My first post and of course i have questions. I have reworked a few radios over the years, used to love it, got to working everyday and such, lost track, but now i have time, and I have my 12x24 shop cleaned up and my stuff setup so I can work on radio's again. And schematics seem to be a problem, well i bought a flash drive on ebay, a couple cd's on ebay, and still can't find a schematic in all that for this particular Philco I felt sorry for at a local hamfest yesterday for 15 bucks.He was asking 25 . it is a 39-85 code 121, No B after the 85, I didn't need it, i have a boo coo of radios but since it is battery,that is what i prefer, i am ,please forgive me, a bigger fan of RCA farm radios but have numerous Philcos and enjoy them to. This 1 drew my attention because of the low price. BUT I didn't realize the push button tuning was unhooked, no "obvious" battery connections, speaker unhooked, in other words, A mess.
So if you could find it in your hearts to help me figure this 1 out I would appreciate it.
Part of why I was retired years ago is because of a brain injury so if you can, bear with my grammar and seemingly simple questions.
First off, welcome to the Phorum of Phrindly Philco Phans. (Notice a pattern here?)
Second, God bless you and continued prayers for your recovery from your brain injury!
Third, that IS a rather handsome set.
Fourth, here is a link to the service notes from the Phorum's library. https://philcoradio.com/library/download...20Book.pdf
God bless the Nostalgia Air folks for the great free service that they provide, but some of those schematics are rather fuzzy.
I have 3 RCA Farm (Pharm?) sets, a 1937 5BT and a 1936 6BT both with 2V tubes and a 1940 14BT2. Interestingly, the 5 BT uses a 19 dual triode output while the 6BT uses 2 49 triodes in Class B Push Pull. These sets can be quite loud at 2watts. The 14BT2 is a 4 tube set with similar 1.4V tubes as your Philco. These sets have much lower power output than those big RCAs with the 2V tubes.
These are not terribly hard to deal with. the filaments will run off a 1.5V alkaline D Cell for a rather reasonable time. You can get the 90V from 10 9V batteries or from either a homebrew, vintage or ARBE III power supply.
To figure out what goes where, look at the power switch and trace the wires, or just ohm... Resistance between ground and one of those red wires should be very low with the tubes in place and infinite with the tubes out. Between chassis ground and that wire would be the 1.5V for the filaments. The other wire going to the switch should be the B+. trace the wiring. The B- does NOT go to the chassis but to an 800 Ohm resistor. One end of the resistor is the B Battery negative connection and resistors to supply grid bias to the output and possibly 1st amp tube. The other end of this resistor goes to chassis ground and is the B-. This can be figured out with the help of the schematic.
Replace the electrolytic cap that goes between B+ and chassis ground. It's a good idea to replace all of the paper caps, but they are less likely to go bad in these sets than the line powered sets that generate much more heat. However, best to replace them.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
(This post was last modified: 07-16-2024, 07:17 PM by MrFixr55.)
thank you for the help and welcome.
RCA 14BT2! YES< that was the first radio I ever restored back in high school,Actually got my picture took and a half page about me and that radio in the high school annual! Sits in the living room now. I was told by the old man i bought it from it was 1936, but as life and time have passed i do believe it is a year or 2 newer.I was about 15-6 when I bought it for 30 dollars.
sorry to get off brand with my post but wow, another 14BT2 ,couldn't help it
Nothing wrong with RCA sets, or G.E ones for that matter, in Canada they are pretty much the same thing in different cabinets. I have a soft spot for old tube battery sets, and portables, unless they have been stored improperly, or abused, they are usually in better condition then their AC counterparts electrically, low hours, lower voltages, and low heat tend to help. It looks like someone cremated a resistor, I'm guessing that was in the B- circuit.
Regards
Arran
