[Test-Equipment] Slight OT: Simpson leather case

[k4pf at juno.com]

Hi, Mike

Here is a link to an old military manual that covers calibration
of the Simpson 260, and some other VOMs, starting on page 27.
(The Simpson manual is lacking in the calibration details).

https://rapidshare.com/files/1535949238/Multimeters_General_cal_057555.pdf

The Army document number is TB9-6625-2147-35.

One thing to note is that for that model VOM the + terminal 
actually has - voltage on it for Ohmmeter tests 
(reverses what you might expect).
Also, the R X 1 scale can be deadly to transistor tests -
it can put out far too much current for a safe test, about 150mA.
The R X 100 scale is safe for transistor work.

I phoned Simpson once, about 12 years ago, to ask if they had a test
procedure available, because I wanted to "do" my Simpson 270 Series 4,
and the info was lacking in the user manual.
The lady was very sarcastic in informing me that "Our calibration
procedures are for +our+ technicians."  That still wrankles.

To trouble-shoot your ac voltage problem, I would start 
by disconnecting the panel meter and jumper it.  
Then you can safely do Ohmmeter checks
for the resistors associated with the AC voltage scales.
For instance, if the 2.5VAC scale resistor is open, you would get
no reading on any AC voltage scale.)

73,
Ed

> Mike Sloane <mikesloane at verizon.net> wrote <snip>
> I took a look under the covers to see if I could do something about the 
lack of AC measurement, but dealing with that rat's nest isn't for the 
faint of heart. And someone had already been in there and made some 
modifications. So I just closed it back up.