test-drb June 2016

test-drb@ccmp.vtda.org

196 participants
290 discussions

by jnc＠mercury.lcs.mit.edu

> I'm puzzled as to how one could drive both interlaced and > non-interlaced monitors off the same video signal - wouldn't the > interlaced one need a video signal which has 'odd lines, then a > vertical retrace, then even lines, then a vertical retrace'? So to sort of answer my own question, interlaced and non-interlaced video signals are indeed different. It turn out that 1024x768 was defined by IBM as XGA, and it was originally an interlaced format - although a non- interlaced version was done later. So my laptop quite possibly really is producing interlaced video... Although how a monitor is supposed to tell whether a signal is interlaced, or non-interlaced, is not clear - there's certainly no pin on the VGA connector which says so! :-) > Anyway, so which one is the one which is the number to look at when > considering if the refresh rate is so high it might be dangerous to an > old CRT monitor? > E.g. my HP M50 manual says "Setting the screen resolution/refresh rate > combination higher than 1024x768 at 60 Hz can damage the display." Since the monitor I'm using is called an "Ultra VGA 1024", I'm going to assume it can handle 1042x768, and just stop worrying about it... If it melts down the monitor, it melts down the monitor! :-) > From: Jochen Kunz > Sounds like an interlaced video mode. No surprise that the LCD can't do > this. Yes, as soon as I realized it probably really was interlaced video, it became obvious why none of my LCD monitors would display it. Noel

9 years

Any extra DEC monitors in Europe?

by useddec＠gmail.com

I have a friend looking for 2 DEC VRC21-KA monitors in Europe. I have one here, but will pack it only as a last resort. If you have one of two you want to sell or trade, please let me know off list. Also where you are located. Thanks, Paul

9 years

Monitor refresh rate query

by jnc＠mercury.lcs.mit.edu

So I'm using an old (very old! :-) laptop for a console for some of my computers. The built-in screen on it is this miserable 800x600 thing (I said it was _old_ :-), so I'm trying to hook up an old 15" display (of which I have tons) and run it at 1024x768 at least (the highest resolution the old display hardware in the laptop will support). However... The first couple of LCD's I plugged in, they worked fine, but when I went to change from 800x600 to 1024x768, I got error messages about 'can't handle that display format' (or words to that effect). Nothing about what parameter was out of bounds, alas. Finally I found one that _did_ give me the numbers, and it said the retrace was 35.6 Khz / 44 Hz. OK, looking at some specs, it makes sense those LCD monitors didn't work - 44 Hz vertical retrace (which I gather is the same as the refresh rate, in things like 1024x768/60Hz - sorry about the newbiesh questions, but I want to make sure I'm not making a bad assumption) is _below_ the input specs on them. (Although why the refresh rate on an _LCD_ would have a lower bound that high doesn't make sense to me - so the screen updates less often, what's the problem? It's not like a CRT, where it could cause flicker.) So I finally found an old CRT monitor that worked - but now I have another problem! It reports the video as being 35.6 Khz / 87 Hz! Which makes me worry, because I'm not sure that particular monitor can handle an 87 Hz refresh. (Parenthetically, what exactly is the mechanism that causes damage if you run an old CRT monitor at too high a refresh rate? I assume the excessive speed generates too much heat somewhere, and causes transistors to fail, or something like that?) Anyway, back to the monitor - I'm wondering if that monitor is reporting a bad number on the vertical retrace, and in fact it actually is 44 Hz? Because I found this equation to calulate the vertical retrace frequency from i) the horizontal retrace frequency, and ii) the number of lines. So I plug 35.6 Khz (which agrees with the other monitor, note) and 768 into that formula, and get... 44 Hz! So is there some bizarre interlace mode, or something, that could legitimately cause confusion over the vertical retrace? Or is the second monitor just confused? I tried to look up the video controller chip (a Cirrus CL-GD 7543 'Viking'), to see if it could even _do_ 88 Hz, but I was unable to find any documentation about it online. Also, if it really is 44 Hz, can anyone point me at an old LCD display that will handle that? (The CRT I'm currently using - another one that supposedly handles up to 100 Hz vertical retrace - takes up too much room! And there's no point getting something new - and larger - since the machine won't do anything past 1024x768 anyway.) Noel

