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  1. maxtherabbit

    Mid Atlantic NCR System 3300 or PC486 MCA BUS System

    Looking for any NCR microchannel system, located in Richmond VA willing to drive up to 100mi or pay shipping. Let me know what you've got!
  2. maxtherabbit

    486 Motherboard with abysmal ISA performance

    I've got a pretty neat 486 board here. Built in 1991, it uses a Zymos POACH chipset (designed for 286 systems) grafted to a 486 processor and cache with the help of a bunch of PAL/GALs and discreet logic. My issue with it is that despite using an ET4000AX card which will manage >4MB/sec on a...
  3. maxtherabbit

    Mid Atlantic Reproduction IBM EGA Memory Upgrade Board (6480099XM)

    This board was designed right here on VCFED by a user named abotj. I built one and it served me well for several years until I found a genuine IBM part to replace it. Guaranteed 100% tested and working. Asking $70 OBO shipped in the continental US.
  4. maxtherabbit

    New 5150/5154 Acquisition

    Bit of a sad story - my best friend's uncle died recently. He was formerly a technician at IBM working on big iron. His personal system was this 5150 that he had apparently upgraded over the years and I have now inherited it. The system was configured as follows: Hercules Color Card (pretty...
  5. maxtherabbit

    SIP bussed resistor array with common pin centered

    I have a Mitsubishi floppy drive which used a SIP terminator that is a bussed resistor network, but the common is the center pin. All modern bussed resistor arrays seem to have the common as pin 1. Is there a different name for this type of configuration or are these just no longer made that way?
  6. maxtherabbit

    30x Hard Sectored 8" disks

    not my listing, but these don't come up often so I figured someone here might be interested https://www.ebay.com/itm/Lot-of-30x-blank-ATHANA-8-Floppy-disks-NEW-unused-Model-47-0911-for-Wang-SS-SD/313418488383
  7. maxtherabbit

    Flyback Transformer for the IBM 5151 - part # 74730102538

    These are NOS from 1992. Aftermarket, but I tested one in my 5151 and they work fine. I have 4 available. Asking $15 shipped for one in the CONUS.
  8. maxtherabbit

    What's wrong with my 5151?

    First start it looks perfect, after running for anywhere from 30 seconds to a few minutes the horizontal geometry goes cattywampus and the raster starts quivering. Please take a look at the youtube video. I've tried: full recap deoxit on all pots and the horizontal linearity adjustable inductor...
  9. maxtherabbit

    What's wrong with my 5150?

    delete please
  10. maxtherabbit

    Disk Caching - EMS vs XMS

    So under 100% equal conditions, EMS would always be faster since it doesn't require the memory contents to be copied to conventional before they can be read by DOS. But what about the somewhat uncommon case of EMS which is limited to 8-bit memory accesses to the page frame? (Due to the LA lines...
  11. maxtherabbit

    IBM EGA with IBM Expansion Board

    Fully populated with 256kB of DRAM. Condition is pristine, almost brand new looking. Tested and guaranteed to work 100%. Original IBM expansion card, not a repro. Asking $150 shipped in the continental US
  12. maxtherabbit

    Depinning a crimp-type D-Sub

    Is it possible to non-destructively depin a D-sub connector? I'm referring to the type where you crimp the contacts onto the wires and shove them into holes on the back of the d-sub. Is there a way to get them back out?
  13. maxtherabbit

    Lo Tech 2MB EMS card

    asking price is $65 shipped in the continental US card was assembled by me, if you doubt my soldering chops feel free to utilize the high resolution photo to inspect my joints ;) I've been using the card for a year or so, it is thoroughly tested and guaranteed to work
  14. maxtherabbit

    Documentation for Alps DFL413C02B

    I'm looking for schematics or technical documentation of any kind for the Alps DFL413C02B 720k HH 3.5" floppy drive. This drive was used in the External diskette drive part 4865 as well as the 5140 convertible and also I believe the PS/2 model 30, possibly late ATs as well. Thanks in advance
  15. maxtherabbit

    WTB IBM 4865 External 3.5" 720k floppy drive

    Either version is fine, as long as it works
  16. maxtherabbit

    How to restart the floppy service in Windows NT 3.51

    I'm trying to be able to adjust the FDD configuration parameters in NT. They are read from the registry by the floppy driver at startup. The floppy driver must be run as a system service in order to provide drive letters for the disk drives. If I change the configuration data in the registry...
  17. maxtherabbit

    IBM half height mounting brackets

    ISO the IBM brackets for mounting half height drives in a PC/XT, specifically the plate that locks the drive to the case
  18. maxtherabbit

    PC-DOS 3.2 for 5150

    Thinking about downgrading my 5150 to DOS 3.2 to save a few more kB of conventional. Any reason not to? Looks like all of the changes in 3.3 aren't really relevant to my configuration anyway - am I missing anything? Is there any significant amount of software that would balk at a DOS version sub...
  19. maxtherabbit

    VGA BIOS at other than C000 (E000!)

    I have recently acquired a very interesting 486 motherboard based on the Zymos POACH chipset. That's right, the 286 chipset. It has a crapload of PALs and glue logic to handle the 32bit DRAM and cache, resulting in a full AT footprint. The 1990 AMI BIOS (pre color BIOS) only offers 2 extra...
  20. maxtherabbit

    RTC Stopped Ticking on my 286 clone board when power is off

    No, the battery is not dead. When the power is on, the RTC keeps good time (tested with checkit). When the power is off, the clock just freezes and doesn't advance. CMOS settings are never lost. I realize that these are the exact symptoms of a weak battery, but the 4xAA external battery pack...