I need a little advice. I have come into possession of a Philco Model 51 Tombstone table model radio. I was told that it worked "the last time it was used,,,they failed to say when that was,,ha) I am interested in restoring it (it works not at all now, the dial light lights up but no tube illumination). I built a "dim-bulb tester" and it indicates that the transformer is shorted. I had planned on reading up and trying the restore myself ( Im no expert but I am a handyman type). However, after reading some of the posts and articles on the net regarding restoring these old radios, it seems as though there might be a "little" danger involved in the line of zapping urself silly! Therefore, would you recommend having someone else do the restore or studying and trying it myself. I know that this is a unanswerable question but I am looking for some knowlegable hints!! Is something like this simply too much for a newbe to try? If so, does anyone know of anyone in the Dallas/Ft Worth area to go to for help and/or restoration. Thanks!
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The dim bulb test will not indicate a shorted transformer per se, but will only tell you if there is a short in the radio. I should point out that even if everything is fine the bulb will still glow, it's more a question of how much and for how long. The fact that the dial lamps glow is an indication that the filament winding should be fine, the bulb acts as a ballast to drop the input voltage, as a result the tube filaments may be too dim to see at first, it will take longer for them to warm up verses the pilot lights. If you have a light bulb in series with the line, you turn the set on, and it glows brightly and stays that way, then there is a short in the power supply section. At this point I would take an ohm meter, with the set unplugged of course, and check each winding, I would also check between the rectifier tube filament and the B-, you could simply check between the positive and negative sides on the filter condensers as well, low or no resistance indicates a problem.
Best Regards
Arran
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Jshivers,
First, let me welcome you to the Phorum. You have come to the right place. If you are good with your hands and have some soldering skills you can probably restore your Model 51 with the help you will get here on the Phorum. It would help if you can use a multimeter. Yes, there is high voltage in these sets, both ac and dc (about 600ac and 300dc) so you have to be careful.
As far as your model 51 is concerned, most often these sets need to have their electrolytic filter condensers replaced, as well as the paper capacitors that are in the tar blocks mounted under the chassis.
You can do all this in good time. The first thing I would do, is remove the 80 rectifier tube and connect your set back up with the dim bulb. Now see if the bulb glows only dim and if the filaments light. That would be a good start. Report back and we can go from there.
Regards,
Ed
Great!!! Thanks for the response. Can you recommend a good book regarding all this?
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I would recommend 'The Elements of Radio Servicing' by Marcus and Levy. You can download it several chapters at a time here.
http://www.antiqueradios.com/archive.shtml
Ed
