Simpson 260 series 8 calibration instructions (lots of photos, no really..LOTS)

[kj7e]

Picked up a nice Simpson 260 series 8, in good shape, nothing burnt or broken, but was missing the test leads and the the readings where a bit off even for an analog meter. After some playing I found the main issue was the 50uA shunt adjustment which affects all meter readings.  This is adjusted by R1, I found best results when laying the meter flat on its back, properly zeroed first, then adjusted R1 for 80% scale or 40uA on the 50uA range.  This resulted in overall best linearity on all ranges.  Next adjusted R2 for 800uA in the 1mA range. The only other two adjustments are for 2.5v and 250v AC, R25 and R22 respectively.  Both schematics and a US Army Technical Bulletin with some adjustment info attached (below the photos).

Various manuals for the Simpson meters can be found here;
http://www.simpson260.com/downloads/downloads.htm

This series uses the reverse banana plugs, ordered a set of Oldaker test leads off eBay, very flexible and high quality, nice leads.

Since I love photos, here are a few showing the end results, the last time I had an analog meter was back in the 80s, a Micronta 22220.  I'm really impressed with this Simpson after a few adjustments.  I tried to remove some of the parallax with my camera angles.



































































Who needs 7.5 digits anyway?

[xrunner]

Not every shot is perfectly aligned with the mirror but I can tell that it's extremely well calibrated! 

[HammerTone]

Based on your comments I ordered a set of the Oldaker leads .. they are very nice leads!