New Member + First Radio (Philco 60MB) = A lot of questions - Printable Version
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New Member + First Radio (Philco 60MB) = A lot of questions - alecburns - 04-04-2018
Hello Everyone,
This is my introduction post as well as a restoration question post. I've been an antique collector for some years and 'specialize' in antique desk fans. Just yesterday I got this 60MB with a near-mint Shellac container from my capitol city for $40. Since then I've watched a couple series on this type of restoration as well as browsed this forum for some answers. I plan on really only restoring the electronics to make them safe. As for the cabinet, I like the shape that it in and only want to clean the original finish. Now, I'm going to try to diagnose what the issue is with this radio and you all can tell me if I'm way off.
When plugged in the radio has a deep humming noise. It is not affected by the volume control, so I assume it is an issue with the electrolytic capacitors. Besides that, all of the tubes light up. So, my first idea is that once I replace the electrolytic capacitors and other paper covered capacitors, I'll have better chances. As for the action of replacing these things, I would put my knowledge at very basic. I can generically read a schematic, and have very little experience with capacitors, so any tips would be very appreciated.
Thank you all very much...
https://imgur.com/a/g7ZmJ
https://imgur.com/a/UIgYD
https://imgur.com/a/yqacq
Also, is this the right schematic??
http://www.nostalgiaair.org/PagesByModel/793/M0013793.pdf
RE: New Member + First Radio (Philco 60MB) = A lot of questions - morzh - 04-04-2018
Alec
Welcome.
First, let me tell you that plugging in the radio was a very, very bad idea. Please in the future try to resist the temptation of powering an antique radio that has not been recapped and fitted with a good cord. You got lucky but could potentially end up with smoke, radio destroyed, or even fire, house burned down, let your imagination run wild.
Now. When having recapped he radio, and the resistors checked, cord replaced (maybe it's good), tubes checked etc, you will likely find out that some of your RF coils are open and have to be rewound. Philco 60 are known for that.
So. Start from maybe checking the power transformer.
RE: New Member + First Radio (Philco 60MB) = A lot of questions - klondike98 - 04-04-2018
Welcome to the Phorum!
Hearing hum is good in that your speaker is probably working ok. Yes, your first item for restoration would be to replace the electrolytic and paper capacitors. There are several threads on restoration of Philco 60s that have appeared in the last few years (here's a link to mine) and a must read is Ron's Evolution of the 60 that will tell you which version of the chassis you have. There were many modifications and for the 60, Ron has done a remarkable job of documenting them. The electrolytics can be stuffed into the two cans that are on the top of the chassis after you empty them. If you use polarized electrolytics the negative side goes to the center tap of the transformer which is separated from chassis ground by the resistors in #47. There are threads and "how to" on this as well.
Post your progress and questions.
update...morzh posted while I was typing...and he's right...you will want to check your power transformer before you do anything. If all your tube filaments were lighted then you know the primary and the filament secondary section is ok but the high voltage secondary needs checking.
RE: New Member + First Radio (Philco 60MB) = A lot of questions - Radioroslyn - 04-04-2018
Hi and welcome,
Redid a model 66B which uses the same cabinet as the 60MB. Electrically it's very similar but the layout is a bit different as the frequency coverage is a little higher. Still have to remount the trim.
http://philcoradio.com/phorum/showthread.php?tid=17464
Lots of sage advise here.
GL
RE: New Member + First Radio (Philco 60MB) = A lot of questions - alecburns - 04-04-2018
(04-04-2018, 06:20 PM)morzh Wrote: Alec
Welcome.
First, let me tell you that plugging in the radio was a very, very bad idea. Please in the future try to resist the temptation of powering an antique radio that has not been recapped and fitted with a good cord. You got lucky but could potentially end up with smoke, radio destroyed, or even fire, house burned down, let your imagination run wild.
Now. When having recapped he radio, and the resistors checked, cord replaced (maybe it's good), tubes checked etc, you will likely find out that some of your RF coils are open and have to be rewound. Philco 60 are known for that.
So. Start from maybe checking the power transformer.
I advised the owner against doing so but he ignored me. When I plug it in at home, I use a dim-bulb tester. I remember seeing that for the coils the material over time expands, breaking a piece of the winding and causing an open.
I want to replace anything that has a high risk of failing. If the resistors check out fine, is it imperative to replace them still?
When it comes to the power transformer, granted it is in good shape, is it okay if I soak the windings in Sprayon Electrical Insulating Varnish? And if the RF Coils are good, them too? Are they nichrome, or enameled copper wire?
RE: New Member + First Radio (Philco 60MB) = A lot of questions - alecburns - 04-04-2018
(04-04-2018, 06:20 PM)klondike98 Wrote: Welcome to the Phorum!
Hearing hum is good in that your speaker is probably working ok. Yes, your first item for restoration would be to replace the electrolytic and paper capacitors. There are several threads on restoration of Philco 60s that have appeared in the last few years (here's a link to mine) and a must read is Ron's Evolution of the 60 that will tell you which version of the chassis you have. There were many modifications and for the 60, Ron has done a remarkable job of documenting them. The electrolytics can be stuffed into the two cans that are on the top of the chassis after you empty them. If you use polarized electrolytics the negative side goes to the center tap of the transformer which is separated from chassis ground by the resistors in #47. There are threads and "how to" on this as well.
Post your progress and questions.
Thank you!
I can tell someone in the past patched up a couple cuts in the cone. I'm going to check out Ron's post and yours.
I'll be sure to keep the thread posted. Tis project will be a while though haha!
RE: New Member + First Radio (Philco 60MB) = A lot of questions - alecburns - 04-04-2018
(04-04-2018, 06:42 PM)Radioroslyn Wrote: Hi and welcome,
Redid a model 66B which uses the same cabinet as the 60MB. Electrically it's very similar but the layout is a bit different as the frequency coverage is a little higher. Still have to remount the trim.
http://philcoradio.com/phorum/showthread.php?tid=17464
Lots of sage advise here.
GL
I'll give it a look!! Is there a way to "recondition" the grill cloth? I won't experiment with it since I know they dont reproduce the pattern, but if there's a proven method it would be great!
RE: New Member + First Radio (Philco 60MB) = A lot of questions - Radioroslyn - 04-04-2018
>Is there a way to "recondition" the grill cloth?
Generally not. At 86yrs old it's going to b e pretty fragile. Any sort of chemical cleaning will probably cause it to fall apart. Short of vacuuming I think that's going to be about it.
RE: New Member + First Radio (Philco 60MB) = A lot of questions - morzh - 04-04-2018
The resistors are not a hazard. Even if badly out of tolerance. Change only those that are outside the tolerance which could be as lax as 20%.
Leave the trasformer alone if it checks out.
The Rf coils are always copper, never Nichrome if only for the reason of losses in them being undesirable and Nichrome is specifically made to be lossy.
But the insulation between primary and secondary in them is made of celluloid which disintegrates with making nitric acid as a byproduct, which in turn corrodes wires. Look for the green spots on the windings. If seeing any, even if the continuity checks out, rewind the outer winding (more often than not the inner stays ok).