Obsolete ic equivalent - Page 1
Forum section: electronics / projects

author: alex89
author_rank: Contributor
timestamp: August 01, 2015, 07:00:49 pm
content: Hello there, I need a few of this ic for a repair but it seems they've become unobtainium. Is anyone aware of a direct equivalent ? Thanks :-)

author: MagicSmoker
author_rank: Super Contributor
timestamp: August 01, 2015, 08:47:44 pm
content: Well, the schematic representation certainly isn't an RS flip flop (or any other kind of flip-flop, for that matter). What is the product this IC is from, and how old is it? Just judging from the printing and weird schematic it looks to be early to mid 70's.

author: Pjotr
author_rank: Frequent Contributor
timestamp: August 01, 2015, 08:58:40 pm
content: Looks an old DTL part. A web search brings up a NTE9950 as replacement. As shown herehttp://pdf.datasheetarchive.com/datasheetsmain/Datasheets-115/DSAP001036.pdfthat part has the same pin out, although the part description doesn't seem to match.

author: Deathwish
author_rank: Unknown
timestamp: August 01, 2015, 09:08:31 pm
content: its a fairchild DTL ac coupled RS flip flop

author: alex89
author_rank: Contributor
timestamp: August 01, 2015, 09:22:12 pm
content: Yes, it's a DTL component used in an early 70's audio tape recorder. It seems a set/clear latch with a NOR on the inputs .. I'm really tempted to make a new board using a cpld but it is surely not worth the time. I've also found a Motorola datasheet describing it as a pulse triggered binary

author: Deathwish
author_rank: Unknown
timestamp: August 01, 2015, 09:27:45 pm
content: https://ia601609.us.archive.org/6/items/bitsavers_fairchilddldTTL12_375947/12.pdfno device pinouts. just tells you what it is

author: edavid
author_rank: Super Contributor
timestamp: August 01, 2015, 09:38:51 pm
content: The same part was sold by Motorola as the MC850/MC950 - they are not too hard to find:http://www.ebay.com/itm/MC850P-950PC-MOTOROLA-850N-IC-14-PIN-DIP-VINTAGE-1981-RARE-/370660761949http://www.aliexpress.com/af/mc850p.html?isAffiliate=y&site=glo&SortType=price_asc&shipCountry=us&SearchText=mc850phttp://www.utsource.net/ic-datasheet/MC850P-955359.htmlP.S. How about changing the subject line to something more specific?

author: Pjotr
author_rank: Frequent Contributor
timestamp: August 01, 2015, 09:46:28 pm
content: That NTE9950 appears to be re branded old stock:https://www.google.nl/?gws_rd=ssl#q=NTE9950

author: Deathwish
author_rank: Unknown
timestamp: August 01, 2015, 09:50:00 pm
content: http://worldpowersystems.com/archives/solid-state-datasheets/Datasheets/Fairchild-CCSL-9000-series/index.html

author: German_EE
author_rank: Super Contributor
timestamp: August 02, 2015, 12:12:10 pm
content: This would be a good part to replace with a PIC micro as some of them have pins which can be assigned as inputs or outputs.

author: MagicSmoker
author_rank: Super Contributor
timestamp: August 02, 2015, 12:49:41 pm
content: Well, at least I was right about the age of the part!DTL was pretty rugged stuff; I would do a little more investigation of the surrounding components before attempting to duplicate the functionality of this IC with modern components.Whether this is a worthwhile pursuit overall - a (presumably Ampex) tape recorder from the 1970s - I leave up to the OP.