[R-390] Cheap find!

[John Kolb]

The diodes say 6642?  I wonder if that's a date code, 42th week of 1966?

John

At 06:37 PM 3/21/2009, Joe Foley wrote:

>The Mennonites were having a "Free Market" in town so I went to see 
>what might there and I found a B&K 120 "Laboratory" VOM, they said 
>it was a FREE Market so everything was FREE!
>
>So I took it home thinking it couldn't possibly be any good.  I 
>opened it up and found it to be VERY clean inside, smells new, even 
>though it had batteries in it that were old enough to have the price 
>of 20c each on them!  They looked to have been original 
>equipment!  They hadn't leaked at all!  Now, just where am I going 
>to find that 15 volt hearing aid battery??  I'm trying to date this 
>thing, looks like early '60's.
>
>So far it seems to work on DC and Ohms but any AC makes it buzz and 
>the needle twitches back and forth, must be the 6642 diodes are 
>shorted.  The switches are stiff but the zero adjust pot is dirty.
>
>The impedence is only 20 KOhms/volt on DC so it will only be good 
>for use on old equipment when comparing to manual values or for power circuits.
>
>Ya' just never know where this stuff will turn up!
>
>Joe
>
>PS, major Boatanchor-type thing,....... Bell hunting!
>
>1852 Buckeye Bell Foundry
>1900 McShane
>1924 Watervliet, NY
>