Post by thread:[BUY]: RTL logic circuts MC 660 and MC 672

In the early 70's RTL logic circuits preceded TTL. I am about to repair some old X-ray equipment fom that era, and need mentioned IC's for the purpose. I have been unable to locate these in ordinary ways. If you collect stuff the way I do, you might have some.... Near Sweden preferred, but I pay cash in most currencies. Sven in Sweden -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spam_OUTlistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

Sven in Sweden wrote: >In the early 70's RTL logic circuits preceded TTL. I am about to repair some old X-ray equipment fom that era, and need mentioned IC's for the purpose. > >I have been unable to locate these in ordinary ways. If you collect stuff the way I do, you might have some.... > Sven, if worst comes to worst, and you still must fix this equipment, you may be able to get by with cutting out the chips and soldering on some discrete NPN inverter circuits. That is really all RTL was. Somewhere I have an old textbook showing nominal resistor values. - dan -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

Milton; I have been working on some modernization efforts for the nuclear industry. They have a number of designs which used this old logic. The logic, if I recognize the numbers, are MHTL logic, which is a high threshold logic version of DTL logic made by Motorola. I would be wary of Dan's suggestion for replacing with transistor logic, Dan assumed RTL, and in reality they are a bit more than that. He meant well. The best bet is to use a comparator around 7.5V (this is fixed regardless of supply) and then deal with the logic levels. Outputs are either an active transistor output in a peculiar buffer arrangement, or a passive pullup with active pulldown. Not a clip out solder in solution. I know that the nuclear industry went absolutely to the end of the earth to find these parts, which have been out of production for probably 25 years. Wish the news was better. Sorry. Chris~ MILTON MEDICINTEKNIK KB wrote: > In the early 70's RTL logic circuits preceded TTL. I am about to repair some old X-ray equipment fom that era, and need mentioned IC's for the purpose. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

At 08:14 PM 2/19/01 +0100, you wrote: >In the early 70's RTL logic circuits preceded TTL. I am about to repair some old X-ray equipment fom that era, and need mentioned IC's for the purpose. If you want enough $$$+ worth to make it worthwhile for them, just contact a gray market dealer, there are still plenty of these old chips floating around. Be sure to specify the suffix (L or P). Best regards, =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Spehro Pefhany --"it's the network..." "The Journey is the reward" .....speffKILLspam.....interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com Contributions invited->The AVR-gcc FAQ is at: http://www.bluecollarlinux.com =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservspam_OUTTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

Chris Eddy wrote: >Milton; > >I have been working on some modernization efforts for the nuclear industry. They have a number of designs which used this old logic. The logic, if I >recognize the numbers, are MHTL logic, which is a high threshold logic version of DTL logic made by Motorola. I would be wary of Dan's suggestion for >replacing with transistor logic, Dan assumed RTL, and in reality they are a bit more than that. He meant well. The best bet is to use a comparator around >7.5V (this is fixed regardless of supply) and then deal with the logic levels. Outputs are either an active transistor output in a peculiar buffer >arrangement, or a passive pullup with active pulldown. Not a clip out solder in solution. According to the textbooks [if one can believe them], "all" of the old RTL, DTL, and HTL gates are fairly straightforward NPN circuits. So, if unable to find these gates/chips anywhere, and if fixing the equipment as opposed to trashing it is the major consideration, then it would seem that clip out solder in may be the only possible course of action. It cannot be all that difficult to try, assuming only one or a few gates are blown - either works or doesn't work. Unsolder the old chips, solder wirewrap headers into the holes, build a new gate on fiber board [kind with plated-thru holes], and solder to the WW legs. [of course, this thing probably wouldn't meet FDA approval]. - dan -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

Hmmm, so this is what will be running our nuclear power plants? <VBEG> Sean On Mon, 19 Feb 2001, Dan Michaels wrote: {Quote hidden}> According to the textbooks [if one can believe them], "all" of the > old RTL, DTL, and HTL gates are fairly straightforward NPN circuits. > > So, if unable to find these gates/chips anywhere, and if fixing > the equipment as opposed to trashing it is the major consideration, > then it would seem that clip out solder in may be the only possible > course of action. It cannot be all that difficult to try, assuming > only one or a few gates are blown - either works or doesn't work. > > Unsolder the old chips, solder wirewrap headers into the holes, build > a new gate on fiber board [kind with plated-thru holes], and solder to > the WW legs. > > [of course, this thing probably wouldn't meet FDA approval]. > > - dan > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email @spam@listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body > > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email KILLspamlistservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

