test-drb

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101090 discussions

by mattislind＠gmail.com

I have a few 8 inch floppy disks coming from a Q1 Lite computer. I tried reading them on a PC with a Adaptec 1522A floppy controller but it failed completely. Then I tried my Catweasel and dumped the raw flux data. The format differs >from what I have seen before. I did a quick histogram of the flux lengths and it appears that there are four groups of sample lengths evenly spaced. Peaks at 30, 48, 66 och 84 samples flux lengths. The longest flux lengths are interspersed in between more normal flux lengths in the actual data and I get the same type of result regardless of reads of the same track and between different tracks. But the relative frequency is much much lower for the longer flux lengths than the shorter ones. An RX02 (MFM ish) had 26, 41, 55 samples as the peaks in the histogram. As far as I understand cw2dmk software uses 14 MHz setting in the catweasel so each sample length is around 70ns. Anyone that has seen this kind of format before? Or is it just a reading error? I have the same result from several discs though and they look to be in quite good shape physically. Link contains histogram files and a raw track flux file. https://drive.google.com/drive/folders/1URC5i8AsRyP08d_ZhWRovbDp2TMgdj4B?us…

5 years

TK70 maintenance--swapping capstans

by cz＠alembic.crystel.com

Well my little TK70 here has been squeaking and it looks like the capstans are frozen/bad. They don't move up and down and they don't spin well. Fortunately I have a dead TK70 with good capstans so I figured I would swap them. Unfortunately I don't have a maintenance manual (does anyone have one?) so I had to figure out alignment myself. Capstan alignment seems to be critical, if they are off the unit don't work... Anyway here is my procedure so far to get the unit to load and unload tapes on the bench. Not perfect, but a start.... Pulling the capstans requires you to remove the two lock nuts on top first. I recommend you count the turns from all the way tight if possible as alignment is critical, and the front and rear ones can be at different relative heights. Anyway if you didn't do this you need to adjust the rear height to trip the optical sensors and the front one to handle tape slew. Note: All the below is done with the unit on a bench, with a PC power supply. The first step is to adjust the rear capstan so the leader tape's wide hole for the end of tape-stop marker allows light from both LEDs/sensors to pass through. You do this by tightening the bolt down till snug, then back off 1/2 turn. Turn on unit, see if it unlatches. It probably will try to turn the tape 4 times then error out. Fine. Power down, back off the bolt 1/4 turn and try again. At some point it will open the latch. Note the # of turns of the bolt then keep going 1/4 turn at a time till it doesn't work again (too high). The proper value for your unit in turns is halfway between too low and too high. Reset the bolt and verify it works several times. For my unit the right height was about 1.5 turns out. Then you need to adjust the front capstan. The problem is if the front is higher or lower than the back you have tape slew errors. Start at the level of the rear one based on the # of turns minus a bit (1/2 turn). Then load a tape. It will load, but when you try to unload things will go bad, the tape will just move forward onto the take up reel 4 times, and the unit will error out. The reason is it has to read the tape as it turns to know a tape is loaded (as opposed to the leader where it looks for the end of leader light). If the capstans are not holding the tape level against the head it can't read. Each time it moves forward a bit, try bringing the front up 1/8 turn at a time. Eventually it will speed up, that means it can read the tape on one of those moves. It should then unload. Now you have the front basically set. It will unload the tape, cycle it a few times to make sure it's working. That's where I am now. Next step is to see if it will read the tape in the computer. I'll work on that tomorrow. Note if you ever shine an led flashlight into a running TK50 or 70 all hell will break loose as the system will see the light on the tape sensor and think it has hit BOT. Even worse is if both LED sensors trigger, then it thinks it is at end of leader and it will throw tape everywhere. Ask me how I know....

5 years

WTB: HP 9000-340 memory (HP 98268A), AUI (HP 98235A), SCSI (HP 98658A)

by cmhanson＠eschatologist.net

I've acquired an HP 9000-340C+ and I'd like to kit it out with the maximum RAM, SCSI, and AUI rather than thin Ethernet. Desired: - RAM boards: HP 98268A RAM board (three of them to get to 16MB, I'd probably buy extra just to be safe) - AUI LAN board: 98571-66534, aka HP 98235A AUI LAN Upgrade - SCSI board: HP 98658A SCSI Interface Card Anyone have any of this stuff that they might be interested in parting with? I'm also always on the lookout for an HP 98556A 2D/integer graphics accelerator in case anyone happens to have one that needs a home. That's the integer accelerator with a 68020 and some RAM, which piggybacks atop the 98550A (1280x1024 8-bit color card) via its extra Eurocard connector. -- Chris

