test-drb April 2005

test-drb@ccmp.vtda.org

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heavy metal

by jack.rubin＠ameritech.net

some ideas on managing a collection of vintage equipment - http://www.qsl.net/vk2dym/radio/collection.htm

19 years, 8 months

Soviet Punch Cards

by vcf＠siconic.com

No big deal, just thought it was mildly interesting... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5189823717 -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]

19 years, 8 months

Good CD-R media (T-Y CD-Rs)

by Saquinn624＠aol.com

My memory might be a little fuzzy, but I think that there was some talk about how to find good CD-R media a bit ago. I was just looking around (finally got to Fry's) and found some Maxell "CD-RPro" disks that were Tayo-Yuden manufacture. Packaging even said "Made in Japan" Salesman didn't have any idea about Japanese disks, though, and pointed out "other same brand disks" available in larger quantities [Taiwanese, probably CMC] So, they are there, but only in quantity 25 spindles. Perhaps a E-mail campaign to Maxell letting them know that we approve and notice would encourage them to stay with T-Y? - Scott

19 years, 8 months

Intergraph fans...

by pmackinlay＠hotmail.com

Just a short post to introduce myself and what I'm up to... I'm currently looking into one of Intergraph's old InterPro systems (a 2830) and trying to dig up enough documentation to allow me to ultimately port NetBSD to the box to replace the native CLIX (an old SYSV 3.2ish Unix). Have made some pretty good progress on disassembling the boot EPROM and writing the beginnings of a hardware simulator. After discovering the CLIPPER CPU book online (not to mention the DP8510 BitBlt unit databook!), I think my off-the-shelf chip documents are almost complete. Information on the custom ASICs is almost nonexistent, but the system diagnostics provide some good reference code which should provide useful information. I'm curious to know if there's anyone else out there that's interested in these relatively rare boxes? For anyone that cares, the basic hardware in the box is: C4M CLIPPER CPU at 70MHz, ECC RAM Zilog 85C30 SCC and 85230 ESCC - one port used by keyboard, other three available Xilinix XC3020 fpga controls Versatec, Centronics or Intergraph compatible plotter interface Intel 82596 ethernet controller NCR53c94 SCSI host controller NEC82077 floppy controller Dallas DS12887 RTC and NVRAM 128k boot UV EPROM 2x128k diagnostic/boot flash EPROM The graphics board is built up with: DP8510 BitBlt unit (x2 on dual head board) custom Bresenham line-drawing ASIC bt459 DAC (x2 on dual head board) 2x1M VRAM (double buffered), (x2 on dual head board) The real key to the missing documentation is the remaining IOGA and SGA custom asics on the system board. Anyone who has any other documentation on this stuff would be a friend for life ;). Regards, Pat Mackinlay.

19 years, 8 months

Crazy Transformer question

by healyzh＠aracnet.com

OK, this is a really bizarre question. My Neo-Geo arcade has been acting up, and a couple weekends ago when I tried to take a look at it, I couldn't even get a picture. Today I got the bits to take out the security screws so I could get into the part where the powersupply is. It was just up for 4 1/2 hours without any problems. The only things that have been done is to wipe the grill where the fan is off (it was really filthy), and to move an old sewing machine that was sitting on the floor next to it (unplugged). The sewing machine was sitting next to where the transformer is in the cabinet. Is there any way having it sitting there could have been effecting the power? It's a really stupid and bizarre question, and I don't see how it could effect it, but I can't figure out why the system seems to be working now. Of course a more logical explanation is that there is something loose inside. Zane -- -- | Zane H. Healy | UNIX Systems Administrator | | healyzh at aracnet.com (primary) | OpenVMS Enthusiast | | | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | PDP-10 Emulation and Zane's Computer Museum. | | http://www.aracnet.com/~healyzh/ |

19 years, 8 months

my Data General Nova 4/X, disk woes continue

by ajp166＠bellatlantic.net

> >Subject: my Data General Nova 4/X, disk woes continue > From: Tom Jennings <tomj at wps.com> > Date: Sun, 24 Apr 2005 16:55:35 -0700 (PDT) > To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org> > >I've been working on my car project >(http://wps.com/AMC/1970-AMC-Hornet/index.html) because car season >is coming up soon enough, but I peeled time out for the Nova here >and there. > >I originally repaired a popped +5V logic bypass cap on the >Read/Write Board, (some monolithic ceramic job), and changed all >the funky old caps for new ceramic disks. That worked for 20 - 40 >hours of operation without a single error. Disk had formatted with >zero media defects. Then the disk started throwing read errors >that moved around (bad blocks later good; more and more bad >blocks...). Diagnostics never indicated any error other than read >errors; seek, format, diags all run 100% perfect except read >errors. > >I suspect the Read/Write Board. So I ordered modern monolithic >replacements for the remaining old mono chips from Digikey, and >shotgunned all the old electrolytics etc for good measure, in two >places electrolytics replaced with tantalums (didn't have >..82uF's). I hope they are not in any timing circuits. Another way to really shoot ones foot is change all logic and any analog stuff or worse digital used as analog. Newer or older parts often will behave different and at 10mhz that was high speed then. There be serpents and devils lurking there. >Formats, reads OK, then errors again! Sheesh! System has been on >for two hours (I'm getting paranoid, so temp stabilize the whole >thing); halted diags, loaded disk heads, installed drive cover, >pushed into the rack, left for an hour for the drive temp to >stabilize (this is a religious rite, might as well kill a chicken) >then format and test again. This tells me you've not looked at the cause only apparent problems that may not be relevent. >After warm-up, it's worse. Signals all through the path look >OK, hot and cold. I can see no difference, but this is 10 MHz >NRZ data, in a two-state amp with AGC. I think I'm screwed. > OK, the drive uses the same CART as a DEC RL01/02 and the base design is a CDC creation if memory serves. DEC nor DG designed the beast. There are two things to pay attention to. Servo amps for the positioner they are analog and can drift. They must be set up at TEMP. If I remember that varient of the drive also had embedded servo information for the head position controls. The second is the read/write electronics have a PLL for read clock recovery. If thats not set up right it will drift outside the lock in range and start tossing errors. It also must be setup at working TEMP. The PLL is to track drive speed errors and irregularities in position and bit shifting. Did you mean "two state amp" or "two stage amp"? Likely it's not an amp problem, a quick look with any old scope could check that as it warms up. >The R/W board is a piece of work too. I suspect it's an early >revision, as the board is a hack job, covered in cut traces, >components and jumpers on the bottom, and there's a !#$%!! trimpot >crammed in somewhere as well as kludgey RC (lopass) networks in >some digital logic. Plus, the PC board was milled out for access >to a middle layer. Not Good. Plus, it doesn't match the schematic >(though it's close enough to poke around in with a scope). Early disk systems like that seem to have their fair share of green, blue or white and red wires. Grean being factory changes, white or blue were often depot repair and red field implemented. I'd not be too concerned if it worked before it should again. Allison

