Two interesting items just picked up - Page 1
Forum section: electronics / testgear

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 12, 2016, 12:46:14 am
content: The university I work for just had a surplus sale and I picked up a few thingsThese two items were about $1/each and I got them just to look at, and I like the case on the one.The Fisher Scientific Digital Conductivity Meter is not that exciting except they made a big deal of it being NIST traceable (calibration date on back was in 2003) . It is made in an off the shelf box that was missing its battery cover. I would swear I bought this same box from Radio Shack in the early 1980's. It seems to work but there is no probe. Inside there is an Inerstil processor under the LCD which I seem to recall was a popular choice on some multi-meters back in the day. I'm not sure what to do with it now. It might be fun to repurpose the LCD module.

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 12, 2016, 12:51:51 am
content: The CB Sciences ETH-200 - I got this for the case. It is some sort of amplifier for bio-medical sensors. The case is about 6"x6"x2.5" with a card slot in the bottom. It should be nice for a project box. When the box was opened I was very surprised by the condition of the PCB. It looks like the unit was dropped hard enough to pop the PCB out of the card slot and it would up looking like a potato chip (a crisp for the Brits). I was pleasantly surprised to find the Bournes 10-turn 10K pots on the front panel and CK three position switches. All the parts on the CPB look like top quality and the PCB looks to have been all hand soldered! The board had a 1995 date on it.

author: Vgkid
author_rank: Super Contributor
timestamp: September 12, 2016, 02:33:50 am
content: I would be curious if any solder joints broke on that amplifier.

author: radhaz
author_rank: Regular Contributor
timestamp: September 12, 2016, 05:55:25 am
content: You have the beginnings of a box of parts.

author: Richard Head
author_rank: Frequent Contributor
timestamp: September 12, 2016, 06:35:34 am
content: JeffThe Intersil chip is probably the ICL7107. It was very popular for many years but has been replaced by microcontrollers now.The enclosure is the same type used on the AADE inductance/capacitance meter I have. I don't know the manufacturer but I'm sure it's a common box.Dick

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 12, 2016, 12:20:44 pm
content: Quote from: Vgkid on September 12, 2016, 02:33:50 amThe board looks to have been hand soldered and the flux not cleaned up. I would have to clean the board before trying to inspect the solder joints. All of the ICs are socketed and are all now askew in the sockets. The plastic of the PCB mount connectors was also pulled loose from the pins which pushed the connectors partially off as well.QuoteI pulled a Fluke 8010A apart last night that I got at the same sale, it uses the same Intersil chip (complete with 20MegOhm and conductance mode) and nearly the same LCD. I guess Fisher Scientific just brushed off a 30 year old design for their box.

author: dom0
author_rank: Super Contributor
timestamp: September 12, 2016, 04:44:35 pm
content: The amp is likely a low-frequency bridge amplifier for things like strain gauges...https://www.iworx.com/products/legacy/eth-200/QuoteThose two are probably swappedQuoteDecent enough. Although today that's not very much worth in parts. Maybe 40-50 euros per channel for an equivalent device. It is unlikely to be of much use as a general-purpose diff amp in an electronics lab. though.