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Mac Portable Issues with ZuluSCSI

mooseman

Member
My Mac Portable has been recapped and boots up fine from floppy or Floppy Emu. It's got a rebuilt lead-acid battery in it that's good as well.

I'm trying to get it to work with ZuluSCSI and no-go. With the ZuluSCSI plugged in nothing happens when I try to start up the machine: no lights on the card, no chime, everything's dead. As soon as I unplug the ZuluSCSI I get a chime and it boots. I'm using a 34-50 pin adapter from eBay, molex power connector is left disconnected.

Not sure what's going on here, seems like an insufficient power problem? All the guides I'm finding are for SCSI2SD and I'm not finding a lot of details on ZuluSCSI, but it should at least be powering up regardless of what's on the SD card. Anyone dealt with this, and am I missing anything obvious?

I've got the adapter mounted with the 34-pin connector pointing up relative to the top of the card, which I am 90% sure is correct. Thanks for any help.

IMG_1748.jpeg
 

mooseman

Member
To add, the ZuluSCSI seems fully functional: I powered it via USB, updated the firmware, and from the log file it appears to have loaded my image file correctly.
 

SuperSVGA

Well-known member
Which Portable do you have, the M5120 or the M5126?

Do you have a multimeter to check the voltages at the molex power connector of the adapter, with the ZuluSCSI disconnected?
 

mg.man

Well-known member
Ah, I see the ZuluSCSI does not have the BERG connector - so you'd need to jury-rig something. 🤔
 

Berenod

Well-known member
I don't believe the Portable supplies TERM POWER - which would power the ZuluSCSI. Have you tried supplying power via the molex connector?
It definitely doesn't have term power on the external DB25, whatever you stick in there needs power from somewhere else, the internal scsi is something special anyway...
 

Berenod

Well-known member
I'm using a 34-50 pin adapter from eBay, molex power connector is left disconnected.
Where did you get one of those? Seems to be hard to find (or stupid expensive for a totally passive thingy with twe connectors on a pcb)
 

Juror22

Well-known member
As stated, it will need the BERG connector installed, so that it has the power available to it.
Here is a writeup that is similar (using the ZuluSCSI's cousin, the SCSI2SD and a homemade cable) and that was a part of the magic combination - they need to be externally powered, sort-of.
Here is the Connector location on your board (from the picture that you posted above)
Bergman.png
hopefully, you had them ship the connector along with the ZuluSCSI, so that you can solder it on, which is what I did with mine. If not, maybe they (the folks you ordered from) can send you one for pretty cheap; but you will need one of the connectors installed on your board to make it functional in this application.
 

Juror22

Well-known member
The adapter provides power to the ZuluSCSI via the termination power on pin 26, supplied via the diode connected to +5V.
Good to know! I had no idea, given the separate power connector, but I can see the diode in the picture (on eBay). Good advice on checking the power a couple posts ago.
 
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