[Test-Equipment] Triplett 630

[k4pf at juno.com]

> Jeff "W8KZW" <w8kzw at arrl.net> wrote
> I have recently acquired a Triplett 630 (no suffix at all)  
that needs some work.  I believe some resistors on the turret 
have burned out.
A web search produces manuals for  a 630-NA, PL, PLK, Type 5, 
and NS, but nothing with no suffix.
Are any of these consistent with my "plain jain" 630?  
I have an NA so I know that's a different meter.


Hi,

Here is a link to the 630-A.  It is also an early vintage Triplett VOM,
with the same scales as yours, and also has a 20K Ohm/volt sensitivity:
http://bama.edebris.com/manuals/triplett/630a/

Looking at a photo of the original 630 on eBay, and the 630A manual,
I see that they have changed the arrangement of resistors 
on the function switch.  In the original 630, the resistor bodies 
were surrounded by the molded switch body, but in the 630A 
(and newer) Tripletts, the resistor bodies lay on top of the range switch, in a radial pattern.

This shouldn't be a problem, as replacement metal film resistors 
can be smaller for the same power rating as the older 
carbon film resistors used for most of the 630 scales.

The 630A has a 3-pole range switch.  The 630 type 3 (and newer)
Tripletts use a 4 pole range switch, so there is some difference in resistor values for the newer Tripletts.  I assume your 630
uses the 3 pole range switch pattern of the 630A.

73,
Ed Knobloch