Products > Test Equipment
Repair of a Vintage Simpson 461-2 DMM
macboy:
--- Quote from: Smith on February 13, 2015, 06:59:40 pm ---These icl series chip fail quite frequently. Most just show strange values (or strange digits) or show non linear behaviour. Havent seen any draw too much current though.
A lot of (older) 3,5 - 4,5 digit lcd voltmeter modules use these chips too. Thankfully you can still get new chips after 15-20 years.
--- End quote ---
Oh I think it's been closer to (maybe over) 40 years since those exact chips hit the market. I have a couple around 30 years old.
Panchdara:
Well done! When you started you mentioned the movie "The Money Pit".. well, is your new nickname Walter Fielding? (Hope not) (But it was funny watching that turkey fly!)
:-+
xrunner:
--- Quote from: Panchdara on February 24, 2015, 10:20:15 am ---Well done! When you started you mentioned the movie "The Money Pit".. well, is your new nickname Walter Fielding? (Hope not) (But it was funny watching that turkey fly!)
:-+
--- End quote ---
LOL - thanks.
OK - it's certified as working now! I also dug out a 7.5V wall wart from my junque box and made up an AC adapter for the thing.
All I have to do is put it back together (without anything else breaking) and see what we got. :)
xrunner:
Well it's put back together and it works like a champ. Got the calibration tweaked up and pretty satisfied with that. Parts required were:
ICL7107CPLZ Intersil Analog to Digital Converter + socket
Two HP hp 5082-7731 vintage seven segment LEDs
2N2907 PNP transistor
7.5 V wall wart for external power
Simpson test lead set in transit from Chile (thanks Lightages).
First pic checking cal
Second pic shows it atop another similar meter in Simpson's line - the 467.
lowimpedance:
Doesn't that look great, and still useful :-+.
However the last pic is not complete yet............... needs a 'nixie' Simpson (did they ever make such a meter ??!.), and a moving coil meter for completion.
I like the oldies too, Well done.
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