9 years

The Great TK revival

by rodsmallwood52＠btinternet.com

Hi The great TK revival continues apace. There's a TK50 in my VAX 4000 running really well. Purrs like a cat I have TK70 in the RT-11 (11/83 QED) Machine that also runs. TK70 should read the TK50 tapes. It tries but complains about cant read the directory. So whats a common format I can write on a TK50 tape in a TK50 Drive (VMS) then take it over to the RT-11 box and have it read it.? Where is all this going? Well I need to end up with RSTS on an 11/83. So a bootable TK50 with RSTS install files on it is the goal. Meanwhile transfer by tape is useful. Rod

9 years

ISO: Terak 8510/a Keyboard and Monitor

by derschjo＠gmail.com

Hi all -- At long last my Terak 8510/a is working again! I'd repaired the power supply a couple of years back but the system simply would not behave properly. I traced it down to some very unreliable IC sockets (they were not high-quality when they were new, and the damp environment this particular machine spent several years in before I got it did nothing to help). I finally replaced about 40 sockets with some nice turned-pin ones last week, and now the system is up and running and passing the System Acceptance Tests with flying colors. I do not have a keyboard or monitor for this system, and while it's pretty easy to fabricate replacements (the video's just standard composite, and the keyboard is an 8-bit parallel ASCII keyboard with a few extra special keys) I'd love to find a set of originals. If anyone has any spares in any condition, please drop me a line. (I'm also interested in tracking down an original single-density floppy controller just on the off chance...) Thanks! - Josh

9 years

DEC's first use of PROMs

by chd＠chdickman.com

Well maybe not, but the first in the 23-001A1 sequence of part numbers was used in the PDP-8/e EAE. I was troubleshooting a problem with an EAE in which the step counter wouldn't load. There are 2 fusible PROMs in the circuit and I noticed they are 23-001A1 and 23-002A1. Maybe there is a 23-000A1.

9 years

VCFed auction update

by cctalk＠snarc.net

Apple II (Rev. 4) sold for $4,056. Sol-20 sold for $2,878. Both were clean, autographed, and working. It is likely that bidders reached a little deeper because we are a non-profit.

9 years

Set of mystery DEC boards: who can help me identifying these?

by p.gebhardt＠ymail.com

Hello list, I recently got a bunch of boards from somebody who was either not able to tell me where they were from. The boards seem to be unibus-based with numbers starting with X. I neither came across these before, nor could find any information in the web about it: Type, P/N , Description X029, 5013132B, AUC interconnect X022, 5012197C, unibuswindow X021, 5012181C, CD ROM control (did that ever exist for unibus?) X020, 5012180B, data path Two 16K mos memory modules M7847 came with the set. No backplane, unfortunately. Any hints about the type of system and application these boards were for? Many thanks for any pointers. Wish a nice weekend to all of you, Pierre ------------------------------------------------------------------------------- Pierre's collection of classic computers moved to: http://www.digitalheritage.de

9 years

thinking of the "ultimate" retro x86 PCs - what bits to seek/keep ?