5 years

Systems Concepts SC-4 computer

by jnc＠mercury.lcs.mit.edu

> From: Lars Brinkhoff > I suppose that main computer could be the GE-645 on which Multics was > developed? And they would still refer to it as G.E. Oh, it was clearly referring to the Multics machine. I assumed that with the GE sale being 1970, by '72 it was not a GE machine anymore. But the MIT Multics site page: https://multicians.org/site-mit.html says the H-6180 was installed in November, 1972; shortly after the letter. Noel

5 years

found it: first speech synthesizer (at least, for S-100 systems)

by couryhouse＠aol.com

Have one filed in somewhere with all the s-100 boards... now I have a reason to dig it out! Yes... memories of Wirt's projects! Ed#?? smecc On Wednesday, December 16, 2020 Bill Degnan via cctalk <billdegnan at gmail.com; cctalk at classiccmp.org> wrote: Very interesting Stan. Thank you for sharing this info Bill Degnan On Wed, Dec 16, 2020 at 2:43 AM Stan Sieler via cctalk < cctalk at classiccmp.org> wrote: > Hi, > > Some years back, I was asking if anyone had information about the speech > synthesizer > developed for the Altair 8080 by Wirt Atmar of AICS (in New Mexico). > No "hits". > > Most places on the web claimed the Computalker was first, given the date as > 1976 or 1977. > > (Earlier speech synthesizes existed, but they were external boxes that one > interfaced to, > or were standalone (often with a large/weird keyboard).) > > Today, I stumbled over a fairly bad OCR of Byte magazine from August, 1976 > at > > https://archive.org/stream/byte-magazine-1976-08/1976_08_BYTE_00-12_Speech_… > > It has two articles about speech synthesizers for S-100 bus systems. > > The first is by the Computalker people, who say: > > At the time this article > goes to press, a synthesizer > module incorporating several > detail refinements and im- > provements over the circuits > of this article is being de- > veloped by the author and > associates. > > and > > A detailed user's > guide will be supplied with the > Computalker module > > > Note the future tense! > > The second is by Wirt Atmar, whose product *was already shipping*. > > Near the end of his Byte article, Wirt lists currently available products: > > At the present time, two speech synthesizers > are both commercially available and affordable by > the hobbyist. > > One is the Votrax produced by: > > Vocal Interface Division > > Federal Screw Works > > 500 Stephenson Dr > > Troy Ml 48084 > > Price, approximately $2,000 > > Interfacing: Parallel or Serial (RS-232) > > > The second is the Model 1000 manufactured by: > > Ai Cybernetic Systems > > PO Box 4691 > > University Park NM 88003 > > Price, $425 > > > Wirt had told me (twenty years ago or so) that he thought his was the first > for microcomputers (e.g., a user installed card, not an external box). > Now, I'm sure ... but it was realllly close! > > Wirt demonstrated his product at the earlier MITS World Altair Computer > Conven- > tion, where it won first prize. > > He advertised it poorly/infrequently, since it was mostly a side business. > And, that shows, since history doesn't remember it. > > Stan >

5 years

Plessey/Dilog DCV54

by nw.johnson＠ieee.org

Has anybody got a DCV54 that they are using? I am trying to get one working with David Gasswein's mfm board and having no luck. The controller is working fine with a standard floppy as an RX33, even boots the MicroVAX from it.? But on-board diagnostics cannot format or even recognise the mfm board as a winchester. Just got the scope out today and found that the drive select lines are being terminated OK on the mfm board, bit the controller is not even dropping drive select. (Yes I have tried new cables) Problem is I don't have anything old enough to test the mfm boards with other than the Plessey controlelr! I'm thinking there must be some on-board config that I am missing on the controller. - It has never had a real mfm drive connected to it. Any help appreciated, Nigel -- Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU Amateur Radio, the origin of the open-source concept! Skype: TILBURY2591 nw.johnson at ieee.org

5 years

Digitalker 54104 IC

by couryhouse＠aol.com

Bill...this just? struck a memory I think I have a Radioshack Digitalker in a packaging? but recall it being just one large chip...? Ed #??? SMECC On Saturday, February 13, 2021 Bill Gunshannon via cctalk <bill.gunshannon at hotmail.com; cctalk at classiccmp.org> wrote: On 2/12/21 6:09 PM, Ethan Dicks via cctalk wrote: > On Fri, Feb 12, 2021 at 6:01 PM Jim Brain via cctalk > <cctalk at classiccmp.org> wrote: >> But, I'm sad because no one either has one nor can help me test this >> one.? So, I cannot enjoy the thrill of making it say inappropriate stuff :-( > > I have several vintage speech ICs, but not that one. > I do as well.? I have the Radio Shack "Voice Synthesizer IC Set" sitting on the desk in front of me right now. bill

