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Radio Vibrator

Started by bcroe, April 23, 2013, 04:18:16 PM

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bcroe

I was wondering, what the last year of the (vacuum tube) vibrator supply was?  My
56 has one; 62 does not. 

Also, I have read of vibrators stored a long time, failing to operate.  I expect this is
the same problem as with Ign points; a thin layer of oxide forms on the contacts and
the low battery voltage can't break it down.  I have saved points by applying a current
limited high voltage, burning through the oxide to get them going again.  I might try
that on a vibrator too, if I had one like that (not completely burned out contacts). 

Bruce Roe

Doug Houston

Vibrator contact points have a different problem than the distributor points. Distributor points will, as you've said, form a little oxide barrier on them in some environments, and fail to make contact.

Vibrator points are sealed in a metal can, with a sponge rubber sleeve inside it. This is for the purpose of quieting the vibrator buzzing sound, which would be annoying with the radio working. There is a certain amount of sulphur in rubber compounds, and the points will tarnish considerably if they aren't used for a long time (typically 2 years or more).

There is a method, crude as it is, for reviving a vibrator. It involves applying a DC voltage to the pins of the vibrator in pulses to burn a little hole in the breaker contacts of the vibrator, until the vibrator begins to operate. This is necessary on NOS vibrators as well as ones in your sets.

The '56 set uses a 3 pin vibrator (12 volt). I forget which 2 pins you pulse the contacts with, but I believe that the center pin and one of the others will pulse the contacts (you can feel the reed, operating inside upon applying voltage). It may be necessary to diddle with the thing a lot, before it breaks into operating, but when it does, STOP!.

When the vibrator starts, put it into the set immediately, and run the set for at least 15 minutes.  That will burn away the oxide on the contacts, and the vibrator may give several years more service. If the vibrator is put into a tester, you can watch its output go up as it runs.

Before doing all of the above, replace the buffer condenser. It's the one that connects across the high voltage winding on the power transformer. You can count on it being either badly leaky, or shorted.
38-6019S
38-9039
39-9057B
41-6227D
41-6019SF
41-6229D
41-6267D
56-6267
70-DeV Conv
41-Chev 41-1167
41 Olds 41-3929

dplotkin

I believe the vibrator was gone after 56 and 57 was the first of the hybrids, tubed sets with a semiconductor vibrator replacement and a transistorized output amp.

Dan
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

Jon S

1958's had vibrators.  I believe 1959's were vibrator-less.
Jon

1958 Cadillac Sedan De Ville
1973 Lincoln Continental Coupe
1981 Corvette
2004 Mustang GT

bcroe

Quote from: Doug Houston on April 23, 2013, 06:11:05 PM
Vibrator contact points have a different problem than the distributor points. Distributor points will, as you've said, form a little oxide barrier on them in some environments, and fail to make contact.

Vibrator points are sealed in a metal can, with a sponge rubber sleeve inside it. This is for the purpose of quieting the vibrator buzzing sound, which would be annoying with the radio working. There is a certain amount of sulphur in rubber compounds, and the points will tarnish considerably if they aren't used for a long time (typically 2 years or more).

There is a method, crude as it is, for reviving a vibrator. It involves applying a DC voltage to the pins of the vibrator in pulses to burn a little hole in the breaker contacts of the vibrator, until the vibrator begins to operate. This is necessary on NOS vibrators as well as ones in your sets.

The '56 set uses a 3 pin vibrator (12 volt). I forget which 2 pins you pulse the contacts with, but I believe that the center pin and one of the others will pulse the contacts (you can feel the reed, operating inside upon applying voltage). It may be necessary to diddle with the thing a lot, before it breaks into operating, but when it does, STOP!.

When the vibrator starts, put it into the set immediately, and run the set for at least 15 minutes.  That will burn away the oxide on the contacts, and the vibrator may give several years more service. If the vibrator is put into a tester, you can watch its output go up as it runs.

Before doing all of the above, replace the buffer condenser. It's the one that connects across the high voltage winding on the power transformer. You can count on it being either badly leaky, or shorted.

I believe all vibrators with the standard 4 pin layout, have only 3 pins connected.  I'd like to try
to change the diddle thing, to a more methodical process.  Probably build something & release a
circuit if it works OK.  Should work on 6 pin vibrators as well, with pins translated.  Bruce Roe

Walter Youshock

The '57 Brougham was the first solid state radio.  The standard line used the vibrator through 1958 and it was gone for 1959.  For some reason, the Brougham radio was not able to use the foot control--it would immediately blow the fuse.  However, I believe there was a provision for the foot switch plug in the back of the set (as people tried to plug them in.  This problem was covered in the Serviceman.)

Doug is the radio guru.  For reliable service, any radio this old should be gone over.  When I had mine done, I went with a solid state vibrator which has been reliable for 20 years now.

The '59 radio was solid state (more or less) and accommodated the foot switch--one of the neatest features you can easily add.  We had a '77 Chrysler Newport that had a foot switch.  Cadillac still offered it up to 1970 or even a bit later.
CLC #11959 (Life)
1957 Coupe deVille
1991 Brougham