Hi Guys, I just got a Zenith 6-B-321.[img]http://www.nostalgiaair.org/PagesByModel/058/M0025058.pdf

I don't know to much about viberators.. I know DC current can not
be transformed. And the vibrator makes pulsating DC. Can this pulsating current be transformed?
Second, can a vibrator be repaired? And how hard would it be to construct a solid state one?
Any help on this subject would be greatly appreciated.
Thanks, Gary[/img]

Vibrator-style supplies were around for a long time. For example, they were universal in old-timer car radios meant to work on 6-volt batteries.

Yes, the "pulsating" (actually interrupted or intermittent) DC can (and does) work a transformer; that's the whole purpose of having the vibrator there. Without it (and the transformer), the high B+ required for the car radio tubes wouldn't be available.

As it "makes and breaks" the DC through the transformer primary, the transformer's field is first created and then collapses. This induces voltage in the secondary winding. It also generates a HIGH-voltage spike requiring use of a buffer capacitor across the secondary. This buffer serves to prevent sparking at the vibrator contacts. The usual value in the old car radios is .006uf at 1600 vdc.

The resultant may be then be rectified like ordinary AC and sent on to the radio.

It is worth noting that the vibrator typically doesn't work at 60 cycles, like ordinary powerline AC. It generally runs higher, somewhere around 105-110 cycles, if memory serves. This is part of the reason why a specially-constructed "vibrator transformer" is necessary. Ordinary 60-cycle transformers won't do. You should find special "vibrator transformers" in any transformer manufacturer's catalog from the 40's on up to the early 70's.



Larry

Thanks Larry, That helps a lot... I have read some recent threads about vibrators..I remember the old car radios giving off that groaning hum when the set was turned on.
I have restored about 25 old tube radios now, but none with a vibrator in them. I expect the one in my Zenith to be non-working,
I love to make thing work..Meaning, I'll try to fix the the non-working vibrator to work again....I hope!!
Can the old can be sawed in two to fix the contacts?

Gary

The vibrator can may usually be safely opened, but carefully.

Whether or not the points are fixable will be another matter altogether.

You might consider some of the new solid-state replacements, unless you're keen on having that buzzing vibrator sound.

Larry

I have repaired several vibrators by opening them up then bend contacts apart and using a point file to clean the points then regap points somewhere close to .005 or even .003 test it then if test ok put it back together

[img][img]http://i588.photobucket.com/albums/ss328/GARYTLANE/DSC01458.jpg[/img][/img]
Hi Guys, I just built this solid state vibrator, and would like to test it out. I'm not quite sure how to hook up the 6V battery. Does the Pos. + go to the red wire going to the R-1 resistor? And where does the Neg - hook to? For the out voltages, do I connect D-3, D-4 and the other grounds all together?
I'm assuming the out puts are at D-4 and the blue dot coming off R-6, Right? What kind of output voltage should I get? AC or a pulsating DC, what setting should I use on my Fluke VOM?
Thanks ever so much for any help, Gary

I recently did some repair work on an old CB radio that used a vibrator power supply.The vibrator that was in it,as well as two old replacements I had in storage refused to start.

I remembered how Curt Reed had once stated that some old manual had given instructions as how to connect a vibrator in series with a light bulb to start them working again.

I posted an inquiry in the forums about this and a few members came back and gave me the details as how to hook this up.Basically.the pulsing AC slams the Hell out of the contacts and cleans them off.The method seems to work,at least for me,because I was able to get all three of the vibrators going again.

I believe if you do a search using the phrase" vibrator rejuvination" you will probably find that post and associated info.Heed the warnings about using this method,it could be dangerous if you aren't carefull.

Basically hook them to your dim bulb tester.
25W light bulb should do it.

Thanks for the info on restoring an old vibrator. But the one in this old Zenith is toast. It is all rusted through, so I thought I would try to build the one, a solid state unit, like pictured above. I just don't know how to hook it up. Will a 6V dry cell like used in lanterns work? HELP!!
Gary

Interesting post, copied that to desktop as I've a couple of car valve sets needing repairing.

Gary, I have never built or tested one of these solid-state replacements, so I can go only by what I see on that schematic.

Inputs from the 6-volt battery will be: positive to pin 1 of the 6-pin plug (red dot/wire), and negative to ground (and yes, all grounds shown on the schematic should be tied together).

Outputs will be: positive, pin 5 of the 6-pin plug (blue dot), and negative from ground.

If this unit is built to duplicate vibrator function, it should discharge pulsating or intermittent DC. When properly loaded, it should give back the 6 volts it gets from the battery, since that is what the rest of the power supply expects to be fed.

If you test it unloaded, the output voltage may soar somewhat, because of capacitor C4. So you'll need a suitable dummy load for testing. You might try a 6-volt bulb first.

A 6-volt lantern battery should be OK for testing, but such a battery won't carry the set in actual service. It can't supply enough current.

Good luck with your testing and be careful ,

Larry

Thanks Larry, that does clear some things up!
Gary

I found that when the vibrator was shot
it had come to end of its life and the vibrating
springs had worn out making the contacts weld
closed Most of the ones were in a rubber foam
sleeve in a can with no good way to close it up.

That was when a lot of 0Z4s were changed as
routine.

The current in the vibrator transformer is AC,
and needs a buffer cap to reduce the spikes on
the secondary which saves the contacts on the
primary.

Note that the capacitors in this design get slammed with a lot of current, so you should use new low-ESr caps-- your basic tiny transistor-radio capacitors might not last more than an hour or so.

first try at posting a print...just a lightly re-drawn version of the
vibrator circuit. I used it in 6S27 zenith with the Radio Shack power fet version of a 2n3055. Works pretty well off a 6v 4 amp-hr gel cell.
http://antiqueradios.com/gallery/v/temp/VIBRA2.jpg.html

well, server appears hung up, but url should bet you there.

Modern SS vibrators use Fet's and not large clunky 2N3055's. Several ARF members have published designs on here, do a search.

I built the same one (2N3055) circuit and it worked very well in my Zenith 6V27. This is to replace a six pin synchronous vibrator. Here is the thread I posted with pics of the construction. I used 2SC3039 tab mount transistors on mine. BTW, the positive voltage is connected to the center tap of the vibrator transformer in the radio.

http://www.antiqueradios.com/forums/viewtopic.php?t=117401&highlight=

I also built the FET version of the solid state vibrator. Here is a thread on that topic.

http://www.antiqueradios.com/forums/viewtopic.php?t=119027&highlight=

Here is the schematic of the one I built. It was designed by Tom Guest. It works very well.

http://antiqueradios.com/gallery/v/temp/New+Vibrator+1.jpg.html

Ed

Thanks Leno..That's the information I need!
I was wondering if a 6V battery charger would work as a power supply?
Like I said earlier I built the solid state unit only I used Two ECG 196 transistors. My set uses a 190-6 viberator whitch is shot!
Say where is the buffer cap?
http://www.nostalgiaair.org/PagesByMode ... 025058.pdf

Thanks to all, Gary

not sure what you mean by buffer cap, but would assume that its the one across the transformer secondary, in this case the 2 C17's

if that's the case they should have a fairly high voltage rating as they will see a lot of spikes and surges. I used 1 kv rated on mine.

The buffer capacitor was 1600 volts, and the capacity was
for timing ; make sure you use the same value as what
came out. Mallory data sheets are on line. There are lists
of what vibrator and what buffer cap was used in farm and
auto radios too.