far) that really gave me fits; its story is chronicled on Chuck's site. I guess I've either been lucky...or methodical repair/replacement/troubleshooting techniques are working for me on these. I happen to really like a good, working 19 or 89 as they are very sensitive radios when properly restored and are perhaps Philco's best smaller radios (they do not have a multitude of tubes, but they just play really well).
If the set isn't working right, then you need to make sure all is as it should be, then troubleshoot to find out why it is not working properly.
If you don't have the parts you need, you will have to order and replace them.
I don't claim to know it all, but I've been puttering around with this junk for 40 years now, so I hope I've learned a little bit.
--
Ron Ramirez
Ferdinand IN