Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Pushbutton tuning problem
#1

I have restored a Philco model 41-296. The circuitry in this radio is very similar to several Philcos made in 1940 and 1941. It has seven tuned circuit pushbuttons.

The radio works perfectly in all respects but one. Although the three lowest frequency pushbuttons are clearly labeled as tunable down to 540 kHz, I can't get any of them to go lower than about 640 kHz. They all exhibit this same problem.

The ceramic trimmer capacitors associated with these buttons are antenna trimmers only and have very little effect on the tuned frequency. They have a great effect on how well a station comes in after tuning it in.

It appears that, in pushbutton mode only, the local oscillator just won't tune low enough. Any suggestions are most welcome.
#2

I don't have a schematic of the 41-296 but if it is similar to other Philcos of that vintage the fixed capacitor that is usually connected on the coil assembly in parallel with the coils is bad or has changed value. Most are 360 uuf. Replace it with a silver mica cap.

Kind regards,
Terry
http://home.comcast.net/~suptjud/
"Life is simpler when you plow around the stump."




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
B&K 1077B no video
Hello Tim, I would if it's a leaky Capacitor So are all 3 of those B- voltages low then ? Sincerely Richardradiorich — 01:55 AM
B&K 1077B no video
I found a schematic and think I have the problem traced down to the minus power supply. I have very low voltages that go...TV MAN — 12:41 AM
RCA 15X
I'd try replacing the bulb first and if that doesn't do it, then change the 35Z5 and see if the problem goes away.NostalgiaRadioTime — 12:28 AM
B&K 1077B no video
Hello Tim, I have that exact unit in my shop too plus a Sencore unit there are times I like one or other !!. Sincerely...radiorich — 11:07 PM
RCA 15X
Everthing goes at once, maybe it's the cold weather, I have had 2 dial strings break and no my little RCA is having dial...Paul Philco322 — 10:26 PM
Philco 91 Schematic
Hi Dan, I can't explain this specific resistor but I have seen the use of a switch to apply B+ voltage to screen gri...RodB — 09:36 PM
6TPZ and 5TPO Radio Help
I suspect it's been repaired before. And I suspect whoever repaired it, wanted to re-use old transistors' pin stubs in o...morzh — 09:24 PM
B&K 1077B no video
Thanks Rich! I'll take a look and see what he has. I know there's more modern equipment to be had, but this one I know a...TV MAN — 09:11 PM
B&K 1077B no video
Hello Tim, Here is a link to restoration of one on Phil's old radios site ! Sincerely Richard bk1077bradiorich — 09:01 PM
6TPZ and 5TPO Radio Help
I'm a little befuddled on this one. Should X5 and X4 be tied together like this?  It looks like someone added this at so...R3Sons — 07:33 PM

[-]
Who's Online
There are currently no members online.

>