test-drb April 2016

test-drb@ccmp.vtda.org

203 participants
299 discussions

by rich.cini＠verizon.net

All ? I?m helping a buddy of mine restore an original XT and original AT and I?m looking for original boot disks for them. I have the AT Diagnostics disk but the other disks I have seem to be bad. Does anyone have images that they could send me or point me to an archive of original disks? Thanks! Rich -- Rich Cini http://www.classiccmp.org/cini http://www.classiccmp.org/altair32

8 years, 8 months

websites on the classiccmp server

by jwest＠classiccmp.org

8 years, 8 months

DEC LPS11 Laboratory Peripheral System for PDP-11

by echristopherson＠gmail.com

I saw a DEC LPS11 Laboratory Peripheral System for PDP-11 somewhere and was thinking of getting it just because of the Digital nameplate, but I was too broke. Now I see that an ebay listing[1] of it has the ambitious Buy It Now price of $1600 -- but that's with cabling and a book of schematics, and they've tested it out at least a bit; and it has analog in and out, and several specific boards in it. The one I found, on the other hand, is untested and doesn't have any external goodies; it does seem to be populated with boards, but I don't know what they are. It also seems to be lacking any analog in or out (unless the "DISPLAY" port is an analog out). I'm wondering if there would be a demand for this item. If so, I may have to send someone to pick it up for me when the place is open next. [1]: http://www.ebay.com/itm/DEC-LPS11-Laboratory-Peripheral-System-for-PDP-11-A… -- Eric Christopherson

8 years, 8 months

H-11 Updates

by rich.cini＠verizon.net

All ? It?s been a productive two weeks with my pseudo-DEC Heath H-11. I got myself an Emulex UC07 SCSI card and a SCSI2SD SCSI drive emulator. After a week of noodling around with why the on-board diagnostics wouldn?t load (stupid LTC jumper) I was able to confirm that the board and SCSI2SD setup worked. Tonight I built an RD54 image of RT-11 v5.7 using SIMH and dd?ed it to the card and now I have RT-11 5.7 running over SCSI. Yea! Rich -- Rich Cini http://www.classiccmp.org/cini http://www.classiccmp.org/altair32

8 years, 8 months

Voltage regulator with alternate voltage source...

by hilpert＠cs.ubc.ca

On 2016-Apr-08, at 11:58 AM, Bill Sudbrink wrote: > I don't know why I bothering to be coy about it... > > My unit here: > > http://wsudbrink.dyndns.org:8080/images/cyclops-latest/P4060005.JPG > http://wsudbrink.dyndns.org:8080/images/cyclops-latest/P4060006.JPG > > Actually, I'm further along than that, but I > don't have more recent photos. > > Original unit here: > > http://www.swtpc.com/mholley/PopularElectronics/Feb1975/PE_Feb_1975_pg30.jpg > > Schematic here: > > http://www.swtpc.com/mholley/PopularElectronics/Feb1975/PE_Feb_1975_pg28.jpg Well that's neat. I assembled the Cromemco kit version of the Cyclops ( https://en.wikipedia.org/wiki/Cromemco_Cyclops ) ca. 1976 for a friend with an IMSAI, and built the companion adapter to provide display on an oscilloscope, but I don't know that it was ever made to work. (The kit version presented an interface for a computer rather than the scope drive of the magazine article. Hopefully you're more successful with your unit. (I think you'll find the MC7805 there is indeed plastic not ceramic. Moto produced various power transistors and regulators in those packages (case 90 in Moto parlance) as well as a smaller version from the same plastic material) A 9V wall wart would probably do for the power supply, or remove the regulator and use a modern 5V switching wall wart (not that I wish to promote wall warts, but if they're on hand . . )

8 years, 8 months

ADM 3a with no horizontal scan

by lists＠loomcom.com

Hey folks, I've been on a tear trying to resurrect old projects here, and next on the list is an ADM 3a. This particular 3a has no horizontal scan. None at all. I just get a vertical line down the center of the screen. First thing I checked was the horizontal deflector on the yoke, which seems secure. Before I go diving into the schematics, I figured I'd ask here: Is this a common failure mode? Has anyone else experienced no horizontal scan on a 3a? Any tips on where to look first? -Seth -- Seth Morabito seth at loomcom.com

8 years, 8 months

Stuff searching for new home around Duesseldorf, germany

by jnc＠mercury.lcs.mit.edu

> From: Peter Koch > rumours are that kids do place stuff like this into their parents > basement :-) I've even heard rumours of parents placing stuff like this into their kids basements! (I certainly have some PDP-11's in my daughter's old bedroom! :-) Noel

8 years, 8 months

A tale of a chip and a socket

by jnc＠mercury.lcs.mit.edu

> From: Torfinn Ingolfsen > Most likely a bad solder joint. That was my first thought, and so I carefully inspected all the pins, but they all looked good to me. But I suppose it might have been something that wasn't visually obvious. Noel

8 years, 8 months

A tale of a chip and a socket

by jnc＠mercury.lcs.mit.edu

So I just had the incredibly amusing experience of managing to repair an -11/04 CPU by un-soldering a chip, putting in a socket, and putting _the same chip_ back in that socket! Before you go 'WTF?!?!', let me explain what happened. The CPU wouldn't run, and in poking around, I stumbled on the cause: all the registers would not 'take' 1's in the 0360 bits. Hmm, 4 contiguous bits - sounds like it might be a bad register file chip. But before I pulled it, I wanted to make sure it wasn't some other part of the data path - Mux, ALU, etc. So I put a DIP clip on the chip, whipped up a 3-instruction 'scope loop that would exercise it, and... while I was looking at it, the problem went away! WTF? So I pull the clip - and the problem comes back. Repeat. Clearly there's a bad connection in the chip, and the pressure of the clip is 'fixing' it. So I pull the chip, put in a socket (I always use sockets on repairs, I'm paranoid I'll overheat the parts - I don't mind living with an potential eventual bad contact from corrosion), and figure what the heck, let me see if fiddling with it fixed the bad connection - and sure enough, it now seems to work! And if it eventually fails, no problem - it's in a socket, I know where to go if the machine stops working, those P3101A's are rare and expensive, etc! :-) Noel

8 years, 8 months

Stuff searching for new home around Duesseldorf, germany

by cctalk.pkoch＠dfgh.net

Hi all, we have been using two Sun 6800 (each fully equipped with 96GB of RAM and 24 Sparc III processors 1.2GHz) for many years. Now they are retired and must leave our machine room to make place for newer machines. Anybody out there willing to give them a new home? They are very good in transforming electric energy into heat. And by activating only some of the processor boards you can regulate the heat flow. Your wife will love to stand behind it and use it as a whole-body blow-dryer. Take one for free and you will get another one for no additional costs. While rearranging our machine room, we found lots of other stuff that must go away too. Here's the current list: - Sun E250 - Sun A5200, 2xA5100, D1000 with lots of disks - Sun E450, 2x, one is still needed for a couple of months - Sun L1000, 3x, one is still needed for a couple of months - Sun 6800, 2 fully equipped and a third one for spare parts - Sun 880 with 12 disks - Sun 480 2x, with spare processor boards - Sun L11000 tape library (aka ATL P3000) with 6 drives and lots of tapes Be warned: You need a truck with lift to transport a Sun 6800. It's 191x130x61cm and weights approx 500kg. Same thing with the tape library: 192x72x145cm, approx. 600kg. On the other hand rumours are that kids do place stuff like this into their parents basement :-) I took some pictures and uploaded then to http://flic.kr/s/aHskuakSMT Peter

8 years, 8 months

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test-drb April 2016