At 10:40 PM 2/19/01 -0500, you wrote: >Hmmm, so this is what will be running our nuclear power plants? <VBEG> > >Sean No, this is what "has been" running our nuclear plants. [probably also the air traffic controls, IRS, B-52 bombers, 10,000 nuclear tipped missiles, most of the navy, and the SAC computers under Cheyenne Mtn - and if not here, then certainly in several other countries]. -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

Hi Dan, I wasn't clear. What I meant by "this" was little hacked discrete replacements for old ICs. IIRC, someone said that he was upgrading nuclear power plant electronics and had to deal with these old ICs by replacing them with equivalent circuits. Sean Quoting Dan Michaels <spamBeGonedanspamBeGoneORICOMTECH.COM>: > At 10:40 PM 2/19/01 -0500, you wrote: > >Hmmm, so this is what will be running our nuclear power plants? <VBEG> > > > >Sean > > > No, this is what "has been" running our nuclear plants. > > [probably also the air traffic controls, IRS, B-52 bombers, > 10,000 nuclear tipped missiles, most of the navy, and the SAC > computers under Cheyenne Mtn - and if not here, then certainly > in several other countries]. > > -- > http://www.piclist.com hint: To leave the PICList > TakeThisOuTpiclist-unsubscribe-requestEraseMEspam_OUTmitvma.mit.edu > > > -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

>>> Hmmm, so this is what will be running our nuclear >>> power plants? <VBEG> >> No, this is what "has been" running our nuclear plants. >> >> [probably also the air traffic controls, IRS, B-52 bombers, > I wasn't clear. What I meant by "this" was little > hacked discrete replacements for old ICs. IIRC, someone > said that he was upgrading nuclear power plant > electronics and had to deal with these old ICs by > replacing them with equivalent circuits. No. Original poster was asking for replacements for RTL to repair X-ray machines. Second poster said to swap discrete transistors for RTL. Third poster said he'd been working with the nuclear industry on RTL and other old logic families and warned _against_ using discretes as replacement parts. He said the nuclear industry has bought up all the old replacement parts to keep their own equipment running with the proper replacements. Lee Jones P.S. Last I heard, air traffic control system was still on IBM 9020s, circa IBM 360 level of technology. -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestEraseME.....mitvma.mit.edu

Sorry, you're right, I looked at the messages again. I stand corrected. Sean At 10:25 PM 2/19/01 -0800, you wrote: {Quote hidden}> >>> Hmmm, so this is what will be running our nuclear > >>> power plants? <VBEG> > > >> No, this is what "has been" running our nuclear plants. > >> > >> [probably also the air traffic controls, IRS, B-52 bombers, > > > I wasn't clear. What I meant by "this" was little > > hacked discrete replacements for old ICs. IIRC, someone > > said that he was upgrading nuclear power plant > > electronics and had to deal with these old ICs by > > replacing them with equivalent circuits. > >No. Original poster was asking for replacements for RTL >to repair X-ray machines. > >Second poster said to swap discrete transistors for RTL. > >Third poster said he'd been working with the nuclear industry >on RTL and other old logic families and warned _against_ using >discretes as replacement parts. He said the nuclear industry >has bought up all the old replacement parts to keep their own >equipment running with the proper replacements. > > Lee Jones > >P.S. Last I heard, air traffic control system was still > on IBM 9020s, circa IBM 360 level of technology. > >-- >http://www.piclist.com hint: To leave the PICList >EraseMEpiclist-unsubscribe-requestmitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestEraseMEEraseMEmitvma.mit.edu

Sven: I know that you wanted someplace closer than the US but... Rochester Electronics( http://www.rocelec.com/ ) specializes in parts like this. They even buy old masks to keep producing some popular (but old) parts. I did a search on their site and found the MC660L for about $11 US. They do not show a MC672. -- Rich MILTON MEDICINTEKNIK KB wrote: {Quote hidden}> > In the early 70's RTL logic circuits preceded TTL. I am about to repair some old X-ray equipment fom that era, and need mentioned IC's for the purpose. > > I have been unable to locate these in ordinary ways. If you collect stuff the way I do, you might have some.... > > Near Sweden preferred, but I pay cash in most currencies. > > Sven in Sweden > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email RemoveMElistservspam_OUTKILLspammitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservTakeThisOuTspammitvma.mit.edu with SET PICList DIGEST in the body