Analog VOM Calibration

[Rusan]

I have a Simpson 260-7, that was gifted to me by a dear friend. Its readings disagree considerably with my BK Precision bench meter and various handheld DMMs, so it definitely needs calibration.

I don't have precision current shunts or other calibrated/certified standards, plus my benchtop power supply has broken down again and I refuse to fix it yet again but haven't procured a replacement yet. Does anyone know of a reputable test equipment metrology shop in North America that could properly calibrate the Simpson? The only place I could find online is TRANSCAT, which only deals with businesses and has a 6 month lead time at present.

I'm sure I could do a fairly decent job on most of the functions/ranges myself after getting a new benchtop power supply, but I'd rather just have it done by an experienced professional who knows these meters and has the proper equipment.

Rusan

 

[Gold]

I looked into this in the past. IIRC there were a number of different versions of the Simpson 260. Some are easier to calibrate than others. I think the Simpson 260 I have looked like it would be a safer bet to just buy a new one. I couldn't get a firm quote.

The Triplett 960 I have is a very old one. The only way to calibrate it is to hand select components. Later ones have trimmers I think.

 

[Rusan]

My 260 (7 Series) has trim pots for calibrating certain functions, but relies on the accuracy of unselected, low-tolerance fixed resistors for others. That's another nudge to having a professional calibrate it, so I won't have to pay $20 shipping costs on a few .1% resistors that a pro will already have on hand.

Rusan

 

[JohnRoberts]

Don't throw away your old Simpson 260... I learned on one, and miss it.

You can read diodes or transistor junctions on the low ohms scale (or at least you could 50 years ago).

JR

 

[Ricardus]

Don't throw away your old Simpson 260... I learned on one, and miss it.

You can read diodes or transistor junctions on the low ohms scale (or at least you could 50 years ago).

JR

My dad still has 4 of them or so kicking around the house. And then I found another one mint in box and got very excited.

 

[Rusan]

....And then I found another one mint in box and got very excited.

Mine is also in the original box, with the manual and warranty registration card still inside. An amazing find, considering it was made in 1983. But, it's even far more amazing when you know the story of where it came from! Believe it or not, my friend's son found it in a trash dumpster. He gave it to his father, who already had a Simpson 260 and thought I might appreciate having one. I'm definitely blessed and very fortunate to have a friend like that!

I can't remember what was wrong with it, but it was non-functioning when I received it. However, I do remember that it only took a few minutes to find the problem and fix it. I can assume the owner didn't know how to repair it and decided it wasn't worth fixing, so they disposed of it. It's therefore obviously been used, although it appears to be in brand new, 100% mint condition; very clean, shiny and no scratches whatsoever.

Being a Series 7, it has the Simpson reverse banana jacks. I fabricated and installed some adapters, so it could be used with regular banana plugs. Now, it just needs a good calibration, as someone has obviously botched the trim pot settings at some point in time.

Rusan