by swiftgriggs＠gmail.com

Here's what I'm currently looking at (all 486's, but I'd consider 386s and original Pentiums, too): * Compaq Prolinea systems * Canon ObjectStation * NEC Powermate * HP Vectra * IBM Aptiva or PS/1 Not considering: * Beige Packard Bell with Microsoft Sound System and a 1M graphics card. :-) I'm doing my Spring cleaning. I have way too much crap, and the particular type of crap that's lowest on my list of "things to keep" is PeeCee crap. I simply have too much and a lot of it are the parts I used to make PCs bearable at the time (like combo serial/LPT cards). I'm not all that happy that PeeCees even exist, yet I have over 20 of them last I checked. I think I'm going to rid myself of the vast majority of gear that Greg Douglas of Reputable system used to haze me for keeping, calling it "PeeCee crap", and that was 16 years ago. I was asking myself, why do I have all these junky plastic laptops from the early 2k era? They are mostly soulless trash (except maybe my Sony Picturebook - yes the cute one with the Transmeta Crusoe). Wouldn't I rather purge a gaggle of laptops and a few old crappy PCs and instead have a single "special" (but much slower) 486-era box ? Yes, I would. I'm actually pulling stuff out and playing with it more. Warehousing crap is becoming less and less an attractive pastime. So, I'm thinking I'll consolidate as much of the fun hardware from the 1990's as I can in one box. That will make me feel better about ditching the considerable horde of junk I'm looking at. To that end, I have a few bits I believe are considerably more desirable compared to others and I want to get as many as I can in one box. Chime in if you have suggestions. So, here we go, in no real order: * I want to stick with desktop or tower units only, no laptops, I'll probably have to add some PCI cards to get to "ultimate" status :-) * I'd use it with one of these OSs: *BSD, Linux, Solaris x86, OpenStep, BSDi, Unixware, Minix, MS-DOS, DR-DOS, FreeDOS, or OS/2. Thus the more compatible stuff is worth considering. Windows compatibility isn't something I care about ('cept maybe for comic relief, which I can get much more easily from politics these days). * Anyone know of a box with a built-in (integrated) Gravis Ultrasound? That'd save me a slot. However, there isn't much to compete with that card from the 90's. The SB16 was ubiquitous and worked well enough, but I didn't feel it could compete with a GUS. The SB16 wasn't the "ultimate" for sure. * Hmm, Symbios, LSI, or Adaptec on the SCSI controller.... OR! Maybe someone knows of a cool PC that had a built-in SCSI controller. I don't think I could abide PATA/IDE disks and for-sure no MFM/RLL drives (the horror). The nice stuff in the 90's was always SCSI, IIRC. I remember some NEC PCs that were pretty attractive and came with integrated SCSI. * I hate machines that used custom RAM. I guess it wouldn't be a deal breaker if it was already maxxed. * I'd certainly prefer PS/2 keyboard ports. * Slimline or other nice case designs are very much something I'll look for, but I need at least one PCI slot, methinks. Unless I could get a GUS and SCSI controller both integrated (man, wouldn't that be something!). Anything different or spacey is preferable to a beige box, even if it's just white or black. * Hmm, what was the ultimate PC framebuffer from the 1990s? I guess it depends on if you care about 3D or think it was too crappy in the 1990s to consider. I'm mostly in the latter camp. So, I'm more inclined to go for maximum 2D performance and maximum OS compatibility. Number Nine? Orchid? I guess I need to find some 2D performance benchmarks from 1999 or something similar. Matrox might work out. The MGA Millennium II comes to mind. I liked 3DFX, too, but I'm worried they were too 3D centric, plus they were ignored by the commercial Unix players. More video memory is great so it can run higher res where possible. * I'll use a 3Com 3c905, but I remember there being even better stuff. I'm just not sure which one is going to work best for all my OSs. Maybe the 3C509 is a better choice, but it's 10mbit and ISA, IIRC. I just remember that card works in more OSs than anything I've ever seen. Realtek is out. I won't use those PoSs ("fool me once" and all that). I'm also not a fan of Broadcom (again they burned me too often). * NTSC Video capability would be nice, but I'll probably just add it in the form of an old Happauge PCI WinTV. I need to find out what OpenSTEP and others supported. This is just a "nice to have" for me. I really liked things like the MacTV (all-in-one with NTSC tuner) back in the day. * Since I'm mostly looking at 486's, I'm mainly targeting the 486/66. I have nothing against Cyrix or exotic x86 processors from the era. -Swift

9 years

media and software

by sales＠elecplus.com

I am going back to Dallas next week to sort 2 pallets of media and software. The age runs from reels of tape (9 track? Dated 1989 and earlier) to LTO4. Software, there are a LOT of MS Developer CDs from 2011 and much earlier, Xilinx CDs, AIX CDs, Solaris CDs (the earliest I noticed off the bat was version 6) and a lot of Dell server implementation disks. Also some things on cassette tapes. I need to know what is wanted. After next week it goes in the dumpster. Cindy Croxton Electronics Plus 500 Pershing Ave. Kerrville, TX 78028 830-370-3239 cell sales at elecplus.com AOL IM elcpls

9 years

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test-drb June 2016