Gas Chromatography Amplifier Extreme Teardown - Page 1
Forum section: electronics / testgear

author: rolycat
author_rank: Super Contributor
timestamp: May 21, 2014, 09:04:26 am
content: I was about to strip this old amplifier for parts and saw how beautifully constructed it was internally. It seemed only right to record its passing with a quick teardown:It's an AMS F.I.D./N.P.D. amplifier , used for flame ionization and nitrogen-phosphorus detection in gas chromatography (about which I know very little). I wasn't able to find any documentation on the net.The grubby and deceptively dull front panel.That zero adjustment knob is connected to a ten-turn potentiometer, and the knobs are all high quality collet types.The back:The TO-3 can is a 7815 15V regulator.Inside - a Eurocard sporting an intriguingly solid shielding can, linked to a backplane via the usual DIN 41612 connectors:The 64-way connectors are severely underutilized, each sporting about eight connections.And beneath the shield:The money shot. An Analog Devices 310J electrometer op-amp module, linked to the detector inputs via Teflon coaxial cable, Osmor reed relays and Welwyn high voltage resistors (rated at up to 28 kV). The input resistor values range from 5 megohms to 5 gigohms.Handsome rear panel wiring, showing the numbered input connectors and an earthing point:...of which there are many:The backplane, which has the power regulation circuitry and another four fuses to add to the two on the back panel:The main circuit board out of the case:And finally, a sad little salvage pile:(This in addition to a hefty transformer and three circuit boards.)How much did this jewel of electronics engineering cost? I picked it up off the grass at the Dunstable Downs electronics car boot sale mentioned recently by Mike Harrison (mikeselectricstuff). The owner had abandoned the attempt to sell his selection of old lab equipment and was giving it away...

author: electronics man
author_rank: Frequent Contributor
timestamp: May 21, 2014, 10:14:22 am
content: its lovely, I love old bits of chemical analysis gear. like the gas analysers mike tore some time ago

author: amyk
author_rank: Super Contributor
timestamp: May 21, 2014, 11:40:13 am
content: You got that from Mike?The 310J is probably worth quite a bit; around $80 according to eBay.Here's the datasheet:http://datasheet.octopart.com/310J-Intronics-datasheet-68231.pdf

author: rolycat
author_rank: Super Contributor
timestamp: May 21, 2014, 02:12:52 pm
content: Quote from: amyk on May 21, 2014, 11:40:13 amNope, another fella - Mike would probably have torn it down himselfQuoteThanks - that had not escaped my noticeI did meet Mike and he gave me the power conditioner featured in his baggage handling X-Ray teardown - a Tripp-Lite LR2000 which will find use in the lab.I also picked up an ADS 2030 PA amplifier - another freebie from the lab equipment guy:One of the input level controls is broken, but that's easily fixed.All in all it was a very good day

author: Noise Floor
author_rank: Regular Contributor
timestamp: May 25, 2014, 02:58:02 pm
content: Lovely indeed. Thanks for sharing. I know I'm getting old when I think "this is when things were built right".

author: FrankenPC
author_rank: Unknown
timestamp: May 25, 2014, 03:43:41 pm
content: Quote from: Noise Floor on May 25, 2014, 02:58:02 pmYou have to sound like a gangsta when you say this: That's discrete!