[volt-nuts] Solartron Schlumberger 7150 (and Plus) Coto 7002-5086 reed relay in Ohms circuit

David C. Partridge david.partridge at perdrix.co.uk
Fri Mar 4 14:22:27 UTC 2011

Some while back I asked on several lists about a replacement for a Coto 7002-5086 reed relay to repair the Ohms cricuit in these meters.  A kind soul sent me one they removed from a scrap meter, so I didn't pursue it very hard.

I was recently contacted by someone else with same failure in a 7150.  So I contacted Coto and asked - what to replace this with?   They took a while to reply as they had to locate the original documentation and then scan it.  They were not even sure if they'd ever made it in production quantities (I let them know that they did)!

Lee Cota of Coto very kindly sent a scan of the original specification drawings from 1982, which I have uploaded to my website:


That same email also indicated that it can be easily replaced with any of the following standard products: 







I've also uploaded a two page document on the 3500 series relays to my website:


David Partridge

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