old RTL IC's on ebay sold for $77.00 - why? - Page 1
Forum section: electronics / general

author: Jay72
author_rank: Newbie
timestamp: July 16, 2017, 02:18:45 am
content: http://www.ebay.com.au/itm/RTL-Resistor-Transistor-Logic-ICs-and-manual-Rare-Find-/222562215480?_trksid=p2047675.l2557&ssPageName=STRK%3AMEBIDX%3AIT&nma=true&si=HFHlHTRpQyS4seHEiw4v5xeBlL0%253D&orig_cvip=true&rt=ncjust wondered why these would have any worthThanks,JayPS and these toohttp://www.ebay.com.au/itm/Diode-Transistor-Logic-ICs-Rare-Find-/222562227787?hash=item33d1be164b%3Ag%3A288AAOSw-89ZU342&nma=true&si=HFHlHTRpQyS4seHEiw4v5xeBlL0%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

author: WastelandTek
author_rank: Frequent Contributor
timestamp: July 16, 2017, 02:29:54 am
content: Because you can't get them any more. There is a whole collector community around old silicon. There have even been very good counterfeits of old micros on the market.

author: Ian.M
author_rank: Super Contributor
timestamp: July 16, 2017, 02:37:59 am
content: That's only $60 USD for more than 70 chips and Don Lancaster's RTL cookbook. The RTL cookbook goes for around $15 USD, and under $0.65 a chip is pretty good for vintage N.O.S. logic.Of course if you aren't interested in early digital 'retro' stuff this isn't the item for you, but the same could be said about nearly any other specialised item on EBAY.

author: rstofer
author_rank: Super Contributor
timestamp: July 16, 2017, 02:24:25 pm
content: There are people around who started their foray into integrated circuit logic using just these devices. At this point, they could be retired with too much time on their hands and at less than $1/chip, these might be very interesting to play with.DTL would be similarly interesting. Actually, so would 74xx devices (just straight up TTL, not the new CMOS variants).

author: coppice
author_rank: Super Contributor
timestamp: July 16, 2017, 04:19:41 pm
content: Quote from: rstofer on July 16, 2017, 02:24:25 pmI started digital design with Motorola 700 series RTL when they were the latest hot items, and I had enough of them the first time around. Give me a nice big FPGA for any logic playing I want to do these days.

author: Kjelt
author_rank: Super Contributor
timestamp: July 16, 2017, 05:13:46 pm
content: I thought these things were esd sensitive to the max and the seller puts them in a standard plastick box.That is telling me he has no idea what he is doing.IMO This stuff is obsolete has little value besides repair jobs of old electronics.

author: coppice
author_rank: Super Contributor
timestamp: July 16, 2017, 05:59:31 pm
content: Quote from: Kjelt on July 16, 2017, 05:13:46 pmAlthough there was little protection added to these early ICs, they are fairly hard to damage with ESD. Bipolar devices are generally less susceptible, and the transistors are so damned big and slow in these that they damp ESD hits pretty well.

author: rstofer
author_rank: Super Contributor
timestamp: July 16, 2017, 07:17:06 pm
content: Quote from: coppice on July 16, 2017, 04:19:41 pmAbsolutely!In '69 I had just started working in the aerospace industry installing a lot of NC machinery. The Bendix Dynapath was the control system of choice (until Cincinnati Milacron came along) and these machines used resistor-transistor logic. There were multiple gates full of logic boards running at 200 kHz, I believe.So, when I saw RTL, I just had to play with it. There was more logic in a DIP than in 2 or 3 of the Bendix boards. And that was just the beginning.

author: Jay72
author_rank: Newbie
timestamp: July 17, 2017, 11:19:47 am
content: Thank You.PS I was an ATT with Telecom in '82

author: lowimpedance
author_rank: Super Contributor
timestamp: July 18, 2017, 12:14:02 am
content: Vintage electronics restoration would be the most common usage now. Just recently I had an old DMM open for some TLC and it had both RTL and TTL in the display drive sections. (my avatar pic actually).As with all obsolete tech there will be collectors and restorers.