Packard Forum Index » Post-War (1946-54)

HUH!!!!! What he say???

Howard Sams Co put out their SAMS Photofacts for these old car radios, you can Google them and get them from their website... all Radio/TV shops got SAMS as part of a subscription service, they have voltage measurements, schematics, and list of all parts. I use them to restore vintage tube audio equipment, and prefer to use Sprague Orange Drop or Illinois capacitors in the vintage equipment. The voltage rating needs to be equal or higher, the capacitance should be reasonably close to original, but can go a bit higher if equal is not available. Do one at a time and make sure there are no cold solder joints. A good de-soldering tool is handy also.

Thanks for the recommendation on the cap brands. If I decide to go ahead and do mine myself, will see if those are available locally or have to be sourced.

When I was looking for service info for the radio in my 54 Cavalier, I found copies of several Howard W Sams Photo facts on here under service literature.

These radios are very similar in design, so you don't need the exact Sam's

The hardest thing about fixing an automobile radio is getting it out and back in the car.

The model of the radio is usually on a sticker on the bottom viewable from under the dash. Most of these radios are quite similar in design and made originally by Philco or DELCO. These manufactures probably used yet another manufacture to make the radio.

They are all equally good quality. Philco liked to use their Loctal base tubes which are a little scarcer. The circuit design is so standard that a Radio guy won't need a schematic to fix it.

My radio has the WonderBar tuning system which is a complication in its own right and I found original service information on eBay for that. It is not covered in the Sam's

Every Radio/TV shop on the planet subscribed to Sam's so they are prolific.

The components that usually fail are the capacitors, tubes, and resistors in about that order. The Vibrator should be replaced with a new solid state replacement (check the polarity) as originals are long gone and used up.

A competent radio / TV guy should have no problem replacing the capacitors (Re-Cap), and won't need the Sam's. You do need good electronics soldering skills.

The electrolytic capacitors are more difficult to find and we rebuild them in old TV sets.

New tubes and vibrators are generally available from places like Antique Electronic Supply in Tempe AZ. Capacitors and resistors are available from web based electronics suppliers like Allied Electronics and Newark, place the order and get it the next day.

The parts you can't get are volume control potentiometers, (pot's) tuning coils and mechanical parts. Special speakers are hard to find. It is easy to mess up a vol control shaft or stuff a screwdriver through a speaker. Speakers can be re-coned.

To get my radio out I had to move the A/C, disconnect a heater- Bowden cable under the dash while standing on my head with my feet out the window, hanging by my fingernails.

Taking out the glove box / drawer helps.

The antenna unplugs, there is a wire with a fuse for the radio and sometimes another for the dial light. Could be more wires if the tuning is remote or there is a rear speaker. The knobs come off usually with a slot head set screw and a couple of nuts hold the radio in in the dash. The escutcheon comes off the front. There will be a heavy bracket at the bottom with a screw or bolt.

The back of my 54 comes off with two ? screws. You can get the tubes in and out but it is difficult. The tube layout will be on the inside of the lid.
I work in electronics engineering and tinker with obsolete radios and TV's for amusement. (No new patients).

Now that my radio works as good as new all of the listenable AM stations have gone some kind of crap talk,here in Phoenix AZ.

Jim

If a capacitor is suspect it can be tested. You can even use a differential equation to check it.

If you want to do something really neat with that radio you can bypass the receiver/detector and tap directly into the amplifier with a jack in the glove box. Then you can run your telephone, FM radio or portable CD player through the radio amplifier.

I have the service book around here somewhere, but radio stores used to do that with table radios for a fee and sell the customer a phonograph and records.

Also, there is an antenna trimmer that is accessible on the bottom or back of the radio housing. The purpose is to match the radio to the antenna. Usually the radio is tuned to a weak station at the lower end of the AM band, then the trimmer is turned,usually with a small screwdriver, to get the best reception. Correct antenna-receiver matching an make a world of difference in reception quality.

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JW, excellent point and often dramatic improvements in radio performance can be obtained by trimming the antenna. In the V8 Packards access to the trim adjustment is thru the small hole in the top of the glove box.

That's highlighted in the instructions under A8. They say near 1400. That's a standard thing.

When I was a kid I used to screw with the trimmers in my transistor radio to make my favorite station come in loudest. I didn't know what I was doing but it had the same number of trimmers as the Packard radio.

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

Making a device to test a capacitor is not that complicated if you can't find one of the old types on Junk-Bay.

What puzzles me about this discussion is that nobody cares about the voltage chart that is provided. If a component is faulty it will show up in a voltage check and on the waveform.

You can buy portable oscilloscopes that are really fantastic.

30 years ago I bought an old RCA amplifier. It didn't work. It had two capacitors that had dried and cracked. So I replaced them. I had to use the formulas to combine little ones to match what was broken. Then I thought - Oh maybe I should replace these other ones that were standard values. So I did and the sound quality wasn't as good. So I put the old ones back in.

If a capacitor hasn't gone bad by now it probably never will.

A standard radio handbook will contain the process to diagnose specific symptoms such as - Tone Control Not Working.

For example, if you place a wet finger on one of those tube pins the unit should growl. If it doesn't the problem is within one section of the radio.