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What retro computer activity did you get up to today?

Discussion in 'Retro & Arcade' started by adz, Jan 28, 2014.

  1. GumbyNoTalent

    GumbyNoTalent Member

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  2. elvis

    elvis Old school old fool

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    My first "real job" was as a sysadmin for a large global architecture firm. I used to nerd out on their massive plotters and printers pretty hard.

    That job sparked my entire love for colour science.
     
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  3. GumbyNoTalent

    GumbyNoTalent Member

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    I saw my first commercial plotter late 80s early 90s drawing large scale schematics for aircraft, mesmerized I was for hours.
     
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  4. CRTified

    CRTified Member

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    Had a large scale HPGL mechanical plotter amongst my kit at work, engineering firm, back about 2000.

    Even back then it was mostly phased out in favour of electronic as that became cost effective. Space effective too - the old plotter is bigger than a foosball table, vs a Designjet or big Canon. Oh, and the noise. I had a few days of having to drag that thing into a tiny side office and close the door, then stay in there babysitting it for 2 hours while plotting off a set of drawings.

    Any kind of software or driver was lost to time by a past generation, so I had to use a cobbled-together suite of custom tools to prepare the plot data, then use the DOS command "copy file.hgl > physical port" for each print.

    All that said. Fucking fascinating, maybe the "coolest" machine I've ever seen. The vacuum-sucking of the page onto the bed, like a reverse air-hockey table. The insane speed of the mechanism as it Terminators it way around the page, zipping from place to place and incrementally filling in different segments of each drawing object seemingly (but not truly) randomly. The robotic changing of the pens to different thicknesses and colours.

    Then the more humourous side: The process of preparing the pens and getting ink all over your hands if you're lucky. The pen which stops working, or blobs halfway through the 10 minute plot. The pen which malfunctions and stabs into the paper one lucky day, tearing it 10,000 new arseholes in 3.21 seconds. :lol:
    --
    Can't be arsed linking it, but spot the fun cameo in LGR's latest video (huge retro unboxing) at about the 7 minute mark, some of you at least are probably familiar with (the website/book of) the fine fellow who sent Clint a mousepad and, err, a coin.
     
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  5. sammy_b0i

    sammy_b0i Laugh it up, fuzzball!

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  6. DRAGONKZ

    DRAGONKZ Member

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    Unboxed some spares, including some Midway Quicksilver 2 PCs… they need the 20 years of dust blown out of them!

    CF6A945B-9C77-4BBB-84A7-D261246FA0AD.jpeg 6B61A13B-9D1B-4F5F-A67A-8CE0569BC51A.jpeg
     
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  7. rugger

    rugger Member

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    Over the weekend, I fixed up an old ET4000 card:

    IMG_1442 (2).JPG IMG_1443 (2).JPG IMG_1444 (2).JPG

    The VGA port was damaged internally, making the VGA connection less than perfectly reliable, so I decided to replace it with a spare port I had. (First picture shows the board before removing the last of the burnt flux, final picture is after cleaning)

    The process for doing this is new for me, but worked exceptionally well, with no damage to the PCB and a very clean result.

    How I did it:
    a) Add fresh leaded solder to the 2 support posts, then wick away a significant proportion of the solder off these posts. This works to lower the melting point of the solder on these posts.
    b) Come in with my hot air rework station gun, and heat the back of the board until the entire VGA port comes off. This takes a few minutes, and you want to heat the board around the VGA port up a bit as well to prevent too much thermal stress.
    c) Clear all the holes with my soldering iron and wick.
    d) Solder in the new VGA port.

    As you can see, using hot air to remove the old port left the board in immaculate condition, while actually being fairly easy.
     
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  8. rugger

    rugger Member

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    And to document the repairs on the 486 PC-chips board I bought several months back ... my first serious battery corrosion repair.

