test-drb January 2017

test-drb@ccmp.vtda.org

198 participants
283 discussions

by lists+cctalk＠loomcom.com

I'm looking for a PDF of "Introduction to DECSYSTEM-20 Assembly Language Programming" by Ralph E. Gorin. It used to be hosted on PDPPlanet (xkleten.paulallen.com), but that's been down for a while. Does anyone else have a copy they could send me? Best Wishes, -Seth -- Seth Morabito seth at loomcom.com

9 years

LGP-30 Memory Drum Update

by blstuart＠bellsouth.net

On Tue, 1/3/17, Cory Heisterkamp <coryheisterkamp at gmail.com> wrote: > What I?m wondering is if anyone is familiar with the setup/adjustment > procedure for getting the heads set correctly. There *might* be a couple of > unused tracks I can relocate heads to, but my thought is that if half a > dozen heads were already in contact, then the rest may be perilously close > as well (swelled drum?). My odds of setting 71 heads perfectly on a 50 year > old worn drum is?well?not great. A while back I read a procedure (probably in reference to the G-15). Quite frankly, it scared me a little, but I'll pass it on. The idea is to use sound. The tech would use a screwdriver as a sounding bar between the casing and his ear. Then the head was tightened down until you could just hear it start to brush. I don't remember for sure, but I'd have to think that you would then back off just enough for the brushing sound to stop. I don't recall whether the article said that this was done with the motor running or the drum was being turned by hand, but if it were my machine, I'd set the heads turning the drum slowly by hand and then check for any brushing sound when the motor comes up. Whether or not the drum is restorable, I'd still plan on building a drum simulator. That way you can get the rest of the machine up and running without stressing or depending on the drum too much. Plus if the drum does turn out to be unrestorable, you'll still be able to run the rest of the machine. As to how to approach the simulator, I would have to think a C.H.I.P. or a Pi would have plenty of horsepower, especially if you drop Linux and either run on the bare metal or as an in-kernel driver in something lighter weight. BLS

9 years

LC8-P (M8365) PDP8 printer interface schematics

by djg＠pdp8online.com

I would also be interested in schematics. I have just started looking at this board to try to use it with a ODEC/Data 100 chain printer. > Looking at the LA180 manual's description of the LC8-P interface, it > is pretty close to Centronics. I expect it is more than just a cable, > though, because there is also an OMNIBUS Centronics printer interface > board (LS8-E). That schematic is on bitsavers. > It looked to me the LA180 protocol is demand and busy high when ok to send character then the data is strobed in with data strobe pulse. Centronics is handshaked with strobe and busy so a little different. The board is simple enough that tracing it out is feasible if needed. Haven't plugged in the board yet to see how the signals behave. Still working on the printer.

9 years

Docs needed: DEC MXV11-B multi function module

by j_hoppe＠t-online.de

Hi, I've an DEC QBUS multifunction module here. Type is MXV11-B M7195. It does not boot into its ROM menu, despite I compared all the jumpers multiple time against documentation and a reference boards. So it seems something in the ROM address logic is burnt. Somebody has the FPMs schematics? I even can scan micro fiches. Thanks, Joerg

9 years

LGP-30 Memory Drum Update

by coryheisterkamp＠gmail.com

While waiting for the machine, I decided to investigate the stuck drum. This unit has 71 read/write heads plus what appears to be an inductive pickup for the system clock. Upon closer examination I discovered multiple heads in contact with the drum surface preventing rotation. And in the process of removing the mounting bars that secure the heads only then did damage become visible on a couple of tracks (scored oxide under the heads). What I?m wondering is if anyone is familiar with the setup/adjustment procedure for getting the heads set correctly. There *might* be a couple of unused tracks I can relocate heads to, but my thought is that if half a dozen heads were already in contact, then the rest may be perilously close as well (swelled drum?). My odds of setting 71 heads perfectly on a 50 year old worn drum is?well?not great. For kicks, I tried to use a piece of cheap (=thin) (0.004?) notebook paper as a feeler gage to see if I could identify the offending heads prior to support removal. This was a no-go as clearance was too tight. So, is it true these ride 0.001? off the surface? I suspect with temp and humidity changes, and given the age, I would be better off building a solid state drum emulator for the 4KW mem, but retaining the drum for the clock and possibly the 3 fast registers..if I can get those (7) heads set correctly. Any input is welcome. -C

9 years

ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

by aek＠bitsavers.org

I need some of these for making Diablo disk drive cables. Mouser/Digikey, etc. have a minimum buy of 500 (at $9 ea). Picture at http://multimedia.3m.com/mws/media/140452P/ts0005-pcb-connector.jpg Anyone see any at any surplus places? Online searches are pretty much useless because of the extremely common 40 pin male IDC plug, and my searches in the valley have come up empty.

