Philco 37-10 magnetic tuning problems - Printable Version

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+--- Thread: Philco 37-10 magnetic tuning problems (/showthread.php?tid=13848)

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Philco 37-10 magnetic tuning problems - Bob Andersen - 01-14-2016

I recently dug into my first Philco - a 37-10 with automatic / magnetic tuning - and set out to restore it.
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It worked fairly well well when I got it then sat in a closet for a few years.  This was my first good luck under the chassis and I was surprised to see so little work had been done to it.  Just a few new electrolytics and paper caps. I later found that the volume and tone controls had been replaced too.

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RE: Philco 37-10 magnetic tuning problems - Bob Andersen - 01-14-2016

Next I recapped it including unmounting the RF unit so I could really get down in there.

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Replaced all the rubber mounts while I was at it.
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All the bakelite and electrolytic caps were restuffed.
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I also discovered the 2M volume control had been replaced with a 500K and the tone/power switch replaced with a potentiometer and switch. I got replacements from playthings of the past and restored the original wiring.

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The radio played great on the first power up Plenty of volume and selectivity. However, the "magnetic tuning" feature doesn't seem to be working.

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Turning it on and off has almost no effect on the tuning. It certainly isn't locking in on a station. I did some voltage checks and found the 6N7 oscillator control tube only has around 180 volts on the plates. The service info states 260. That voltage is derived from the junction of the 10K and 15K in a bleeder network of 10K, 15K and 51K.

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RE: Philco 37-10 magnetic tuning problems - Bob Andersen - 01-14-2016

Huh, it's working now  I just kept poking around and finally got the discriminator coil to peak

Here's a look inside the IF / descriminator can for the curious. The variable cap at the top is the one I had trouble peaking. Maybe my opening up the can and blowing the dust off fixed it ?
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RE: Philco 37-10 magnetic tuning problems - klondike98 - 01-14-2016

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RE: Philco 37-10 magnetic tuning problems - sam - 01-14-2016

Great looking bob
Great vid too
Sam

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RE: Philco 37-10 magnetic tuning problems - Bob Andersen - 01-14-2016

Thanks! Next installment uploading right now where I demonstrate the magnetic tuning. It really does work well once properly adjusted.

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RE: Philco 37-10 magnetic tuning problems - KCMike - 01-14-2016

Very nice job, and thanks for posting the magnetic tuning video.

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RE: Philco 37-10 magnetic tuning problems - w4rtc - 01-15-2016

Hi Bob
Really like your YouTube vedios.   I just finished a magnetic tuning philco, I had to read the alignment instructions several times before I got it right. Especially tuning the AFC. Keep up the good work.
Joe

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RE: Philco 37-10 magnetic tuning problems - Bob Andersen - 01-15-2016

Thanks!  Does anyone know where I can get a new dial glass ?  I suppose I could pick up a piece of glass any try cutting it myself but the curves look tricky

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RE: Philco 37-10 magnetic tuning problems - w4rtc - 01-15-2016

Hi Bob
Really like your YouTube vedios.   I just finished a magnetic tuning philco, I had to read the alignment instructions several times before I got it right. Especially tuning the AFC. Keep up the good work.
Joe

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RE: Philco 37-10 magnetic tuning problems - sam - 01-16-2016

hey bob
I think I have a 38-116 glass around here
that should be the same  yes??

sam

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RE: Philco 37-10 magnetic tuning problems - Bob Andersen - 01-16-2016

Hmm. I don't think so. It looks like the side are straight in the 38-116 while angled a bit in the 37-10. http://www.tuberadioland.com/images/philco38-116x_13.jpg

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RE: Philco 37-10 magnetic tuning problems - Arran - 01-16-2016

Bob;
  Maybe you could trace out the shape onto cardboard and get a glass shop to cut a new piece? That is unless you know someone who does a lot of stained glass work, they would have the tools to cut and grind glass.
Regards
Arran

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RE: Philco 37-10 magnetic tuning problems - Ron Ramirez - 01-16-2016

Bob

Have you considered plexiglass? I cut a piece of plexiglass for that type of escutcheon once, several years ago...it wasn't easy, but a heck of a lot easier than cutting real glass...and looked fine once installed in the escutcheon.

Or if you decide to go with real glass, Arran's suggestion to go to a place that does stained glass work sounds like an excellent suggestion.

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RE: Philco 37-10 magnetic tuning problems - Bob Andersen - 01-16-2016

Thanks for the tips! I'll see what I can do. Meanwhile, I've been reassembling the automatic tuning mechanism and have a few questions.

1. What type of bulbs should be used ? I found two types installed - #44 and some fat 3W bulbs.
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2. There is a chrome reflector ring around behind to station identifier tabs. I'm pretty sure all four bulbs should point towards that reflector but the top two on mine point forward. That only illuminates the inside of the cabinet! Should I bend them so they point into the dial ?
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3. Finally, I'm confused about the audio muting switch. I understand that it should short out the audio to ground when the tuning handle is pressed in. The inner contact on mine is just sort of floating around inside. I think it should line up with the other contact mounted on the shaft. Not sure if I'm missing something that would secure it in position.
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an anyone shed some light on these issue ? Thanks!

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