[ARC5] Vibrator Power Supplies

Wed Nov 22 04:14:43 EST 2017

Actually, only some of the civilian vibrator boxes say to replace the 
buffer capacitor.  Especially the CD ones (they also made capacitors).  None of 
the military ones do.  If the buffer cap is waxed paper, I would  replace it. 
 But in the military sets, which are the only ones I have ever fiddled 
with, you don't find those.  And I can't recall ever having to replace a buffer 
cap.  Although it certainly won't hurt anything to do so.

If the set has sat dormant for 20 to 30 years or more, odds are that the 
vibrator won't work, and it will take more than a few taps to get it working.  
I've been using the light bulb and AC line method for at least 30 years.  
What apparently happpens is that the sponge rubber sleeve that's around the 
vibrator inside the can outgases sulfer and after enough years, a layer of 
tungsten sulfide forms on the contacts.  The roughly 170V P-P plus the 
vibration caused by operating the coil off of raw AC will usually eventually break 
through the layer and the thing will start working again.  It may take as 
much as 12 hours to do it.  The method works on all military vibrators except 
for VB-5, which has an internal resistor across the contact in series with 
the coil which severely limits the voltage that you can get across the 
contact.  And you don't need to use the method on the VB-16 as it has a removable 
cover so you can use a burnishing tool.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 11/22/2017 01:08:33 AM Central Standard Time, 
spr at earthlink.net writes: 
> Hi Richard,
> 
> FIRST THING: replace the buffer cap across the HV secondary of the power 
> transfomer before you apply power. Every vibrator bix says that the warranty 
> is void unless you replace this capacitor when you replace the vibrator.  
> It will probably be rated at 1600V.
> 
> Then try it and see if the vibrator buzzes, and if it makes B+. Sometime 
> you need to tap the vibrator some to clear the oxide film from the contacts.
> 
> I have seen vibrators that will work but he B+ is low; a different 
> vibrator cured that.
> 
> Good luck!
> 
> /scott robinson
> 
> >> -----Original Message ----- 
>> From: kn7sfz 
>> Sent: Nov 21, 2017 7:55 PM 
>> To: arc5 at mailman.qth.net 
>> Subject: Re: [ARC5] Vibrator Power Supplies 
>> 
>> Question for the group.
>> 
>> If one has a piece of equipment with vibrator supply that hasn't run for 
>> decades, what precautions should be made to protect the radio from any 
>> damage when applying power after sitting dormant for so long.  Can't just 
>> bring this one up on a variac.  Car radios, Gonsets, etc.
>> 
>> Thanks for your input.
>> 
>> Richard kn7sfz in Orygun
>> 
>> 
>> 
>> On 11/21/2017 7:41 PM, Robert Nickels wrote:
>> 
>> >>> On 11/21/2017 7:31 PM, Peter Gottlieb wrote: 
>>> >>>> I bet a vibrator driven supply would do a pretty decent job running 
>>>> a modern computer! 
>>>> 
>>> I have a little contraption out in the garage which would make that test 
>>> pretty easy, Peter.   It's mil but I can't recall the model number, but 
>>> it's a vibrator type 110V inverter that runs from 24 volts.    I'll dig 
>>> it out next time I have a chance, never really thought of a use for it. 
>>> The Mallory company made a line of vibrator power supply modules that 
>>> were sold to OEMs to save them the trouble of having to design and build 
>>> their own.   One of the 2Mhz marine radios I converted had one inside, and 
>>> it was a pretty nice compact module (about 3 by 5" and maybe 4" tall) 
>>> that put out 300VDC at maybe 100MA.    They were called "Vibrapacks" and 
>>> evidently were used by police radios, according to this ad: 
>>> 
>>> http://members.iinet.net.au/~cool386/elkonode/rsz_vibrapack_ad.jpg 
>>> 
>>> The boat radio Vibrapack used a synchronous vibrator to perform 
>>> rectification at the same time, which is really a slick electromechanical 
>>> solution.   But the 0Z4 cold cathode rectifier tube was also used. 
>>> 
>>> Lots of mobile ham transmitters were sold in the 50s which could run 
>>> 10-30 watts input using a vibrator supply or as much as 50 or 60 watts if 
>>> you used a dynamotor.    The Gonset twins and a universal mobile supply 
>>> made by James used heavy-duty vibrators for higher power,  perhaps others 
>>> did also. 
>>> 
>>> 73, Bob W9RAN 
>>> 
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> 
> 
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