9 years

Where are the cctech archives before November 2014 ?

by w.f.j.mueller＠retro11.de

Hi, after I remarked in November last year that the cctech archives have been `lost` Jay West responded > Walter.... > > I think you need to ask a few questions before you toss that kind of nonsense out. > > For your info - this is a hobby. It is done in spare time. The time period you > peak of - the archives have NOT been lost. Because unlike what you intone - we > do care. Those archives are safe and sound, just not in a publicly accessible > format. One of our kind list members has been working for eons to reconstruct > the publicly viewable content from them. > > I will tell him that you are going to volunteer to help him. Well, it is certainly true that the archives visible under http://www.classiccmp.org/pipermail/cctech/ only go back to November 2014. Thanks to the Internet Archive there is a full backup of the older archive sections readily available online. Simply open http://web.archive.org/web/20141025062159/http://www.classiccmp.org/piperma… and one gets all archives from October 2014 back to February 2005. There I found the postings I was looking for, and updated my links to use http://web.archive.org/. That's all. So in a wider sense nothing is lost, one has to search in the right place. With best regards, Walter

9 years

Fix for 4.3BSD-Quasijarus bootstrap on CMD SCSI controllers

by jnc＠mercury.lcs.mit.edu

> From: Josh Dersch > Thought I'd share this fix with you all just in case someone in the > future might make use of it. To help disseminate it, I uploaded the fix to the Computer History wiki: http://gunkies.org/wiki/CDU-710/M_disk_controller > From: Lars Brinkhoff > There's no central repository for fixes like these? Well, the CH wiki would be a good place, but creating new accounts on it is proving to be difficult. I'm trying to get ahold of one of the two bureacrats, to make me an admin (I've been one on Wikipedia since the Devonian), so I can create accounts for people, but so far no luck. Noel

9 years

National Semiconductor IMP mini

by vintagecomputer＠bettercomputing.net

-------- Original message -------- From: Raymond Wiker <rwiker at gmail.com> Date: 2017-01-02 11:01 PM (GMT-08:00) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: Re: National Semiconductor IMP mini I see he also has an Apple II that he wants $2000 for --- it's listed as "NON WORKING ELECTRICAL COMPONENTS FROM EXTREME AGE", and from date codes and copyright markings it appears to be far from original. In fact, the motherboard seems to be a Rev 7 RFI motherboard, and the processor is (I think) from 1985. If that one is worth $2000, my Apple IIs must be worth at least $6000 each :-) On Tue, Jan 3, 2017 at 5:24 AM, jim stephens <jwsmail at jwsss.com> wrote: > > > On 1/2/2017 8:08 PM, Josh Dersch wrote: > >> On 1/2/17 7:58 PM, Brad H wrote: >> >> >>> -------- Original message -------- >>> From: Josh Dersch <derschjo at gmail.com> >>> Date: 2017-01-02? 7:37 PM? (GMT-08:00) >>> To: "General Discussion: On-Topic and Off-Topic Posts" < >>> cctalk at classiccmp.org> >>> Subject: Re: National Semiconductor IMP mini >>> >>> >>> On 1/2/17 7:22 PM, jim stephens wrote: >>> >>>> This system looks pretty interesting, though pricey. I'm thinking it >>>> is going to be a development machine as all the switches and display >>>> would not probably have been on a production machine. >>>> >>>> I don't think National made many minicomputer format machines, in >>>> their history, someone correct me.? That might make this pretty rare >>>> on that front as well. >>>> >>>> thanks >>>> Jim >>>> >>>> Beautiful-1974-NATIONAL-SEMICONDUCTOR-COMPUTER-model-imp-16p/ >>>> http://www.ebay.com/itm/252700755919 >>>> >>>> Yeah, it's pretty cool but I don't think the seller has reasonable >>> expectations for actually selling it -- the auction started (I believe) >>> at $1500 (which may have been a reasonable price), then the seller >>> raised it to $2500, now it's at $3500 (which is fairly outrageous, in my >>> >>>> opinion).? I'm not sure what his strategy is. >>>> Bitsavers has manuals (of course...) >>>> - Josh >>>> >>> I think he figured toggle switches and lights = $$$$.? He might be >>> correct, given the obscene money I've seen laid out just for a PDP 8/e >>> faceplate. You never know a) what will motivate a collector and b) when >>> just the right collector for a given item will show up.? Every day I thank >>> my lucky stars they didn't, for whatever reason, show up for my Mark-8 >>> boards. >>> >> >> With the "No shipping cash on pickup" proviso the seller provides, I feel >> fairly certain no one's biting.? But I've been surprised before... >> >> - Josh >> > > I also passed on a PDP8/M he had, which was quite rangy then posted this > auction.? I had not come across the listing from before. > > The "Oh it must be worth a fortune", even canceling an auction 2 weeks ago > on me.? I didn't think to pay for it on auction closing, since I'd been > sniping it, or I could have really reamed the seller.? I have not gotten a > straight response from them since then. > > I would not have noted this other than what i think is a rarity. Sad that > the guy is holding it hostage from someone who could get hold of it and run > it.? I think there is one in the CHM collection from what i was told when I > checked on it before sharing here, so there is one preserved.? However > would be interesting to see one in such as Josh's or Ian's hands running. > (or many others, just share a lot with them and they are lighting blink'n > lights more than me right now). > > thanks > Jim > > I brought the RFI thing up with him. ?No response. ?There is a legit Rev 1 there too asking $3500. ?I don't find Apple IIs below Rev 0 that interesting anymore, personally. ?I think even the legit guy would struggle to get much above $1500.

