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Macintosh Portable self made SCSI cable 34-50 pins adapter
Posted by: ironborn65 on 2022-05-15 09:44:34
After the successful repair of my Portable (and here), I was able to boot from SCSI2SD connected to the external DB25, using the external +5V.
I do have the original Conner HD but if I plug it in, the Mac does hot even chime, so I left it apart.
Following this document http://myoldmac.net/FAQ/portable_scsi.htm I created my own cable adapter.
I took great care of testing all the pins and voltages. It all seems fine.
The mac boots, the yellow LED of the SCSI2Sd does the usual initial flash, a good symptom even if after a second or so, but the Portable is slow in powering the SCSI connector, then I have the flashing '?' Mac icon on the screen and the yellow LED in the SCSI2SD keeps flashing very feebly.
The card and the configuration are the same ones used for the successful boot from the DB25.
I'm questioning the termination, the scsi2sd configuration, and the proper pins mapping as found online.
Did anyone had a similar experience?

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Posted by: ironborn65 on 2022-05-16 13:02:00
Ok, "facepalm" ... again ... there was one wrong pin, despite my several tests, one was really wrong.
Now it works! My self-made SCSI 34 to 50 pin works perfectly and the +5V is extracted from the SCSI and fed into the SCSI2SD using the berg connector.
Thread closed 🙂
I did it all by myself 😀
bye bye

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Posted by: cheesestraws on 2022-05-16 13:12:14
Nicely done!
Posted by: ScutBoy on 2022-05-17 06:52:08
Nice work! It always feels good to get something like this figured out!
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