Jump to content

Stephen_Usher

6502
  • Content Count

    92
  • Joined

  • Last visited

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. 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
  2. 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.
  3. 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.
  4. 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.
  5. Stephen_Usher

    Macintosh Portable inconsistent 5V+

    DO NOT EVER POWER WITH ONLY THE CHARGER! (a) The charger can't produce enough power. (b) Without the battery the power subsystem is unstable and generate high voltages on the +5V line, frying chips. The power sub-system is not failsafe. Only ever start the machine using a properly charged battery or using a regulated (important) 6V power supply via the battery connectors. There really should be an FAQ at the top of this area with this information in bold at the top. Preferably with flashing lights and klaxons.
  6. Stephen_Usher

    Macintosh Portable Troubleshooting

    This should do according to the schematic Mouser No: 844-IRF9Z30PBF Mfr. No: IRF9Z30PBF Mfr.: Vishay Semiconductors You can see the designation on Q14 and Q15 in the picture posted above.
  7. Stephen_Usher

    Macintosh Portable Troubleshooting

    I'm guessing that you are in the USA, in which case Mouser should have them.
  8. Stephen_Usher

    Macintosh Portable: Twitching in its sleep.

    I'm afraid not. Without starting to remove chips one by one, which is dangerous in of itself, until I find the one pulling the line up there's not much more I can do. Given that the machine is not going to be powered up and sleeping much (it's going to be mostly packed away with all batteries removed) and only shown as a curiosity really, the 10K pull-up work-around is "good enough". If the machine were to be spending a significant amount of time asleep or shutdown I would consider it more of a priority due to the increased risk.
  9. Also, trying to run with a bad battery is a potential disaster for the Portable as the power sub-system doesn't fail safe and can send high voltage down the +5V line killing chips.
  10. Stephen_Usher

    Macintosh Portable Troubleshooting

    Q16 does control the +5V line, as can be seen in the circuit schematic that techknight posted above. Looks like at some point there might have been a short circuit on the machine and it overheated the component. The IR9230 components are cheap and relatively easy to remove with a hot air reworking station so if you can I would change it.
  11. Stephen_Usher

    Macintosh Portable Troubleshooting

    Sounds like something with a lot of electronics experience, both analogue and digital, might have to work on then.
  12. Stephen_Usher

    Macintosh Portable Troubleshooting

    Electronically, what does it actually do?
  13. Stephen_Usher

    Macintosh Portable Troubleshooting

    Those voltages are definitely low relative to my machine. Do they change when you try to wake the machine up?
  14. Stephen_Usher

    Macintosh Portable Troubleshooting

    For the 5V you can clip the negative probe from your voltmeter to any GND point and then put your positive probe on pin 3 of MOSFET Q4 (at the top right as you look from the front of the PCB. This is always on so should show +5V even if the machine is shut down. Keep monitoring the voltage as you press a key on the keyboard to start the machine up. The voltage shouldn't drop. For the +12V line, in the same area you will find the two Sony sound chips. Pin 13 on either of these is on the 12V line.
  15. Stephen_Usher

    Macintosh Portable: Twitching in its sleep.

    Yeah, it's a non-backlit. From what I remember those are a set of three 244s. 244 buffer chips are notorious for going faulty.
×