Identifying an old BI Technologies IC? - Page 1
Forum section: electronics / projects

author: TheAdmiralty
author_rank: Contributor
timestamp: April 30, 2023, 05:01:35 pm
content: Here's one maybe someone around here was familiar with back in the day. I've just come into possession of 14 old ICs that I can't find any information on whatsoever. Images of the box attached.Components are marked "BI 7555CH." Package is a ceramic DIP-32 with a hermetically sealed cover. No markings on the underside except for a lot number.I guess BI Tech is now TT Electronics, and my original thought was that these are just some customer-specified precision resistor network, but all the markings are very clear that "WARNING CMOS DEVICES ENCLOSED." I can't find any drawings either online or from our company that threw these out, and there's no record of them being used anywhere.I'm not too hopeful on this one, but does this ring any bells with anyone around here?---Some context, our company is moving their office and there are thousands of tubes/reels/etc of obsolete components and equipment being thrown out while they do the first cleanout in fifty years. I've been grabbing anything that looks even remotely useful - Keithley 8505A meter, Tek TM5006 GPIB mainframe with some function generators, a metric asston of interesting obsolete ICs, etc. Bunch of Intel 8008, 8080, early Analog Devices ADCs/DACs, bunch of ceramic MC6802s... and not just one or two, there were tens of new tubes of these things. I might make a thread to show off the haul lol. These were in a cabinet that's been locked for the last two decades with a lot of other precision converters and similar, so I have reason to believe they were at least somewhat valuable otherwise I'd just have let them go to the e-waste crate.

author: DavidAlfa
author_rank: Super Contributor
timestamp: April 30, 2023, 06:12:37 pm
content: https://datasheet4u.com/mobile/489147/7555.htmlDon't trash then, try listing them on eBay!

author: TheAdmiralty
author_rank: Contributor
timestamp: April 30, 2023, 06:36:56 pm
content: Huh. Welp, I apparently looked right at that link and passed over it, because all I thought I saw on datasheet4u was a timer by the same name.Yup, nothing's getting trashed - don't have any plans for any of it yet, might sell some of the more expensive analog parts, haven't decided yet.Only problem is that while I tried to only take the tubes of things that looked new/complete, a lot of the old DIP parts have markings/labels on them that mean they were probably socket pulls from dead boards, and so I don't really know the state of those ones.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: May 01, 2023, 12:19:58 am
content: Yeah, if it looks like the chip has been used, then they are likely to be bad parts swapped out. But think of it as hours of fun testing them.

author: TheAdmiralty
author_rank: Contributor
timestamp: May 02, 2023, 03:11:04 am
content: Oldest couple of parts that I've saved yet. The Beckman 7555C is stamped "75 B" underneath but I don't think that's a date code since I see them marked "30 J" elsewhere.

author: srb1954
author_rank: Super Contributor
timestamp: May 02, 2023, 08:12:24 am
content: Quote from: TheAdmiralty on April 30, 2023, 05:01:35 pmPop the top of one of the chips to see what is inside. Judging by the case style I would guess that it is probably some form of hybrid circuit rather that just a monolithic IC.