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dchang

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  1. dchang

    Powerbook 180C Wont boot from SCSI

    I got it to boot off the external scsi drive. You have to set it in Control Panel -> Startup Disk and select your external drive. And then the next boot up it boots from the external drive.
  2. dchang

    Powerbook 140 scsi hard disk failure

    I found the Powerbook 140 and 170 Developers Note. It's a 30 pin cable.
  3. dchang

    Powerbook 140 scsi hard disk failure

    Hi Parrotgeek1, Yeah, I think a better strategy is replacing the SCSI drives with CF or SD flash drives. Something I'd like to do eventually. But I watched video online about HD repair and watched a guy remove the PCB and check continuity between PWR and GND pins (on the connectors) and then proceed to check continuity on the diodes. If I understand it correctly, if there isn't resistance between PWR and GND (and the multimeter beeps) then there's a short. Diodes protects against a reverse polarity charge. So if a diode gets burnt then a charge saturated the diode (shorting it). So by removing it, the technician was able to get the PCB working. That's what I think. Anyway, as mentioned, I'm not sure about the pinouts on these drives. So I don't know what I'm checking. Only Vcc/Vcc pins and GND/GND pins should show continuity (but I'm not sure which pin is which).
  4. dchang

    Powerbook 140 scsi hard disk failure

    Another thing, are there references to pinouts for these SCSI drives? I found this: http://vintagemacmuseum.com/reading-powerbook-2-5-scsi-hard-drives/ But it's confusing about the number of pins. The PB140 has got a 40 pin cable. 4 pins on the disk are not connected. So an adapter for 54 pins to 50 pins SCSI suggests otherwise. I've also got a PB165 but it's got a full width cable (50 pins). The cable (50 pin) fits the drive fine.
  5. Just a stab in the dark, I got a PB140 the other day (in an AS-IS basis) and surprisingly it works. But it won't boot from the hard drive. So I took it apart and poked around (after watching a few videos online). From what I can tell power is reaching the actuator arm and spindle (when I use a screwdriver to move the spindle in the centre) it seems to jump a bit (when connected with power). If I'm not mistaken, then that means that the PCB on the disk isn't sending commands to the disk? So the disk isn't spinning at startup. I'm trying to figure out if it's the PCB or the motor. If power is provided by way of the scsi connector (on the PCB), and power flows to the actuator arm (I'm assuming given my observation), can I assume that the PCB is receiving power and functioning? Is there any other indicator that a PCB is functioning? There is no indicator light on the PCB. By the way it's a Quantum Daytona 341s.
  6. dchang

    Powerbook 180C Wont boot from SCSI

    I have the same problem. What I've been able to deduce so far is, If the HDI30 connector that goes into the laptop has 29 pins (i.e. the pin on the bottom right is missing) then it's a non-disk mode cable connector. That one pin will set the computer in disk mode. So you want to use a cable with 29 pins. However, if you have a scsi dongle (with a dock/scsi switch on it), then dock on means that the laptop will detect that one pin (i.e. disk mode will be set). So you want the dongle to be set for scsi. If you look in MacOS, scsi probe app, you'll see the CPU is set as scsi device #7 (highest priority) and scsi device #0 (is your internal scsi drive). So on my scsi zip disk I can set it to scsi #6 or #5 (no conflict with the cpu and internal drive). Also my zip disk has termination set on as well. So I've read a bunch of stuff and I tried a few but nothing works so far. To boot scsi device #5 for instance, you have to press keys SHIFT+Option+Command+5+Del during the startup. This failed for me. But seems false considering that you used to boot fine. I read that the system will boot the internal disk if it has a boot partition. You need to remove it so that it can boot from an alternate device. This seems false considering you used to boot fine. But question to confirm (you have a System folder in both internal and external disk)?
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