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  1. Stephen_Usher

    My Portable just blew it's (new) battery. (M5120)

    Indeed, 7.5V is the correct charging voltage. If you check on the label on the battery you'll see this listed. All I can suggest is that there's a fault in the battery generating an internal short, possibly buckled plates.
  2. Stephen_Usher

    Mac se/30 SCSI2SD version

    I've a v6 in an SE/30 and it's fine. Just don't turn on the SCSI2 stuff. As for the original poster's question about speed, no, the SE/30 won't take advantage of it. The NCR 53C80 maxes out at a theoretical 1.5MB/s but in reality is about 1.2MB/s.
  3. Stephen_Usher

    Macintosh Portable, what is R21 resistor value?

    From that image Q21 looks cooked. I had that on my machine when the +12V line got overloaded.
  4. Stephen_Usher

    SCSI problem.

    The SD2SCSI (v5.1) works in all my other classic Macs as it is, without any configuration changes and with the same SD card and filesystem, so it's unlikely to be an incompatibility. I've run out of Mac compatible SCSI drives now as they all seem to have died with age.
  5. Stephen_Usher

    SCSI problem.

    As previously stated the device I'm testing with works fine on another SE/30 and Mac Portable. It's a SD2SCSI and the filesystem was created on the other SE/30. The drive was just moved from one machine to the other. By one drive I thought you meant one drive connected at the time rather than a particular drive.
  6. Stephen_Usher

    SCSI problem.

    No, just the one.
  7. Stephen_Usher

    SCSI problem.

    I could try getting it off the board, I do have a hot air rework station, but any such work is risky, so I'd leave that as a last resort. I'd install a socket afterwards if I did remove it though.
  8. Stephen_Usher

    SCSI problem.

    System 7.0.8 reports the disk as unreadable and asks if you want to initialise it. Disk First Aid says "Bad Disk Name".
  9. Stephen_Usher

    SCSI problem.

    After finally getting around to looking at my second SE/30 and its SCSI problem I think I need a second opinion: The machine is fully recapped and other than the SCSI issue works perfectly. Symptoms: SCSI disks are seen but any filesystem found on the device gives an error "Invalid name". Initialisation hangs and then times out. I've buzzed out all the SCSI lines and the system data lines and they seem fine. Using an oscilloscope I can see data transfer on every SCSI data line. I'm using a known good SCSI device which works on other systems. All the PCB tracks look fine, as you can see from the attached image. So, I'm guessing that the issue is with a bad NCR53C80 SCSI chip?
  10. Stephen_Usher

    Portable / Powerbook SWIMs

    Yes, CMOS is less power hungry, but it also has a lower voltage for logic high and has a lower maximum current throughput. CMOS driving TTL/NMOS chips can cause them damage due to excessive power draw. Also the TTL chip can sometimes not see the logic '1' values. There are special CMOS chip types which can interface with TTL/NMOS chips.
  11. Stephen_Usher

    Portable / Powerbook SWIMs

    Could the desktop ones be NMOS and the laptop ones CMOS?
  12. Stephen_Usher

    SCSI2SSD for Macintosh Portable?

    Someone sells a Mac Portable SCSI to normal SCSI+Power adapter board+cable on eBay. Be careful though, the one I got had the Molex power connector incorrectly wired, with the +12V and +5V wires reversed, which killed two hard disks and an SCSI2SD card before I realised what was happening. https://www.ebay.com/itm/Macintosh-Portable-34-to-50-pin-SCSI-Hard-drive-Adapter/312973273392?hash=item48dea92930:g:Dp8AAOSwMsVXjEow
  13. Stephen_Usher

    Well Crap (SE/30)

    Well, WD-40 (or, Water Dispersant No. 40) is a reducing agent, designed to remove oxidation so as to allow engines to start after the high tension side became damp, so it makes sense that it would reduce the oxidation caused by the leakage, possibly redepositing copper.
  14. Stephen_Usher

    I've just got an SE/30 and need some help

    They will work with any switch, but only at 10Mbit. It merely depends upon how brain dead your network switch is. If it's a decent one then without being able to negotiate the connection it should default to 10Mbit, which is what the old 10BaseT hubs ran at. I had my SE/30 connected to a gigabit switch with no issues.
  15. Stephen_Usher

    I've just got an SE/30 and need some help

    You'd need a Mac with an ethernet interface running 7.5 to act as a bridge. I used an SE/30.