PowerBook external SCSI CD not working.

[Solvalou]

So I've been working on my PowerBook 500's and my 180c, managed to get them in a nice running condition.

Data transfering on these machines is nothing short of a bit of a pain but I should have the tools to do it.nor so I thought.

I have one of these "Media Vision" HDI to 25-pin SCSI adapters and I'm trying to run a SCSI CD-ROM drive from it, and all the laptops I try are all doing the same thing.

The two drives I have are an old Lacie one (blue case with a green light on the top) and an original Apple 300e. I know for a fact both work on my desktop computers but the 300e causes the PowerBook's to just boot to the disk question mark screen and the Lacie doesn't do or affect anything.

Changing the ID's does nothing so.om staring to wonder if the Media Vision adapter could be at fault. But if the 300e is anything to go by, it does seem that it is atleast communicating in some way to the SCSI bus.

I'm sure I know the ports are fine as I'm certain I remember using an external HD without issue (though I can't find it right now).

Is this a common issue? Probably missing something really obvious and stupid.

Oh and both have the second (unused) SCSI port terminated. 

Any help and guidance would be appreciated. Thanks in advance.

 

[sutekh]

Definitely sounds like a termination issue. Several potentially questions: How long is the cable (may need active termination). If using an active term, is anything powering it? Have you verified the jumpers on the CDRom are correct (e.g., parity, unit attention, etc.)? 

 

[Solvalou]

Definitely sounds like a termination issue. Several potentially questions: How long is the cable (may need active termination). If using an active term, is anything powering it? Have you verified the jumpers on the CDRom are correct (e.g., parity, unit attention, etc.)? 

Well there is only one cable going from the CD to the laptop which is a 50-25 pin Apple branded cable and it's probably about 20-30 CM long. That is in turn being converted from a 25-pin to an HDI connector.

I wouldn't know for certain how they are jumpered without opening them up, but since the drives work fine on my desktop machines, shouldn't it also be plug-n-play on the laptops?

I have used an active terminator on both drives for certain (has an LED on it too). I have one other which is just housed in a metal shell with no text on it (assumed passive). Both seem to have the same outcomes on both drives.

 

[sutekh]

I'd definitely crack them open to find out. SCSI controllers are not all created equally, and some are much more forgiving in my experience. For instance, I recently opened up an external SCSI CDRom drive that had been working on my XT but was behaving badly only my LCIII, to discover that it had an "enable term" jumper installed thereby negating the active term I'd installed at the end of the bus.

 

[Solvalou]

Well it had a jumper on "Term Power" on the 300e. Tried removing it and still the same outcome. Tried both passive and active terminators, various SCSI ID's and on different PowerBooks. All same old.

I can understand in your case not working on XT's, that's a completely different kind of beast, but one would think that if it works on desktops should work on PowerBook's since they speak the same language logically.

Also found and tried using my external SCSI HD. As remembered, it booted and saw that just fine. 

 

[douglasgb]

If you have the cables, try Powerbook - CD - ext HD.