5 years

Wanted: Info on Optisys/Optidisk WORM file system

by cclist＠sydex.com

I have a bunch of Panasonic/Matsushita 470/940 MB phase-change WORM discs here--and the appropriate drive (Panasonic LF-5010 SCSI-2) to read them. Unlike CD-R media, however, the format of these discs is not anything standard--they were essentially treated as hard disks. So, adding a file involves copying the directory and then adding the file information to the copy. The same applies, of course, for file deletion. If the drive tries to read a (1,024 byte) sector that hasn't been written to, it will get an error after a number of retries. I should emphasize that this drive is *not* fast--throughput seems to be on the order of a floppy disk. I can probably (with a bit of head-scratching) figure out the methodology behind this system, but I'm giving a shout-out to see if this rings any bells. Phase-change WORM did not enjoy a long life in the world, being superseded by rewritable media (both CD-RW and MO). As a point of reference, here's the data from sector 1 of a sample disc (Sector 0 is not used): > 00000400 04 0d 04 16 00 0f 0a fe 02 00 20 03 00 03 48 47 |.......... ...HG| > 00000410 49 42 32 2e 31 31 2d 30 33 2e 30 30 43 72 65 61 |IB2.11-03.00Crea| > 00000420 74 65 64 3a 20 54 68 72 20 32 32 20 41 70 72 20 |ted: Thr 22 Apr | > 00000430 31 39 39 33 20 20 20 20 20 31 35 3a 20 32 2e 32 |1993 15: 2.2| > 00000440 38 3a 35 31 20 20 20 20 4f 70 74 69 73 79 73 20 |8:51 Optisys | > 00000450 4f 70 74 69 44 69 73 6b 20 28 43 29 20 43 6f 70 |OptiDisk (C) Cop| > 00000460 79 72 69 67 68 74 20 31 39 38 37 20 2d 20 31 39 |yright 1987 - 19| > 00000470 39 31 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |91 | > 00000480 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | If nothing turns up in the community, I'll work out the format and make details available (as I understand them). TIA --Chuck

5 years

Digitalker 54104 IC

by couryhouse＠aol.com

Most challanging was to figure out to make it say naughty things... and once you did? how it almost caused havoc in AZ On Tuesday, February 9, 2021 Jim Brain via cctalk <brain at jbrain.com; cctalk at classiccmp.org> wrote: I suspect the answer to question #1 is no, but thought I would ask. 1) Anyone happen to have a known working Digitalker 54104 IC they are looking to trade for some cash that does not involve me selling an arm or a leg :-)? 2) Barring that, anyone have a known working Digitalker-based unit that might be able to pop in a suspected non working Digitalker IC and test? I have a Jameco (yep, the parts firm) manufactured Digitalker unit here called the JE-520 that is my original unit.? It suffered some ROM bit rot long ago and was not working, but I acquired the ROMs a while back to repair the unit. Now, though, as I pull it out for another project, it seems to be misbehaving.? It's like "address bit 1" on the input commands is acting up.? For instance, word 48 is "zero", and 49 is "one", but zero will be followed by "three" and then "zero" and then "three" as one sends values 48,49,50,51 to the unit.? I'm working to confirm the bit 1 on the cable to the PC is not bad, but initial efforts point to it being the IC. Jim -- Jim Brain brain at jbrain.com www.jbrain.com

5 years

Mystery (unusual) 1973 terminal

by jules.richardson99＠gmail.com

Hi all, Hopefully the following link works, but someone over on one of the Facebook vintage groups has this oddball terminal from 1973 that they've been looking for any information on: https://drive.google.com/drive/folders/1-2uEFbi3OKBYr06y6yHnygDiLMtw2Qkj ... it's somewhat unconventional in that half the CRT is hidden from view within the machine, i.e. it only actually displays the top half of the display to the user - I've no idea if that's because it had a specific application where space was limited, or if it was simply that memory at the time was horribly expensive and so it was designed to only use a few lines (I know some vendors did that, although I think they typically presented the whole CRT and at least had the option of RAM upgrade to more lines). The blower assembly seems a little on the homebrew side, but on the other hand the PCBs and case construction make it seem like a professional product. The owner says the only label anywhere on the thing is the one on the CRT saying "Mfd in Japan for Conrac", but that's presumably just the CRT itself and not the entire machine. I don't believe there's anything resembling a microprocessor in the system, it's all just TTL logic (the large white ceramic IC is an ACIA). Oh, I believe the owner's in Canada, so it may be it was made there and never exported to other parts of the world. cheers Jules

5 years

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