test-drb

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101090 discussions

by michael.99.thompson＠gmail.com

> > Date: Sun, 11 Oct 2015 18:44:54 -0500 > From: Jay Jaeger <cube1 at charter.net> > Subject: Re: PDP-12 Restoration at the RICM > > Don't forget about the other more remote possibilities: cables, > backplane, bad wrap, supply voltages at the actual card(s) for the > mis-behaving channel, etc. > > JRJ > We used different control and data cables for the TU55 and the TU56 drives and observed the same track 3 bad behavior. The backplane appears to be in good shape. My scope had a little trouble looking at 10-15mV signals in differential mode using the math functions, but we looked at the head signals going into the track 3 amplifier, and they looked reasonable. The power supply voltages at the cards are within spec. The track amplifiers are supposed to be differential, so they should be fairly immune to power supply noise. We plan to connect a lab supply to the backplane near the track cards and adjust it slightly higher than the PDP-12 power supply. That should clean up any 60Hz noise on the power. Maybe that will help? We have swapped everything else between the tracks, including the logic analyzer probe, and the issue always stays with track 3. Maybe it is a backplane wiring problem? -- Michael Thompson

10 years, 6 months

Computers in Election Vigils - take two

by paulkoning＠comcast.net

> On Oct 9, 2015, at 5:39 PM, Jecel Assumpcao Jr. <jecel at merlintec.com> wrote: > > John Robertson asked: >>> After the fiasco about the Deibold machines changing votes during the >>> Bush election of 2000, Brazil opted for them? > > To which Alexandre Souza replied: >> Yep. Welcome to the land of the stupid. > > Ok, I think we need some facts, here. Note that from the very first time > I used one of these machines to vote and noted that they typed in my > voter ID number using a little keyboard which had a cable going into the > voting "cabin" to prep the machine for my vote, my opinion of the whole > thing has be very negative. After all, I had only their word that they > were not saving my ID along with my vote - there was no hardware > limitation against it doing this. That's not the real problem. The real problem is that you had no way to be sure, no way to verify, that the machine was recording your vote and would accurately report it later. It might just as easily report numbers that someone had told it to report, not connected to any reality. How would you know? If anyone were to question this, how would you prove that the count is honest? paul

10 years, 6 months

H960 logo panel

by jnc＠mercury.lcs.mit.edu

So, I recently acquired a machine which has an unusual "digital equipment of canada, ltd." pdp11 logo panel at the top of the H960 it's in. Is there anyone who would really have a connection to a panel with that on it? (Let me hasten to add that I have nothing _against_ it, and would be happy to leave it there, but maybe someone out there is dying to have one.) If so, I'd be more than happy to swap this one for a plain pdp11 logo panel (i.e. one that says "digital equipment corporation"). Also, if anyone wants a scan of this, let me know, and I'll crank one out. Noel

10 years, 6 months

Xebec 1402A Seagate HDD controller

by dmonnens＠gmail.com

Was curious if anyone here has - or knows someone who does - a Xebec 1402A Seagate HDD controller. The drive is in an IBM 5150. Note that this MUST be the 1402A, NOT the more common 1402. There is some important historical data we are trying to recover, but the controller is nonfunctioning. Thank you for any help! -- Devin Monnens www.deserthat.com The sleep of Reason produces monsters.

10 years, 6 months

Q-bus I/O project

by dab＠froghouse.org

Wow. A pretty board indeed. Thanks for showing it off. This is also interesting to me since a friend and I have been talking about building something rather similar (and entirely different at the same time, we're just focusing on the mass storage function and using an FPGA). I'm curious about some things though, if you'd be willing. Bus drivers (along with voltage level conversion) have been a problem. You seem to be using 74LVC parts. Are they close enough? Though I also see a bunch of FETs down there. I've used OSHPark in the past for small boards but for 45 sq.in. boards they'd seem to be awfully expensive, even if using their medium run pricing. The fingers look gold plated. It could be just the ENIG finish but I also see little tails running off the bottom as if you're setup for hard gold plating. Does OSHPark have that capability? I gotta say that I'm impressed with your soldering skill as well as stamina. I was going to ask if it was machine assembled but I see in a later message that it wasn't. I was hoping for the Pick 'n' Paste machine to come along and save me from having to do all that by hand but that project seems to have faded away. I'm curious why you didn't use resistor networks instead of discrete components. I also love that your design tool put omegas on the silk screen for the resistor values. -Dave

10 years, 6 months

DEC H7140 (11/44) power supply revisions and general advice?

by jnc＠mercury.lcs.mit.edu

> From: Mattis Lind > Very nice and clear description on what is required to have relay to > activate! Indeed! Thanks, Brent, for that wonderful writeup - I'm sure I'll find it immensely useful when the time comes to work on my 11/44. I'll have to carefully save a personal copy in a file - finding it in the archives, when the time comes, won't be too easy. If only we had a Wiki we could put all this kind of stuff in... (Hint, hint!) Noel