19 years, 8 months

Intel Multibus proto board (maybe front panel?) available

by wh.sudbrink＠verizon.net

Hi all, The one thing I purchased at the recent TCF flea market was a box full of raw copper clad and proto boards. I was hoping that there was an S-100 proto board in the mix, but alas, there was not. Anyway, among others, that I may offer or ask about later, there was this Multibus proto board. It looks like a front panel implementation. There are six TIL3xx LEDs arranged 4 - 2 and several sets of DIP switches as well as some TTL logic and coax cables maybe intended for probe hook up. There are pictures here: http://wsudbrink.dyndns.org/images/intelmbus/ I just realized that I didn't take any pictures of the back. My camera batteries are recharging, so I'll add some later but here's a quick description... The board is wire-wrapped. It seems in pretty good shape, a few of the pins are slightly bent but none seem to be broken. A few of the wires are broken but it is clear where they were routed to. Looking for trades, especially Ohio Scientific but I'd probably take a couple of S-100 proto boards if nothing else. Unfortunately, the previous owner was a fast hand with a hack saw and I also have the remains of a couple more Multibus proto boards (no components on them) if anyone is interested. Bill

19 years, 8 months

looking for IMSAI IM-48 docs

by ajp166＠bellatlantic.net

Every so often I put this up in various places.. I'm looking for schematics and otehr useful info on: IMSAI IMP-48 Thats a single board computer that IMSAI did using the Intel 8048 family chips. On board items are keypad and LED display to interact with a monitor program in Eprom. Also is 1k of user program ram for applications, ofcourse the 8035 romess 8048 plus IO interfaces that include casette tape, relays and TTY. I've had this one for 25+ years and have not seen any others. The one I have is working, it's traced it out and use it for occasional 8048 projects. Allison

19 years, 8 months

I'm going to design and build an X terminal

by msokolov＠ivan.Harhan.ORG

Jules Richardson <julesrichardsonuk at yahoo.co.uk> wrote: > Do you need audio at all? No. Audio does not belong in X and I actually never even suspected that there was an audio extension for X until I heard people on this list complain that Classic X terminals don't have it. Spoiled kids! :-) > > My tentative PowerPC CPU choice is MPC8250. > > Does that need a cooling fan? I think it's a low-power CPU like other PowerPCs I have worked with, but I don't see any problem with putting a little fan in the box. My goal is not to have a fanless box on my desk, but an OSless one, or more precisely without a user-accessible OS that needs system administration. MS

19 years, 8 months

small valves and RE: OT

by ajp166＠bellatlantic.net

> >Subject: Re: small valves and RE: OT > From: ard at p850ug1.demon.co.uk (Tony Duell) > Date: Sat, 23 Apr 2005 23:45:16 +0100 (BST) >It would be interesting to know what's going on in this set. Can you get >a schematic? Being an American set, it's not in Poole and Molloy :-( It's an RCA 8BX5 lineup is 1R5, 1U5, 1T4, 3V5 and 117Z4 if memory serves. I don't have the schematic for the set. I expent I could find it if needed. Being functional I'm reluctant to tear into it and hand draw the schematic. If it breaks I will. Believe it or not I use it to listen to local station for ball games. >It's one of the better electronics magazines available over here. It has >some interesting projects, and they've now started making microcontroller >source code available for most, but not all, of them. I know the magazine, rarely see it. >The circuit in question was a pretty standard inverter circuit, running >at about 50Hz (not a typo, they wanted to keep RF noise down), feeding a >normal mains transformer used in reverse. Looks like it should work with >no problems. I've done this before. The simple version use saturated switching transistors and tend to have high noise due to high current spikes >from charge storage in the transistors. I usually run them at 100-400HZ with a common mains transformer for better filtering and use a bit of feedback to run the switch transistors such that they are turned off before the core saturates. The end result is less current, better efficientcy and less noise. It's a side effect of my years of working with older commercial VHF/UHF twoway radio that used things like vibrators, Dynamotors and even transistors for generating HT. Often the hybrid and tube radios would be in service for years after expected retirement do to replacement cost. The result was desinging and implmenting replacement circuits that would replace sometimes hard to find hardware, especially those dynamotors. Allison Kb1gmx

19 years, 8 months

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test-drb April 2005