    IMG_1445 (2).JPG IMG_1446 (2).JPG IMG_1447 (2).JPG IMG_1448 (2).JPG

    And I can say it largely works nicely now:

    The entire story of this repair is:
    a) Remove and document all the components near the corroded areas. This includes the totally destroyed BIOS chip socket and the jumpers around the battery.
    b) Take close up photos of the traces, back and front, in the areas around where the corrosion is.
    c) Use Dremel with wire brush to gently remove all the conformal coating on the affected copper tracks.
    d) I sit down in paint in Windows and draw over the top of each trace, drawing red and green lines for bad and good traces.
    e) For every non-working trace, I run a bodge wire on the bottom of the board to re-establish the connection.
    f) I reinstall of the components on the top side of the board from where they come. Install new bios socket and
    g) Clean the significant corrosion on the legs of the bios chip, and use my computer to make a backup of the BIOS chip.
    h) Reinstall everything.

    And yes, it doesn't work. Still, the ISA bus does nothing and there is no evidence the machine is working.

    So I put aside the repair until I get my oscilloscope. Using the oscilloscope, I am able to determine that clock is working and reaching the CPU, and that the CPU and BIOS chips are sorta-kinda communicating. So I mess around for a couple of hours, and finally decide to double check that all the data/address lines from the ISA is actually reaching the chipset.

    And eureka, I found one data line trace that I thought was good, but was actually bad. So one more bodge wire, and suddenly the system roars to life.

    From there I play with it and worked out a couple of additional fixes:
    a) Old Award BIOS doesn't accept 2021 as a valid year. Fix for this is fairly simple, https://www.vogons.org/viewtopic.php?t=76349, so I edit this fix into the EEPROM and write a new EEPROM for the board. I had to use another EEPROM chip because the original BIOS chip (pictured with the board) is a one time programmable EPROM, basically a EPROM with no window for erase. With the modded BIOS, it will take a 2021 year and not think it is 2094. The reason for this is that the buggy bios thinks the minimum acceptable year ends in 94, so it clamps 2021 to 2094.
    b) I had a whole lot of weirdness, with some ISA cards causing keyboard problems, or not being recognized, when plugged into some ports and not others. As it was a keyboard error, and seems to be triggered by plugging an ISA card into the slot closest to the keyboard port, I suspected it was to do with the keyboard bodge wire I used. This is the long wire. I decided to try wiring the bodge wire right to the pin of the keyboard data port. And what do you know, it works a lot better there. Given that having the trace go right to the keyboard port wasn't quite right, as all keyboard I/O is fused, I ended up moving the keyboard bodge wire to the new place as shown in my pictures, which is on the protected side of the keyboard fuses. I worked out I originally had it wired to the wrong side of one of the resistors on the keyboard input, resulting in a weak signal being propagated, or maybe introducing an incorrect signal into the keyboard data path.

    The only weird thing with this board is that it does not like Windows 95 at all. It installs and everything, but I get hard drive lockups during high I/O load. The ISA bus is still working, as the mouse cursor still moves, but nothing else responds. Works fine in windows 3.1 and DOS though, so it makes it a good motherboard for those operating systems.

    The ugly side of this system (and probably many others) is that the ISA bus is routed under the Varta battery! It is routed this way because the board goes Chipset -> BIOS chip -> ISA bus in that order for the ISA bus. It is basically a time bomb waiting to go off.
     
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  9. Pierre32

    Pierre32 Member

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    Extremely neat VGA port replacement, and impressive mobo recovery! Great rescues :thumbup:
     
  10. CRTified

    CRTified Member

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    Thanks for the write up, this kind of thing is extremely interesting. My expertise at that level largely consists of fascinated watchings of necroware and other such videos. Never taken on a corroded board myself, yet. Figure it's only a matter of time.

    I noticed that he tends to chemically neutralise the pH of the corroded area with white vinegar (iirc) as part of his corrosion repair process. Do you also attend to that somehow?
     
  11. rugger

    rugger Member

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    Yep, I do remember doing that very early in the process, but most of the cleanup work was done afterwards with the dremel and wire brush to expose the damaged traces, and to work out what was actual copper and what was just pure corrosion.

    You don't want to go nilly willy with vinegar either, as it is also corrosive.

    For this sort of work, I used a desoldering station and a good soldering iron. I'd probably do the next one with hot air and then wick, rather than the desoldering station, as hot air is so much more gentle on the pads and traces.
     