10 years, 6 months

Panda Panel

by tmfdmike＠gmail.com

(BCC to Spare Time Gizmos and Rich A. - both of whom may have a clue!) Folks, I've finally dug out my Panda Panel and got it going - after having to deal with various strangeness in a dodgy parallel port connector, and figuring out I really DID have to be root to get it to initialize! It all works; the 'aux' CPU load segments respond appropriately, as does the Run/Disk/Tape/Network cluster. But from the moment KLH10 is started, every single segment of the main display is ON and remains ON until the host machine is powered off. Any suggestions? Is this normal behaviour? Is it just that the thing is running too fast for me to see any patterns? Does the Panda Panel care what mode the parallel port is set to in the BIOS? The fact that the other parts of the panel do the right things suggests to me that the interface etc. is basically sane... but the one photo I've ever seen of an operational panel looks quite different... http://www.sparetimegizmos.com/Hardware/images/Lingling.jpg Thanks Mike http://www.corestore.org 'No greater love hath a man than he lay down his life for his brother. Not for millions, not for glory, not for fame. For one person, in the dark, where no one will ever know or see.'

10 years, 6 months

FW: NitrOS-9 6809 L1 v3.3.0 has just been born on the Multicomp09!

by computerdoc＠sc.rr.com

Hi Guys, I wanted to give you guys an update on the latest progress on the Multicomp09. Neal Crook has just completed modifying the boot process in NitrOS-9 6809 L1 v3.3.0 and it is now booting flawlessly on the Multicomp09! I have updated my Multicomp09 with Neal's latest VHDL code and also with the latest Multi-software environment as well. I'm proud to announce that I too now have NitrOS-9 6809 L1 v3.3.0 running on my Multicomp09 as well! Whoo-Hoo! NitrOS-9 6809 L1 v3.3.0 was just born on the Multicomp09 a day or two ago so it is by far not fully tested though I'm not expecting any big hiccups at this point. Everything I've tried so far has worked fine if I recall correctly. I've been up most of the night checking it all out. :P I've changed from the default shell that comes preconfigured with L1 to Shellplus so now I have my cd command back that I'm so used to using in L2! Finally I can traverse directories with ease. I've created a /T2 device for serial port A on the Multicomp PCB. I connected putty on my laptop via a USB to serial cable and now I have a fully usable NitrOS-9 Terminal on my laptop! It's a 2 User system now. One of the next hurdles will be to get the other serial port running. There are 4 - 720KB virtual floppy drives online with the boot dsk image file on drive 0 of course and at this point the same image on the other three virtual floppy drives just to get the system up and running. With a fully functional serial port, I'm eager to see about getting Drivewire 4 up and running though 64KB of ram might be pushing it a bit. We'll see how that goes. I'm going through various commands now to make sure everything works. The device descriptor for serial port A, /T2, will need to eventually be included in the OS9Boot file as /T1. Some unneeded modules currently exist like bitbanger stuff which are not needed on the Multicomp09. Since I have shelled /T2, I can work on this at my favorite hang out at my favorite table in Mickey D's! Cool! By the way, are any of you guys on Skype? We could have a little video conference on the Multicomp! :) Take care my friends. Kip Koon computerdoc at sc.rr.com http://www.cocopedia.com/wiki/index.php/Kip_Koon

10 years, 6 months

HP & 800BPI / was Re: Tape cleaner on eBay

by marc.verdiell＠gmail.com

Thanks Brent, I had used your very helpful site before to help me figure out IO cards, but had missed this gem. Marc ================================== From: Brent Hilpert <hilpert at cs.ubc.ca> On 2015-Oct-10, at 9:59 PM, Marc Verdiell wrote: >> I had originally written it in a re-targetable cross-assembler in a > now-outdated development environment under MacOS9. >> Last year rewrote someone else's assembler (C source) - it should work in > any standard C environment. >> Was using it to re-assemble HPBASIC. >> [...] Can send you the source if you wish. > > I'll gladly take the source, that would be very helpful later on. Forgot, it's online already: http://www.cs.ubc.ca/~hilpert/e/HP21xx/software/index.html

10 years, 6 months

WTB: Compaq Portable 386

by COURYHOUSE＠aol.com

the Compaq III is quite cool there was also an add on docking thingie too to go with it. .... IBM also made a ps2 sort of one with a plasma screen on it too that was a box that closed up on it self. used to be able to find these in thrift shops often but these days you seldom see them. I got one and used it for a while until the power supply quit. For now it will have to remain a static display... for a while anyway. (schematics or maint. manual anyone!?) I even used to find Burroughs BTOS desktops in T shops but now what I need one for a display here at the museum.... none to be found! Need some to sit in the middle of these photo panel and some incredibly neat promotional items related to that computer Burroughs had put out at one time. Ed# _www.smecc.org_ (http://www.smecc.org) In a message dated 10/11/2015 7:53:11 P.M. US Mountain Standard Time, nw at retrocomputingtasmania.com writes: On Mon, Oct 12, 2015 at 12:49 PM, drlegendre . <drlegendre at gmail.com> wrote: > I believe that I do have one of these machines, and it's in good working > order as of a couple months back. You're looking for a Portable /// > correct? > > Are you in the USA? > Hi Bill, thanks for the follow-up, seeking the updated variant known as the Compaq Portable 386. https://en.wikipedia.org/wiki/Compaq_Portable_386 I'm in Australia but willing to pay the shipping to get it here.

10 years, 6 months

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