MJLorton Solar Power and Electronic Measurement Equipment Forum

General Category => General Discussion => Topic started by: Mr Eastwood on January 07, 2013, 08:23:31 AM

Title: Solartron 7150 DMM (Cal Results)
Post by: Mr Eastwood on January 07, 2013, 08:23:31 AM

I took my Solartron 7150 for a calibration check recently and I've just got it back; these are the results for anyone who is interested.

(http://tinypixels.co.uk/projects/misc/7150_cal_results_full.png)

Title: Re: Solartron 7150 DMM (Cal Results)
Post by: SeanB on January 07, 2013, 10:55:40 AM

So it is correct within 5 counts. Very nice result there. How long has it been since last cal and how old is this unit.

Title: Re: Solartron 7150 DMM (Cal Results)
Post by: Mr Eastwood on January 07, 2013, 11:36:52 AM

Quote from: SeanB on January 07, 2013, 10:55:40 AM

So it is correct within 5 counts. Very nice result there. How long has it been since last cal and how old is this unit.

I bought it from Ebay in June last year for £29;  The meter is 80's I think;  there was a cal sticker on, I believe it was 2006;   I didn't expect too much but I was pleased with the results considering it's age and the Ebay gamble factor!   One thing that did surprise me was the aging tolerances across the ranges and how it soon adds up over the years - so although a unit is within it's specified manufacturers calibration and gets a certificate pass,  it might not be that accurate compared to the original specification.

Title: Re: Solartron 7150 DMM (Cal Results)
Post by: SeanB on January 07, 2013, 12:10:01 PM

So you won the jackpot then. A nice meter well within it's accuracy specs and still usable as well.

Title: Re: Solartron 7150 DMM (Cal Results)
Post by: MJLorton on January 09, 2013, 06:41:37 AM

What a Gem, thanks for the post. In the future I hope to get hold of some older kit as well to show what value can be found....with a little gambling involved...

I noted another viewer commented on my scientific calculator review about some of the older electronic devices he had (digital watch : A Texas Instruments, with red leds)...brought back some memories.

I think I'll start a section for folks to post pictures of any "older" technology they have lying about.

Title: Re: Solartron 7150 DMM (Cal Results)
Post by: Mr Eastwood on January 09, 2013, 07:20:56 AM

An "older" technology section in the forum would be a great idea!



Here's a pic of the 7150 meter with my voltage reference applied.  For the reference I use a Druck Loop calibrator (shown in yellow) for my constant current which just goes into a Time Electronics Resistor decade box;  I got these ridiculously cheap on Ebay!  Once I get a nice reading I write down the values for future reference - it's not an ideal solution but it seems to work.

(http://tinypixels.co.uk/test_equip/v_ref/voltage_ref.png)