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  12. rugger

    rugger Member

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    Speaking of necroware's youtube channel, I think I got the idea to use dremel with wire brush from him. I did start with fiberglass pen, but wasn't too sold on it because I'm not a fan of fiberglass splinters!
     
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  13. proffesso

    proffesso Member

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    managed to nab myself a 14" PVM (14N6A) now just need to get some hardware to plug it all up!
     
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  14. Pierre32

    Pierre32 Member

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    Nice, I hope you still have both kidneys.

    That reminds me, I saw this Samsung SMC-210P on a walk the other week. Composite & Y/C only. I wasn't in a position to lug it away for testing.

    upload_2021-11-10_15-19-33.png
     
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  15. sammy_b0i

    sammy_b0i Laugh it up, fuzzball!

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  16. Pierre32

    Pierre32 Member

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    A couple of months back, my 386 threw some more tantalums and stopped booting. Hopefully a recap is all it needs, but that's on the backburner for a bit. I was just about to kick off some playthroughs on it too. So I've brought the P200 Voodoo system front and centre to fill the role.

    upload_2021-11-10_17-30-3.png

    Inside, I'm trying a new concept in audio: RGB Sound™.

    upload_2021-11-10_17-33-54.png

    At top is a PC MIDI card from Keropi, with an E-Wave board from Serdaco. Next is the Bluepoint sound card I picked up last month, and then of course the GUS.

    After taking the pic I plugged in an ISA NIC above the PC MIDI card, filling the last available slot in the machine. Not fired up and configured yet - but I'm sure it will all go smoothly!

    upload_2021-11-10_17-41-3.png
     
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  17. badmofo

    badmofo Member

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    :lol:

    Cool system - what are those black drive covers? 3D printed or painted originals?
     
  18. Pierre32

    Pierre32 Member

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    Poorly painted originals. Which I didn't mind doing, because the originals weren't actually original, and came out of the spares pile in different shades. I wouldn't mind redoing those with some texture.

    [edit]

    So yes, firing it up with all cards in was ambitious. Stack overflow and system halt on boot! I haven't had that one before. I pulled all the ISA cards except the Opti, and grabbed the DOS drivers from here.

    Setup took a bit of figuring out. You configure the card with SNDINIT.EXE, but that won't run without the SOUND16 variable set. So you need to run these in order:

    Code:
    SET SOUND16=C:\OPTI
    SNDINIT.EXE
    Then you get quite a nice GUI config:

    upload_2021-11-10_23-46-36.png

    It added the SET BLASTER line to autoexec, but I had to add the other three entries manually:

    Code:
    SET BLASTER=A220 I5 D1 T4
    PATH=;...;C:\OPTI
    SET SOUND16=C:\OPTI
    C:\OPTI\SNDINIT /B
    Volumes were a bit wonky initially (very quiet FM) so I jumped back into SNDINIT to fix them up. Then I plugged the PC MIDI card back in, and with no further config required they were singing together nicely.

    GUS time. I tried to drop it in with the same config used on the 386, but the P200 didn't like it. The setup program won't even assign addresses on this machine. But it can be configured manually. After an hour of baffling issues I finally realised I had one address wrong in the config, and everything sprang to life. RGB Sound unlocked.

    Finally I plugged the NIC back in, and no stack overflows now.
     
    Last edited: Nov 10, 2021
  19. elvis

    elvis Old school old fool

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    Hey now this is cool:
    https://www.tindie.com/products/weird/isa-8-bit-ethernet-controller/

    8 bit ISA port Ethernet controller for IBM PC/XT machines, realtek chip on board.

    If any OCAUer tries this out, please let us know how you go.

    I still have a project in the back of my mind to make an image for a Raspberry Pi that turns it into a small NAS for DOS and Win9X machines. Keen to knock that out over Christmas maybe.
     
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  20. elvis

    elvis Old school old fool

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    Speaking of FMV, looks like a previously lost FMV game is getting a release. This thing looks like complete garbage, and I really want to play it! :)

    https://en.wikipedia.org/wiki/American_Hero_(video_game)

    [edit] Looks like the video can't embed, click through to get to it:

    VIDEO LINK

     
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