[Milsurplus] Vibrator for PP-114B Power Supply wanted

Sun, 29 Feb 2004 12:54:24 EST

Wim,

I thought that I had a few left but my database says not.  The correct Signal 
Corps stock number is 3H6691-17, not -L7.  Any make vibrator with that part 
number should work, including the French one.  Other manufacturer's part 
numbers that I know of are ATR 146-B and ELIn 1642.  There may be others that I 
haven't come across.

There are a number of 7-pin vibrators other than the 3H6691-17 but if the 
French one is known to be that part number, the most likely problem is that the 
contacts are oxidized.  Pin 7 is the common pin.  There should be continuity 
through the coil between pins 3 and 7.  If there is, then the vibrator is at 
least a Shunt Drive type and if it has a 6 Volt coil should probably work.  If it 
doesn't, probably the contacts are oxidized.  This is becoming a problem with 
vibrators made in the 50's, especially NOSB ones.  Ten years ago, it was 
mostly only those made during WW-II.  You can clear the contacts mechanically by 
opening up the can and using a burnishing tool.  However, getting the can open 
in such a way that you can successfully close it again can be tricky.  And if 
the aluminum has gotten brittle, it will break instead of bend as you try to 
open.  You can also usually clear them electrically with the 25 Watt lamp and 
AC Mains technique.  I've never tried it on 220 Volt mains but see no reason 
why it shouldn't work so long as you use a 220 V lamp.

There are several other 7-pin 6 Volt synchronous vibrators, the most common 
probably being the 3H6690-15 used in the DY-88, PP-109 and some other Korean 
War supplies.  However, this vibrator was made in both Shunt Drive and Series 
Drive depending possibly upon manufacturer.  The supplies that used it were 
wired to accept both.  The PP-114 is wired only for the Shunt Drive type.  Whether 
the Shunt Drive 3H6690-15 would work in the PP-114 I don't know.  I guess 
that it might but I've never tried it.

In a message dated 2/29/2004 3:42:37 AM Central Standard Time, 
[email protected] writes: 
> For a vibrator power supply PP-114 B/VRC-3 (part of my BC-1000 set) I am
> looking for a couple of spare vibrators.
> The present vibrator is a 6 V DC vibrator 7 pins
> stock number 3H 6691-L7
> Model S-168V
> Made by Vibration Research Labs inc.
> Tuckahoe NY
> Anyone familiair with this model ?
> Is there a equivalent for this model?
> I tried to use a French make, but that doesn't work.

Robert & Susan Downs - Houston
<http://www.wa5cab.com> (Web Store)
<[email protected]> (Primary email)
<[email protected]> (Backup email)

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