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  1. booboo

    LaserMaster CORP OFMD-01 LXPC-01 ISA SCSI

    Reviving this thread as here's a MCA version of this board (I think...) https://www.ebay.com/itm/175998978705
  2. booboo

    Osborne 1 screen flash

    We discuss the keyboard here: https://forum.vcfed.org/index.php?threads/osborne-keyboard-identification.1245068/ and here: https://forum.vcfed.org/index.php?threads/has-anyone-seen-an-osborne-keyboard-like-this.1244898/ It's a TEC keyboard likely, and can be taken apart but I haven't needed to.
  3. booboo

    Xerox 820-II revival!

    Would that be similar to the Kaypro, which used a WD parallel - ST212 controller board?
  4. booboo

    SUGGEST: Missing Caps in a Biostar M5VNB Socket 7 motherboard

    Did you melt the AT power connector (upper left of picture, on right side of connector)? or did someone else? Seems like this poor motherboards has had some difficult life. if you didn't touch the regulators in that region, all this may point to someone that tried to fix and failed on this board.
  5. booboo

    Do you order from small business online stores?

    Yes, I purchase from TexElect, ReActiveMicro, for speciality items. For components, my go to is Mouser (but I'm in Texas). I also buy components from Amazon, mainly larger quantities resistors, safety caps, etc. But for very critical capacitors (say low ESR electrolitics,) as well as chips...
  6. booboo

    IBM PC XT 5160 RAM Errors on Bank 0 - It's not RAM?

    Thank you for all the attention! No other ISA cards are on the system, I tried also a 16-bit VGA (that supports 8 bit systems) and wouldn't POST; and because RDR doesn't support VGA then I took it out. I'm heading out of town for work for a week, then thanksgiving is upon us. So don't rush...
  7. booboo

    IBM PC XT 5160 RAM Errors on Bank 0 - It's not RAM?

    Thank you. To your points: (1) Yes they are known good NEC 4164 -120 chips. Stolen from a six-pack board from a 5150 :). (2) Yes, I get the short-long-short beeps from RDR program.
  8. booboo

    IBM PC XT 5160 RAM Errors on Bank 0 - It's not RAM?

    Thanks, appreciate the video! Yeah, the issue here is that it's not a single (or even multiple) RAM chip failure. The entire bank 0 keeps failing in the testing, even replacing the entire bank 0 with known good chips. I need to perform the tests above from Modem7 but I suspect there's...
  9. booboo

    IBM NetVista A40 6578 Invalid BIOS

    Here are the BIOS update files and instructions.
  10. booboo

    IBM NetVista A40 6578 Invalid BIOS

    Try reviewing the Hardware Maintenance Manual : https://www.manualslib.com/download/75471/Ibm-Netvista-6058.html Are you sure your board doesn't have the jumper 12? Clear CMOS /Recovery? Seems the Vital Product Data is corrupted. Try these procedures: Vital product data Each computer has a...
  11. booboo

    IBM PC XT 5160 RAM Errors on Bank 0 - It's not RAM?

    The board came as-is to me, without history. So don't know how long it hasn't worked correctly I've actually been looking at the various options of the mem test: I removed all RAM and the error was same as the initial picture, *EXCEPT* that the error was on 0000:0000 I removed a single chip...
  12. booboo

    IBM PC XT 5160 RAM Errors on Bank 0 - It's not RAM?

    Thanks @modem7 for the quick review. It's always the same address, regardless of attempts or changing RAM. I've removed all RAM from banks 1, 2, and 3, only leaving bank 0. I do have the ability to burn a U18 ROM (I just burned the Rudd's code to run these diags), so love to get some code to...
  13. booboo

    IBM PC XT 5160 RAM Errors on Bank 0 - It's not RAM?

    I'm diagnosing this XT 5160 (64KB-256KB systemboard) that won't post. After replacing the IBM BIOS with Rudd's diag ROM I get a screen and it proceeds to test. It's failing in Bank 0 (2KB) with all chips except Parity shown bad bits. See screen... I've replaced with known good RAM and still...
  14. booboo

    Archive Corp Model 2060E QIC-02

    Before putting tapes in, I suggest you inspect the drive mechanism. On older drives the rubber rollers that move the tape can (and will) start to break down. They may be melted, hard as a rock, or brittle and flake off.
  15. booboo

    TRS-80 15 MEG 26-4156 repair

    That reminds me of the way my Kaypro 10 works. There's a parallel IO bus cable that does to a WD1002 board, and that has the MFM controller to the HDD. Of course all inside the Kaypro. Thanks for the photo!
  16. booboo

    Apple II Switch-A-Slot type card cage box

    That's what it does but requires you turn off power to the ][. So it's more about the convenience of not physically opening and moving boards in/out. I think that's what you mean though... even then the data lines might draw power from the powered down boards?
  17. booboo

    Apple II Switch-A-Slot type card cage box

    FYI: https://www.ebay.com/itm/126156077227
  18. booboo

    Has anyone seen an Osborne keyboard like this?

    When you say replacement, you meant by factory (either in or out of warranty)? I have seen no evidence that any 3rd parties sold these, but seem rather variations from factory.
  19. booboo

    IBM Proprinter XL Guide To Operations

    Don't have a link for the guide to operations, but if all else fails, there are hardcopy versions on eBay: https://www.ebay.com/itm/143664789332
  20. booboo

    IBM Proprinter XL Guide To Operations

    Technical reference is here: https://archive.org/details/proprinter-family-technical-reference-manual-opr/Proprinter%20Family%20Technical%20Reference-Manual/ includes the XL among others.