• Hello, Guest! Welcome back, and be sure to check out this post for more info about the recent service interruption and migration.

Recent content by ymk

  1. Y

    Missing SE/30 SCSI Controller Chip

    Right. SCSI 1/2 are collections of standards and no device implements all of them. Trying to improve the I/O performance of a 16MHz SE/30 is probably a lost cause. JDW benchmarked SE/30 disk performance, showing significant gains with 030 and 040 accelerators. Timing the duplication of a...
  2. Y

    Annoying coil whine coming from Powerbook 100

    I'd still go with a conformal coating or lacquer over hot glue. It will penetrate better, trap less heat and won't soften when warm. I don't see a reason why it wouldn't be permanent.
  3. Y

    Annoying coil whine coming from Powerbook 100

    If you can identify the whining coil, conformal coating may silence it.
  4. Y

    Quadra/Centris 650 -- boot from external SCSI

    Remove the thing that's different.
  5. Y

    has anyone seen this before?

    Make sure the heat pipe hasn't failed.
  6. Y

    New puzzle game for 68k macs

    Neat game. What did you write it in?
  7. Y

    Which size Hard Disk Jumper Caps do I need?

    Sounds like they might be 1.27mm or 0.05" pitch.
  8. Y

    New puzzle game for 68k macs

    Very nice! I've been using THINK C 5 on a Centris 610. The 1152x870 display is easy to work with and compile times are reasonable. I test on monochrome Macs via LocalTalk, but I wouldn't want to develop on them. Here's something from 1995:
  9. Y

    Macintosh Classic stalls booting when anything is plugged into the SCSI bus

    I think a Classic PCB is in development. I don't blame you for setting it aside. I've got several logic board puzzles in storage, but too many better things to work on.
  10. Y

    Macintosh Classic stalls booting when anything is plugged into the SCSI bus

    Wild guess, one of the higher address lines? Eliminating the SCSI chip as a potential cause is still progress.
  11. Y

    Macintosh Classic stalls booting when anything is plugged into the SCSI bus

    Maybe the data lines? I'd swap the chip at this point. Mouser has the Z53C8003VSG. I don't know if it's compatible.
  12. Y

    Macintosh Classic stalls booting when anything is plugged into the SCSI bus

    I checked my board and SCSI controller pin 18 doesn't run to 68000 pin 8. It does run to pin 54 of the BBU. I mixed up the /LDS and /LDS' labels:
  13. Y

    Macintosh Classic stalls booting when anything is plugged into the SCSI bus

    Those are low, but I doubt they're causing a problem. Here are the lines on the SCSI controller that reach other ICs. The ones in cyan go to the CPU. I couldn't find any other reference to /IRQ in the schematic. I did trace it to pin 14 of UI6 (which I also couldn't find in there) on a spare...
  14. Y

    Macintosh Classic stalls booting when anything is plugged into the SCSI bus

    I'll check the schematics later. What do your +5V and +12V rails measure with that hard drive attached?
  15. Y

    Macintosh Classic stalls booting when anything is plugged into the SCSI bus

    Those voltages look OK and show the bus is idle. Check the pins of the controller for electrolyte and corrosion. The nearby rail caps often leak on to it. Swapping or reflowing the SCSI controller is what I'd try next.
Top