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Thread: Well, this is just unfortunate

  1. #1

    Default Well, this is just unfortunate

    I was planning to do my great big grand reveal of a fashionably working AT&T 6300, all with it's original pristine MFM drive, the keyboard and the original installation of MS-DOS, but nooooooo, the CRT had to bust because of a shipping issue! Leaving the machine itself aside, I just had to find a working VGA card for the special doohickey it is with it's proprietary video board. And I made sure I did not fry anything by disabling both the onboard video jumper setting, and the W1 jumper that is present on the P8 video card.

    So, to cut to the chase, nothing I try to shove in it works! I've tried the VGA Wonder XL card, I've tried the Speedstar 24X with the BIOS access jumper toggled as "8-bit", I even wasted green leaves on a Paradise VGA Plus 16 just to see if flipping all the switches down (which is recommended for getting these cards to work on an IBM XT) would make video show on the damn thing.

    For every card I tried, it either locks up the machine on POST with nothing to show, or for the Speedstar, it just cheeses it by having the machine working but with no video to be shown at all. And I wonder...

    ...do these issues have any relations to how the mainboard simulates the 8088 BIU wrong? Something about wrong data being received and sent forcing the machine to lock up? All I can feel now is anger and rage building up from the machine at this point being nothing but a dud until I get the CRT fixed. Or can it just be simply a jumper issue with ROM not being mapped in the correct spot? I can post the mainboard jumpers if any of you would like to see...

    By the way: the special CRT's also a color CRT, so I really have to be careful with these things!
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  2. #2
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    Actually, if you're capable of making a cable and have an older VGA monitor (capable of 640x480 60Hz), you don't need to disable the video card in the 6300:

    http://www.olivettim24.hadesnet.org/..._converter.pdf

    The trick to getting a VGA card to work is to disable the onboard one--on mine, it was done by pulling a socketed PAL. Set the motherboard switches to "none" for display and use a decent 9-bit capable VGA card. I think I used a Tsenglabs 4000-based one.

  3. #3
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    Do you want to buy a whole new (non-working) 6300? I have the monitor (amber I think), keyboard and system itself and I think all it needs is a working PSU (or the one in there fixed).

    IBM 5160 - 360k, 1.44Mb Floppies, NEC V20, 8087-3, 45MB MFM Hard Drive, Vega 7 Graphics, IBM 5154 Monitor running MS-DOS 5.00
    IBM PCJr Model 48360 640kb RAM, NEC V20,, jrIDE Side Cart, 360kb Floppy drives running MS-DOS 5.00
    Evergreen Am5x86-133 64Mb Ram, 8gb HDD, SB16 in a modified ATX case running IBM PC-DOS 7.10

  4. #4

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    No thanks on the CRT offers, all it just needs I think is a capacitor soldered on. When I turn on the CRT, it flashes green for a second, then the light turns off; The CRT then makes a whining noise. Jiggling the thing around, it looks like a small part has fallen off, not too big, maybe part of the flyback? If it's totally capable of reassembly, and the circuit boards haven't broke, I'll be fine.

    Meanwhile, I'm still investigating why the Paradise VGA Plus 16 will just never work-- I've tried it in every different slot, but not WITHOUT the MFM card inserted; could it perhaps be mapping itself into a conflicting space with the MFM option ROM? I've also seen comments that the 14.318MHz oscillator circuit works differently on this machine, and therefore cards like early Sound Blasters would require some little hackarounds and wiremods, although that claim mainly comes from Lord_Nightmare himself. Going to reinstate the point that the "display" switch on the mainboard is set off, and the P8 video card is jumpered to be disabled. There's also a "scroll speed" jumper which some Olivetti manuals call it "nonstandard video card", oddly enough.
    Last edited by Kazblox; September 14th, 2017 at 06:06 PM.
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  5. #5

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    Well, I'm all out of ideas for now while I prepare for opening the CRT, the Paradise VGA Plus 16 still shows nothing with the correct switches, nor a post screen when the WD1002 is removed. Onboard video is still disabled, of course. There's apparently POST debug output that is sent through the parallel port, but you have to get a LED reader to read the codes. Seems like it's just simple character output though, is there a program (any OS is fine) that lets you easily read these without such a board?
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  6. #6

    Default Victory at last... to be continued

    Hi VCFED, I'd like you to meet my AT&T 6300! 6300, I'd like you to meet the fellow folks at VCFED! Say hi to each other! Tseng ET4000 rocks!

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    Cool!
    Bobby.

    (Looking for Olivetti M24/AT&T 6300 Keyboard - but I'm in AUS!)

  8. #8

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    Unfortunately, the drive is either dirty, actually 1.2M, or the disk drive jumpers are set wrong. DOS refuses to read my 360K formatted disk, which is just a tiny MS-DOS 6.22 disk in it. The BIOS also marks drive A as "Not Ready" too. Anyone know how to maneuver the drive bays on this thing without breaking any vital parts?
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  9. #9
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    Might be a faulty cable.
    Thomas Byers (DRI)- "You'll have a million people using the A> [MS-DOS prompt] forever. You'll have five million using [nongraphic] menu systems such as Topview, Concurrent PC-DOS, Desq, and those types. But there'll be 50 to 100 million using the iconic-based interfaces."

  10. #10
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    Could also be a mistaken drive select jumper.

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