[Milsurplus] Vibrator failure

[J. Forster]

Thank you for the confirmation. These lists are wonderful.

To progress to the next level, I am very disinclined to substitute solid state
replacement because of the transformer resonance issue. Does anyone know if
there is a design which has the same commutation properties as a mechanical
vibrator? I am beginning to suspect that the buffer cap may well alter the
vibrator's operating frequency a bit, and this might be quite critical.

Unfortunately, some vibrators are solid unobtanium.

Thanks,
-John


aGEnuine Ham wrote:

> John:
>
> One reason the "ACC." position* was developed for automobile ignition
> switches was vibrator failure during the voltage dip when the starter is
> engaged.  It also reduces the battery load during cranking, and that is
> an understandable explanation to a mechanic, so it is the one usually
> given.  You see, the vibrator does not have enough drive voltage to the
> reed, and the back contacts weld together, leading to the destruction of
> the vibrator, and the transformer if the fuse is too large.  It also lets
> the smell out of the radio.
>
> Now for the milsurplus content.  I had a cousin who was a paratrooper in
> Korea, and he once told me that they had a radio in their Jeeps which
> experienced this problem with vibrator contacts sticking when the radio
> was left turned on during starter engagement, and there was a field mod
> which came out to overcome the problem.  I do not remember the specific
> circuit, but I do recall it seemed overly complicated to me.  This ring a
> bell with anyone?
>
> *The power is removed from the accessory connection when the starter is
> engaged, and only the ignition (and fuel pump etc. these days) is left
> connected during starting.  Some of the automobile trade school texts
> from the 40s and 50s explain this a lot clearer than I can.
>
> 73,
> George
> W5VPQ
>
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