Re: 1947 Radio

Posted by Jim McDermaid On 2013/12/13 17:16:53

On my 54 Cavalier I can get to the antenna trimmer by removing the Glove drawer (four hex head screws), simple as pie. Remember you have to peak it where you normally have the antenna extended to.

What are called paper type capacitors develop internal leakage due to age. You need a capacitor test set to evaluate them properly and usually need one end unsoldered. Modern meters don't apply enough test voltage to find leaky capacitors.

I find TV's and radio's older than the mid 1950 usually have failing leaky capacitors.

NOTE: they can be leaky and still have proper value.

We in the antique radio-TV restoration hobby usually just replace them all. As long as you unsolder one end you may as well do the other and start new. Capacitors are usually a buck or two each and the new ones last a long time.

There will be a can type electrolytic capacitor, and they are generally unavailable from parts suppliers. So we in the hobby take them apart and stuff in new electrolytics inside the can and put it back in so everything looks original. Sometimes there is enough room to use axial lead electrolytics and just leave in the original. Sometime the original is still good. If the electrolytic has not been used for some years they tend to go bad but we try applying the rated voltage carefully and they often recover.

The Automatic Volume Control circuit (AVC) is the most sensitive to leaky capacitors. The symptoms will be lack of sensitivity. The WonderBar won't trigger often. All radios of this era have AVC which levels out the volume as you tune between weak stations and strong ones.

Be careful as there are very fine wires from the inductive tuning coils to the chassis and the coils are extinct.

Jim