Re: early (pre-1971) edge-triggered D flip-flop ICs

On Wed, Jul 19, 2017 at 6:10 PM, Eric Smith via cctalk wrote: > I'm interested in the history of the logic design for the edge-triggered D > flip-flop, as used in the SN7474... > > Does anyone know what year the SN7474 was introduced, or have an early > datasheet for it

Re: HP 300-series boot rom archive?

On 7/19/2017 10:43 AM, Peter Brown via cctalk wrote: If yours is dead, a bad power supply is the most likely issue. The same power supply was used in the 9000/340 but the 340's service manual doesn’t tell you much about the internals of the supply. The 345 service manual tells you more but

Re: early (pre-1971) edge-triggered D flip-flop ICs

Thanks for all the info, Brent! The MECL II MC1022 is an edge-triggered D flip-flop using master-slave design. I'll have to look up the others you mentioned, especially the National DM8510 and Sprague NE8828. I've previously overlooked the MC778 mW RTL D flip-flop, which also uses a variant of

Re: Removing Pitting and Rust From an Enclosure

On 07/19/2017 07:13 PM, Fred Cisin via cctalk wrote: > In most places other than the south and Chicago, Coke and Pepsi are what > is used. I don't think that SNL (Saturday Night Live) ever did a "No > Coke; RC" skit. There's also some stuff called "Naval Jelly"

Re: Removing Pitting and Rust From an Enclosure

On Wed, 19 Jul 2017, drlegendre . via cctalk wrote: Chuck is right, but pits can also be filled.. JB Weld is one suggestion. It can be sanded perfectly smooth & painted over. You can also try using some auto-body spot filler, though I don't know how tough that is. tough enough that it is

Re: Removing Pitting and Rust From an Enclosure

Chuck is right, but pits can also be filled.. JB Weld is one suggestion. It can be sanded perfectly smooth & painted over. You can also try using some auto-body spot filler, though I don't know how tough that is. If the rust pits are deep, you can use muriatic acid to clean the rust out of the

Re: early (pre-1971) edge-triggered D flip-flop ICs

On 7/19/17 5:36 PM, Brent Hilpert via cctalk wrote: > I also have the 65 TI catalog, which introduces the 5400 / future-7400 > series, but the family is only half-a-dozen packages of gates and the 5470 FF > at that point. > I started scanning Allied Electronics catalogs since they give

Re: early (pre-1971) edge-triggered D flip-flop ICs

On 7/19/17 4:40 PM, Brent Hilpert via cctalk wrote: > There are near-type cross-refs in the 69 book to the National DM8510, Sprague > NE8828, Sprague USN7474, and Signetics N7474. > > I can take and email you photos of the applicable pages if you like. > Don't have a web site up right now to

Re: early (pre-1971) edge-triggered D flip-flop ICs

On 2017-Jul-19, at 3:10 PM, Eric Smith via cctalk wrote: > I'm interested in the history of the logic design for the edge-triggered D > flip-flop, as used in the SN7474. The design is composed of three set-reset > latches (six NAND gates total) per flip-flop. > > Does anyone know what year the

Re: Removing Pitting and Rust From an Enclosure

On 07/19/2017 03:13 PM, Fred Cisin via cctalk wrote: > To get rid of the pitting, you would have to grind, brush, or mill > down to below the depths of the pits. Or fill them in (bondo?) and > paint over. Maybe paint it like an 026 punch? Crackle-coat paint looks very nice. Removing pits by

Re: early (pre-1971) edge-triggered D flip-flop ICs

On 07/19/2017 03:10 PM, Eric Smith via cctalk wrote: > I'm interested in the history of the logic design for the edge-triggered D > flip-flop, as used in the SN7474. The design is composed of three set-reset > latches (six NAND gates total) per flip-flop. > > Does anyone know what year the SN7474

Re: Diskette size (was: Repurposed Art (ahem...)

"That is why they switched from 8 foot to 5.25 foot floppies." LOL On Wed, Jul 19, 2017 at 12:15 PM Fred Cisin via cctalk < cctalk@classiccmp.org> wrote: > >> Did any one ever use keypunch to tape or 8' floppy? > On Wed, 19 Jul 2017, Mike Stein via cctalk wrote: > > Those 8' floppies were a

RE: Removing Pitting and Rust From an Enclosure

> You can't remove pitting. You mean remove the dark oxide? On Wed, 19 Jul 2017, Rob Jarratt via cctalk wrote: Well yes, I suppose so, and anything that can be done to make the result look a bit better after removing the dark oxide. maybe steel wool? or try a wire brush that is softer than

early (pre-1971) edge-triggered D flip-flop ICs

I'm interested in the history of the logic design for the edge-triggered D flip-flop, as used in the SN7474. The design is composed of three set-reset latches (six NAND gates total) per flip-flop. Does anyone know what year the SN7474 was introduced, or have an early datasheet for it (prior to

