test-drb April 2011

test-drb@ccmp.vtda.org

184 participants
276 discussions

by ethan.dicks＠gmail.com

On Tue, Apr 26, 2011 at 7:34 PM, Michael Thompson <michael.99.thompson at gmail.com> wrote: > We (RICM) have an 8/I with 5x TU55 drives, a pair of bare 8/L, and a > very functional 8/S that now runs FOCAL. Did you have to do any work on that -8/S? I have one that needs a lot of replacement bulbs and some sleuthing in the "lock" circuit (the switch is fine, but the machine behaves as if it's always in "lock" mode). I've done lots of work on M-series machines like the -8/L and -8/i (it's where I got my start with 12 bits), but virtually no debugging of the older logic. I built a simple M-series FLIP-CHIP tester with a DEC backplane socket and an 6821 PIA, but it was straightforward to abstract different arrangements of inputs and outputs for different modules. I haven't done the homework to see how many types of R/S-series modules are used in a Straight-8 or -8/S, so I'm not even sure how difficult it would be to make a comparable logic tester. I'd like to automate the testing to the point where I could at least plug in a suspect module and either flip some switches or type some commands to exercise the inputs and monitor the outputs - yes, one can debug pre-TTL machines with a lot of clip leads and an oscilloscope, but I'd like to abstract that one level to see what boards need detailed attention. Has anyone ever considered building an automated or semi-automated R/S-Series module tester? Did it get further than musings and drawings? -ethan

13 years, 7 months

Fwd: [alt.folklore.compute...] PDP11GUI: Home page has moved

by legalize＠xmission.com

This message has been forwarded from Usenet. To reply to the original author, use the email address from the forwarded message. Date: Sun, 17 Apr 2011 11:35:24 +0200 Groups: alt.folklore.computers,de.alt.folklore.computer,alt.sys.pdp11 From: =?ISO-8859-15?Q?J=F6rg_Hoppe?= <j_hoppe at t-online.de> Org: albasani.net Subject: PDP11GUI: Home page has moved Id: <ioec8s$gro$1 at news.albasani.net> ======== Home page and online doc of PDP11GUI have moved to www.retrocmp.com/tools/pdp11gui The download is an attachement now. The old page is still alive, but will disappear without further notice. Enjoy! Joerg Hoppe

13 years, 7 months

IBM 9000 / 9221 Mini Main Frame on eBay

by wmaddox＠pacbell.net

Any fans of 90's-vintage IBM gear to save this machine from the gold scrappers? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170628677445

13 years, 7 months

H7140 PDP11 PSU

by ard＠p850ug1.demon.co.uk

> > I will add some diagnostic wires to the board as you suggest, I don't > remember a lot about TTL chips, is there a convention about which are the > power pins? > > In the meantime someone else told me that the click I would hear when > connecting to the mains (before switching it on with the key) was some kind > of relay. I don't hear that anymore, would that help to isolate the problem > at all? OK, I am looking at the schemaitcs... I will take the referenes from this manual on bitsavers, since I guess we all have access to it. http://www.bitsavers.org/pdf/dec/pdp11/1124/MP01018_1124schem_Aug80.pdf This is a complex PSU, and it is not obvious at first sight what is going on, but I will try... I will put page references (to that PDF) in brackets. The relay is K1 (p70). It shorts out a soft-start resistor in series with the input to the mains bridge rectifier. This produces 350V across C1/C2 in series. Now much of the PSU circuitry runs off a little SMPSU. The chopper transformer is T1 (p82). It provides about 12V across C3 (p82). Now we need to look at the 'Bias and Interface Board'. The relay is driven by E4 (p86). It's essentially a 'mains OK' circuit, the relay is energised when the votlage across the mains smoothing capacitors is high enough to trigger E3a. E3a is on the mains side of the isolation barrier, of course. But the relay driver (E4) is powered from a signal called '+5V'. This is not the +5V that you're expecting. It comes from the 7805 regulator E1 (p87). The input to that comes from that little SMPSU I've been talking about. This is isolated >from the mains. The control circuitry for that is on page 88. Be warned that this circuitry is NOT isolated from the mains. It's a relatively conventional SMPSU with the control circuitry powered straight from the mains. Q1 (p88) is the chopper transistor. So, if everything's working right, this SMPSU starts up when you apply mains to the machine, the 'mains OK' circuit triggers and the relay pulls in. I would start by checking that '5V' supply, remember it's not the one to the backplane. Check it at the output of E1, for example. If it's missing, as I think it will be, you need to sort out the SMPSU I've been talking about. But let's find out if you need to do that. -tony Regards Rob -------------------------------------------------------------------- mail2web.com ? What can On Demand Business Solutions do for you? http://link.mail2web.com/Business/SharePoint

13 years, 7 months

command line "museum"

by geneb＠deltasoft.com

Check it out: http://telehack.com @ basic Darthmouth DTSS TeleBASIC (c) 1964,1966,1969,1970,1971,1979 > Blows my mind. :) g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.simpits.org/geneb - The Me-109F/X Project ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://www.scarletdme.org - Get it _today_! Political correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

