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  1. M

    Cromemco 64KZ-II legend rev B schematics needed

    Ah, that's what that logo represents, the upside-down triangle with a 'D' in each corner. I have a Rev E board here with that delay line at IC19; a Rev D board has a version from Belfuse, a somewhat better known supplier of these chips, labelled 0447-0200-78 date code 8225 (curious, since the...
  2. M

    Vector Graphic Vector 4 restoration

    So do you have a good key?
  3. M

    PET reset switch circuit with a condensator for pulling the diagnostics line down

    I made one of these for my first PET but unfortunately I sold that one and don't have any notes; ISTR that it was a little simpler than what's proposed so far though, but I could be wrong. On my later PETs I used some dual-pole buttons that could have the trip point adjusted independently (they...
  4. M

    4k EPROM recommendation for PET 4032 option socket

    Indeed; I *think* I've also seen a Hitachi version of a 24-pin 64K 2364-compatible EPROM, but I've never been able to find it again, so it's probably just another symptom of my failing memory ;-) Philips also makes a 24-pin 64K EPROM (27HC641) but its pinout doesn't match either the 2564 types...
  5. M

    Commodore pet flickering screen

    The connector on the video board is notorious for intermittent contact, as is the main power connector on the PET pcb and all the IC sockets.
  6. M

    Is there interest for another SD card disk emulator for IEEE-488 or IEC interfaces?

    IMO an edge connector pass-through would be more flexible (and also cheaper) than an IEEE version. If connecting another device or devices is an issue then presumably the user already has a PET to IEEE cable for that; if your pass-through were IEEE out then they'd probably need to also buy an...
  7. M

    4k EPROM recommendation for PET 4032 option socket

    ... and you can have two different images in the same chip, selectable with pin 21. Another compatible chip despite being 28 pins is the versatile TI 2564 which can replace those non-JEDEC ROMs & EPROMS from 8 to 64Kb; the extra 4 pins are just used for programming & extra chip selects. And of...
  8. M

    Use 3.5 drive as 5.25

    Thanks, Chuck; guess I'll have to set up a 5.25" system.
  9. M

    Finally, after a bunch of years of waiting and searching I got one!

    Welcome to the Cromemco community! There's lots of documentation and system software available, as well as technical expertise, so you should have lots of fun. The CS-1 is one of the smaller Cromemco boxes; a little cramped and awkward to work on and as Roger mentioned quite noisy, but a nice...
  10. M

    Use 3.5 drive as 5.25

    What do driver.sys and drivparm effectively do? I assumed that one or the other could be used to override whatever the BIOS assumed but apparently there's more to it...
  11. M

    Use 3.5 drive as 5.25

    I'm not sure the source of the disk is important; the question is how to read a 360K 40 track 9 SPT MS-DOS format disk on a PC. It could just as well come from another PC.
  12. M

    Cromemco on google forums

    Should be, but I don't see any request; don't know where they're going, but not to me ;-) I wonder if Marcus isn't getting them either. DM me with your email address and I'll get you checked in. Once you're a member you'll have to separately request access to the Github repository from Marcus...
  13. M

    Cromemco on google forums

    You didn't say where you sent the request ? m
  14. M

    Cromemco on google forums

    Where did you send the request? m
  15. M

    imi 5012-H

    I think it's probably not feasible to read the drive on another system; the interface is completely different from ST506 or IDE and the format of the data on the disk will probably also be incompatible. Do you actually have a Synclavier working with that drive? If so, is there no way to export...
  16. M

    What ROM type?

    Dwight is probably talking about JEDEC standard EPROMs like the 2732; the TI 2532 is pretty well compatible with the 2332s used in most PETs, although not always with ones used in disk drives etc. Oddly enough, even the 28-pin 2564 is pin-compatible with a couple of jumpers. Here's a datasheet...
  17. M

    Use 3.5 drive as 5.25

    Thanks everyone for the replies. On one end is a PC that only has an FPC 3.5" floppy, so no 5.25 interface or BIOS option; on the other end is an S-100 Cromemco system which has the ability to read & write MS-DOS format 5.25" floppies but no 3.5" DD or HD (unless emulating an 8" drive with a...
  18. M

    Whats more common on the original PET 2001-8 a 6550 RAM board or a 2114 RAM board?

    FWIW all the static RAM 2001s I own and have seen used 6540s and 6550s
  19. M

    Use 3.5 drive as 5.25

    Is it possible to use a 3.5HD drive and pretend to MS-DOS or Windows that it is a 5.25DD drive, i.e. format and R/W a 3.5"DD disk with 40 tracks and 9 x 512 byte sectors ? I've played with DRIVER.SYS and DRIVPARM but no success... ;-( Thanks, mike
  20. M

    imi 5012-H

    I'm not aware of any PC controllers for the IMI interface; they predate the PC a bit and AFAIK they were used in Apple and Cromemco computers with Corvus and Cromemco controllers I do have a couple of 5007 drives and controllers, but the controller cards are S-100 Cromemco WDI-IIs, and even if...