The PHILCO Phorum
40-200 Push Buttons - Printable Version

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+--- Thread: 40-200 Push Buttons (/showthread.php?tid=19160)


40-200 Push Buttons - drrenaud - 10-29-2018

Hi All,
I've just finished restoring a Philco 40-200 and did the alignment and is working great.
Now I'm trying to adjust the push buttons and buttons 1-4 won't adjust below 1200 KHz.
The upper buttons (5-8) work well, I adjusted them 1050-1400 KHz.

Thanks

   

   

RE: 40-200 Push Buttons - Radioroslyn - 10-29-2018

Depends. We need to figure out which isn't tuning properly. Use a counter or another receiver to track the local oscillator frequency and see if it's tuning low enough ( it should be 455kc above the in coming signal . To receive a signal @ 560kc the osc should be running @ 1015kc). If that isn't working properly check 23 and 24 for correct tolerance. This is assuming that the switching and wiring is as it should be.

GL

RE: 40-200 Push Buttons - drrenaud - 10-30-2018

Hi Terry, I checked the wiring, switches and coils and all is well. Each coil is about 3.1 ohms.

Cap #24 = 181.0 pF
Cap #23 = 190.2 pF

I think both caps should be 370 pF, my schematic is not that great and hard to read.

RE: 40-200 Push Buttons - Radioroslyn - 10-30-2018

For a better schematic go to http://www.audiophool.com/Philco.html  Scroll down to 1940 and click on 40-195/40-200.

I'd replace those to caps w/ 370mmfd. Not have enough capacity there more than likely would be the cause of the lack of the low frequency oscillator coverage. Come to think of it my 41-300 buttons won't tune below abt 700kc. Can't get down to the Grand Ole Opry on WSM out of Nashville Tenn.@ 650. I should have a look at mine.

We are Hams we can fix anything!!!   [Image: http://philcoradio.com/phorum/images/smilies/icon_twisted.gif]
de N3GTE

RE: 40-200 Push Buttons - drrenaud - 10-30-2018

Hi Terry,
I replaced both caps with 370 pF caps and now I'm am able to tune through the whole BC band.
Thanks a lot for your help.

RE: 40-200 Push Buttons - jcassity - 10-31-2018

is this a safe plugin to download in order to get the document you posted Terry?

>>>>>>>>LizardTech DjVu browser plug-in

also,,, never seen a skinny domino cap like the one top center of your underside of the chassis!

RE: 40-200 Push Buttons - Radioroslyn - 10-31-2018

Been using it for yrs and haven't had an issue.

RE: 40-200 Push Buttons - Arran - 11-01-2018

I don't know how the pushbuttons are designed in the 40-200, but in some sets it's quite normal for there to be a range for each pushbutton,
so the lower ones won't tune in anything above a certain frequency, whilst the upper ones won't tune bellow a certain frequency. These are the banks that have an oscillator coil for each button, with a slug, and a trimmer, and they are electrically switched in and out of the front end. Some Philcos don't use this setup, they switch in a trimmer, and or a padder for each button rather then a coil, in which case each button should work across the dial.
Regards
Arran