13 years, 7 months

Have: Control Data 8528 digital communications terminal reference manual

by alexeyt＠freeshell.org

I've found a control Data 8528 Digital Communications Terminal Reference Manual at a book sale for $1 :-) It's letter size, soft cover, about 100 pages, contains a number of schematics and is copyrighted in 1964. The 8528 appears to be a 12-bit modem that can be used over coax, microwave or leased telephone links at up to 10^5 words/sec. It comes with a telephone handset in case you want to talk to the person on the other end :-) It can be yours for the cost of media mail shipping from 27606. I see that CHM has one (but no scans posted), but I don't see a copy on bitsavers, so Al gets dibs if he wants it. I can also scan it free for anyone who's interested. Alexey

13 years, 7 months

Tektronix photos updated

by vintagecoder＠aol.com

Richard <legalize at xmission.com> wrote: >> I wonder if the MCAUTO label on your keyboard means McDonnell Douglas >> Automation. > Yes, I believe it is. We discussed this on the length some time ago when > I first got this terminal and that was aour conclusion from that > discussion. I haven't done any independent research on it yet, but it > seems reasonable to me. Sorry about that. I was either not a list member yet or I missed the discussion. >> I personally would love to have a 4051, does anybody remember those? > I have one 4051 that needs some keycaps and some electrical repair before > its functional. Also, I would like to create some sort of replacement > for the cartridge tape drive for loading software from disk image files. > That's a hardware project that's on my list. Yes, the cartridge tapes were really nice on those units. Somewhere I've got a few tapes with some old code on them. Good luck with all that! Really nice unit that 4051.

13 years, 7 months

Free (Seattle) - M4 Data 9-track drive

by derschjo＠mail.msu.edu

I've got what I'm fairly sure is some model of M4-Data 9-track drive in a "desktop" enclosure, relabeled as an "Interface Data, Inc." drive. It's similar, but not identical, to the 9914 for which there is documentation on Bitsavers. It appears to do 1600 and 3200 BPI (not sure what encodings.) It has a Differential SCSI interface option, along with a Pertec interface. It's labeled on the back as "Model No. 9946." I have some pictures I took when I first got it (it hasn't changed much since then) at: http://yahozna.dyndns.org/scratch/9-track/ The tape transport seems to be working fine (it loads and unloads, moves to BOT and rewinds just as I'd expect. The auto-loading procedure on these drives always seems magical to me...) but there's something wrong with the digital side of things. I've made a few attempts over the past couple of years to use the Pertec interface (with the Diff SCSI interface removed) but all reads result in parity errors. It may just be a configuration issue -- there are tons of configurable settings via the front panel -- but I lack the documentation to know what they are (they are not the same as the 9914's as far as I can tell) or to do any other testing. Picked this up almost three years ago (time flies!) and it's just been taking up space. Time to get it out of here. Anyone want it? It's free! Pickup only in the Seattle area. And if anyone in the Seattle area has a Pertec-interface 9-track drive they want to part with, let me know :). - Josh

13 years, 7 months

H7140 PDP11 PSU

by ard＠p850ug1.demon.co.uk

> I have extracted the leftmost board, which is a 5413605, according to > printset that is a "bias and interface" board. Looking at where it is > mounted in the PSU, it *appears* to be connected to the fan spade > connectors, so would be involved in powering the fans (the motherboard > printset would seem to confirm that). There is a 74LS00 chip on it to which > I will attach wires to Vcc and Ground so I can test if for power. I followed > the Vcc track on the back of the board and it does not appear to go to the > boards "backplane" connectors. I tried to read the printset to see which > pin(s) on the connector the power comes in on but I don't understand the > conventions about which pin is pin 1 on the connectors, so I can't at the > moment add wires for that. I will go ahead and add wires to the 74LS00 in > the meantime. See my other messages :-) The 5V line you are interested in comes from a 7805 regulator (TO220 package, looks like a power transistor) on that PCB. I suspect it does power the 74LS00 you mention too... The ground for this supply is the same as the machine's logic ground (this will not be the case if we have to sort out the control circuitry of that little SMPSU). Yes, the fan full-H driver circuit is on this PCB, so it's not suprising it's connected to the fan terminals. -tony -------------------------------------------------------------------- mail2web.com - Microsoft? Exchange solutions from a leading provider - http://link.mail2web.com/Business/Exchange

13 years, 7 months

H7140 PDP11 PSU

by ard＠p850ug1.demon.co.uk

> I will add some diagnostic wires to the board as you suggest, I don't > remember a lot about TTL chips, is there a convention about which are the > power pins? Conventionally the corner pins (on a 14 pin device, for example, pin 14 is +5V, pin 7 is ground). But there are exceptions. A TTL databook, or a way of reading the data sheets on-line is almost essential :-) The power distribution arrangements are shown on page 11 of that pdf manual I mentioned : http://www.bitsavers.org/pdf/dec/pdp11/1124/MP01018_1124schem_Aug80.pdf Look at the '11/24 Power Distribution BD' part of the schematic. There's a +5V line coming from the PSU and ending up on pins 1 and 4 of the backplane sockets and a separate +5VB going to pin 12 of those sockets. Of course you need to fix the PSU before you can start sorting that out. -tony -------------------------------------------------------------------- mail2web LIVE ? Free email based on Microsoft? Exchange technology - http://link.mail2web.com/LIVE

13 years, 7 months

← Newer
1
2
3
4
5
6
7
8
...
28
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb April 2011