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+--- Thread: 3421A Data Acquisition Units (/thread-17651.html)
3421A Data Acquisition Units - Don Williams - 11-01-2021 03:54 PM
Bench checked 2 years ago and all functions agreed with my 5 1/2 digit Bench meter. I did not make thermocouple measurements.
Now I am just hauling them in and out of a cabinet every 3 months to top up the battery
These units are just not being used. I need the space and they need a new home.
Unit #7676
opt 201 allows GPIB or HP-IL control
44462A 10 Channel Multiplexer Assembly X 3
New Battery and cinch connector on cards
Cosmetically good. $250.00 OBO Buyer pays shipping. US only shipping
Unit #7995 - Sold
opt 201 allows GPIB or HP-IL control
44462A 10 Channel Multiplexer Assembly X 1
44465A 8 Bit Digital I/O Assembly X1
New Battery and cinch connector on cards
Cosmetically good. $250.00 OBO Buyer pays shipping. US only shipping
Unit #6471 - Parts mule
HPIL Only
44462A 10 Channel Multiplexer Assembly X 3 cards are good
Has a Cal error which I believe is in the RAM chip. No battery. No connectors for card edge.
No rear covers. $100.00 OBO Buyer pays shipping. US only shipping.
Further details and pictures provided upon request.
RE: 3421A Data Acquisition Units - Dave Frederickson - 11-01-2021 09:04 PM
(11-01-2021 03:54 PM)Don Williams Wrote: Unit #6471 - Parts mule
Has a Cal error which I believe is in the RAM chip.
The Cal error is likely caused by a depleted CAL RAM battery. Procedures for backing up the CAL RAM prior to replacing the battery and restoring the CAL RAM can be found here.
https://www.hpmuseum.org/forum/thread-8061.html
RE: 3421A Data Acquisition Units - Don Williams - 11-01-2021 10:51 PM
Been there. Done that. I replaced the backup battery 2 years ago and it still measures good. I think the RAM has developed a bad memory location. Unfortunately I no longer have the equipment I would need to validate the performance after replacing the chip. Also I am getting old and lazy.
RE: 3421A Data Acquisition Units - Duane Hess - 11-02-2021 03:52 AM
PM sent with question.
RE: 3421A Data Acquisition Units - Don Williams - 11-09-2021 05:19 PM
Unit 7995 has been sold