RE: Removing Pitting and Rust From an Enclosure

Well yes, I suppose so, and anything that can be done to make the result look a bit better after removing the dark oxide. Regards Rob From: dwight [mailto:dkel...@hotmail.com] Sent: 19 July 2017 22:16 To: r...@jarratt.me.uk; Rob Jarratt ; General

Re: Removing Pitting and Rust From an Enclosure

You can't remove pitting. You mean remove the dark oxide? Dwight From: cctalk on behalf of Rob Jarratt via cctalk Sent: Wednesday, July 19, 2017 12:52:44 PM To: General Discussion: On-Topic and Off-Topic

Speaking of detached keyboards

Among the things I found when I was unpacking into my new house was a keyboard (minus a couple arrow keys) from a Model 40 Teletype. I apparently paid $5 for it from the Island of Misfit Toys at the back of Gateway Electronics in STL. Anyway. As keyboards go, it is super-duper clicky. It has a

Removing Pitting and Rust From an Enclosure

The TURBOchannel extender I got has a bit of rust and quite a lot of dark pitting on the steel surfaces. I am not sure what the finish is, whether it is anodized or galvanized. In any case, does anyone have recommendations for how to remove the unsightly pitting? Bear in mind that I am in the UK,

Re: HP 300-series boot rom archive?

> If yours is dead, a bad power supply is the most likely issue. The same > power supply was used in the 9000/340 but the 340's service manual doesn’t > tell you much about the internals of the supply. The 345 service manual > tells you more but the supply for that box is a different model. I

Re: PDP11 and Simh Floating point

On 07/19/2017 09:49 AM, Paul Koning via cctalk wrote: > An example where you'd be way off is the CDC 6000 series, which has > integer mantissas and doesn't necessarily normalize the answers. So > even apart from the encoding conversion, the answer won't match. Or > the Electrologica X8, which

Re: PDP11 and Simh Floating point

On 7/18/2017 11:38 AM, Paul Koning via cctalk wrote: On Jul 18, 2017, at 11:04 AM, Douglas Taylor via cctalk wrote: How does SIMH perform floating point operations for the PDP-11 simulation? If I run a numerical computation on real PDP-11 hardware and also on Simh how

Re: iMac ethernet connection quit - help?

All, update - sorry for long delay, life happens. I did execute the firmware update procedure from the URL listed up-thread. It went seamlessly (I held the programmer’s button in with a deer antler from the greenbelt behind my house - is that a unique way to update an iMac?)

Diskette size (was: Repurposed Art (ahem...)

Did any one ever use keypunch to tape or 8' floppy? On Wed, 19 Jul 2017, Mike Stein via cctalk wrote: Those 8' floppies were a PITA to handle and store, but they sure held a lot of data... ;-P That is why they switched from 8 foot to 5.25 foot floppies. Punchcard size is reputed to have

Re: Diehl Combitron

This is a truly wonderful accomplishment, as well as a great remembrance of a true genius in early electronic calculator design, not to mention computer design.   Stan Frankel isn't all that well known, but those that do know of him hold him in high regard. He was a master of minimizing

Re: Repurposed Art (ahem...)

- Original Message - From: "ben via cctalk" To: Sent: Tuesday, July 18, 2017 10:45 PM Subject: Re: Repurposed Art (ahem...) > On 7/18/2017 2:11 PM, Fred Cisin via cctalk wrote: >> On Tue, 18 Jul 2017, Ed via cctalk wrote: >>> at least they

RE: Repurposed Art (ahem...)

From: cctalk [cctalk-boun...@classiccmp.org] on behalf of ben via cctalk [cctalk@classiccmp.org] Sent: Tuesday, July 18, 2017 10:45 PM To: cctalk@classiccmp.org Subject: Re: Repurposed Art (ahem...) On 7/18/2017 2:11 PM, Fred Cisin via cctalk wrote: > On

Diehl Combitron

Hi, I want to share the latest result of a bachelor thesis in our museum. We are now able to program and load arbitrary machine programs and run them on the Combitron. As a proof-of-concept, the student wrote an hommage to Stanley Frankel, the designer of the CPU, by writing a boot tape that

Re: Repurposed Art (ahem...)

On 18.07.2017 16:27, Cory Heisterkamp via cctalk wrote: On Tue, Jul 18, 2017 at 9:14 AM, Philipp Hachtmann via cctalk < From a seller's point of view, they've got a keypunch that's worth less painted than if it were original, unless you're an art fanatic with lots of space to display such

Re: HP 300-series boot rom archive?

On Jul 18, 2017, at 8:38 AM, Al Kossow via cctech wrote: > When MAME started supporting the 68K 9000s, I made an effort to go through > all of my machines > and dump the firmware. I didn't have a 375, which is why it isn't there. It > would be nice if > some other collectors (Bear?) would dump

Re: Repurposed Art (ahem...)

Pete - Sad about the McGraw-Hill Electronics Which issues are you missing!? Ed# _www.smecc.org_ (http://www.smecc.org) In a message dated 7/18/2017 9:43:25 P.M. US Mountain Standard Time, cctalk@classiccmp.org writes: The paint job doesn't bother me much. I had a working 26 that I