9 years

was: National Semi... is Apple ][ collectability (if any)

by vintagecomputer＠bettercomputing.net

-------- Original message -------- From: "drlegendre ." <drlegendre at gmail.com> Date: 2017-01-03 8:03 PM (GMT-08:00) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: Re: was: National Semi... is Apple ][ collectability (if any) "Vent-less case" - LoL!! Add some RAM, maybe a DISC-II card and those things overheated even +with+ the vents.. that's why the Cider fan became popular, among other things. When I was in high school, we'd pop the case tops open, and run them that way. Otherwise, they'd overheat and start screwing up after the first or second class period. On Tue, Jan 3, 2017 at 10:36 AM, Brad H <vintagecomputer at bettercomputing.net > wrote: > >On 1/2/2017 11:26 PM, Brad H wrote: > > I brought the RFI thing up with him.? No response.? There is a legit Rev > 1 there too asking $3500.? I don't find Apple IIs below Rev 0 that > interesting anymore, personally.? I think even the legit guy would struggle > to get much above $1500. > >The vintagecomputer museum guy on epay is selling mounted and framed > motherboards now for $1500 (might not >work noted). > > >I guess someone would care about low ref Apple 2's but I'm not sure why > there would be any interest.? I've got one >I bought with the original > packing box, which I have picked and moved twice, which is rare for my > collecting, but I >don't know what makes any Apple 2 like that > collectible.? As in why are they collectible with low serials / part > >numbers. > > >is there any documentation as to when they were made with those numbers > that would make them significant?? >The numbers made as Raymond said would > make most of us with Apple 2's millionaires I'd think unless they have > >some other significance. > > >just curious. > >thanks > >Jim > > When I got into collecting an original Apple II was as rare as hen's teeth > on ebay, etc.? Those got huge bucks, regardless of rev.? Then sellers > caught on and stuff started coming out of closets, basements, estate > sales.? I actually track Apple II sales and prices have massively declined > since 15 years ago.? I mean, there's 60000+ out there theoretically, and > II+ shared the same components and production lines for a time.? Only diff > was the ROMs.? Now Rev 0 is where it's at, especially a rare ventless > case.? Oh, and late SNs in the 70000 range for some reason still get > $700-800.? I don't know why. > > The one thing I can tell you is, if an 'expert' tells you something about > original II production, there's a good chance they are wrong.? Some > authoritative sources claimed no Rev 02 boards went into public hands, for > example, but I have one in my SN 16000s machine.? Some would claim that > can't be original, but it is.. the date code on it is the same as the > keyboard and case, all right in the range of other 16000 series machines, > which on either side of mine have Rev 03.? Apple didn't use the same rev > consistently.. sometimes they just grabbed from the pile.? It's kind of a > dogs breakfast after Rev 0. > > My Rev 02 operates no differently, other than Integer BASIC, than my RFI > II+.? More and more I'm not finding IIs to be all that amazing or worth > fighting over.? A Rev 0, just owing to the few truly unique design > features, is the only one I might want now. > > > > Yeah. ?We were on to IIes when I was in grade school and then Commodores and PCs after that.. original IIs and II+ were long gone. ?I have four units and never have any issue but come to think of it I do tend to run them case top off. ?I imagine other users might have run them with the monitor (another massive heat source) sitting right on top. I think the ventless cases also were made of a weaker plastic that melted and warped just from the heat of the innards. ?The few examples I've seen are almost invariably somewhat concave. ?

9 years

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test-drb January 2017