Thursday July 8, 2004

Hardware Hackery

Rich has a T-shirt that says

I Am a Professional.
Do Not Try This at Home.

Perhaps I should have worn that shirt this past Monday. :-)

We have a Powerbook 2400. The 2400 is a fairly old Mac laptop. It's a PowerMac but it can't run Mac OS X. It will be stuck on Mac OS 9 forever. Nevertheless, back in November of last year, we decided to upgrade it to a larger hard disk (it came with a 1.3 GB drive). We had recently upgraded the drives in our G3 Powerbooks so we had a pair of 12 GB hard drives just lying around. Why not swap one into the PB 2400?

Well, one reason "why not?" is that it's difficult to do. It turns out that the PB 2400 really has "no user-serviceable parts inside". Just getting inside is tricky. We finally found instructions on the web. The instructions were not encouraging.

The 2400 is indeed very scary on the inside. This procedure is definitely not for the faint of heart. However, even though its got a lot of screws, it doesn't require any forcing and bending of plastic or ribbon cables, which is more than I can say for some other PowerBooks, and everything just kind of comes in and out comfortably. If you've had experience taking moderately complex things apart before, this shouldn't be too bad.
OK, it shouldn't be too bad. How bad could it be?

You will need:
1. A grounding strap (don't be dumb about this)
7. A clean and uncluttered work surface

8. Lots of patience and organization

It is very, very, very important that you place every screw and part in such a way that you will know how to replace them. Don't even think about putting them all in a Dixie cup and figuring it out later. Take notes if you have to. Between 32 and 37 screws will come out, and they're many different sizes. I put them on the desk in order of extraction.

Rich did the actual take-apart. It requires two or three tiny-bladed Phillips head screwdrivers, very good light, a keen eye, and a lot of patience. It did not take a short time. He got the drive replaced and the PowerBook 2400 back together and... there were three or four screws left over.

We looked at each other. We rationalized. We dithered. We sighed.

Rich took the 2400 apart again. This time when he put it back together there was one screw left over. This time he said "No. One screw does not matter." So, we crossed our fingers, took deep breaths, and pressed the Power button.

It did not boot. Worse, it came up to a nasty little screen of nearly unreadable text (grey on darkgrey) that said we were in OpenFirmware. If you don't know what that means... you're better off for not knowing.

It turned out that Dumbo had made a mistake. (Dumbo is me when I do something so stupid I feel better referring to myself in the third person). Dumbo knew that the drive from the G3 had Mac OS X on it but... well,... in theory it had Mac OS 9 on it too and I just sort of thought the machine would boot the correct partition. I was worng [sic]. It seems I had gambled and lost. Now what?

Now we had a choice: go back inside the PowerBook or try to get it to boot from the hard drive. It wasn't much of a choice. Rich vetoed plan A. So, over the next month or so, on and off, when I had a spare tuit or two, I would try to get the 2400 to boot.

I asked a friend to return the external CD-ROM drive he had borrowed that works with a PB 2400 (the PB 2400 has a very, shall we say unusual, SCSI connector). I tried to boot from a CD. No dice. I tried a different CD. I asked friends for suggestions. Suggestions were supplied but not in any form I could readily use:

You should be able to boot into "SCSI Target Mode," wherein the 2400 operates like it is an external SCSI hard disk. Plug into some computer that supports SCSI and you can whack on the 2400's internal HD at will.

You need the right cable:

Apple HDI-30 SCSI Disk Adapter This adapter, model number M2539xx/A is specifically for SCSI Disk Mode, also known as HD Target Mode. It can be distinguished by its HDI-30 connector having 30 pins (5 rows of 6). ... When a 30-pin cable is plugged in, the 2400 automatically comes up as a target device.

The only issue is that you *should* set its target ID (SCSI ID) in a control panel before shutting down and inserting the 30-pin cable. Since you cannot do this, we don't know if a) it'll pick something useful, or b) it won't work at all.

Well, that was academically interesting...

So we put the 2400 on a shelf. Every now and then I would walk past it. Every so often we would discuss it (this usually led to one of those "discussions" that is a euphemism for a rousing, er, "Discussion". Occasionally, I would suggest that I would do the take-apart this time, but I wanted an assistant and moral support.

The PowerBook continued to sit on the shelf.

In recent months, we came up with a possible use for the PowerBook. But the PowerBook was still in suspended animation. Finally, this past Sunday, on a drive to the North Bay, we had another "rousing Discussion". We ended up promising each other that we would take the durn thing apart on Monday (a holiday and therefore a free slot on both our schedules). Amazingly, when Monday came, we still had momentum. We gathered PowerBook and screwdrivers and implements of destruction. I sat down at the kitchen table and started to take the PowerBook 2400 apart for the third time.

In the end, it was all pretty tame. I got the machine apart with only a little difficulty. One screw was "screwed" and had to be forcibly removed with a "tool of last resort", the aptly named "Screw-Out™ Damaged Screw Remover" (a most excellent tool; buy one for yourself). Rich helped when a second pair of hands was needed. When we got down to the drive Rich said "If we weren't so paranoid we'd try to load Mac OS 9 on that 12 GB drive." and I said "But we are." and swapped in the original 1.3GB drive.

Then I started reversing my steps, putting everything back. We couldn't find another screw to fit where Rich had forcibly removed the dotched one... but we made do (he shaved the sides flat and finished screwing it in with a pair of forceps :-) I needed help getting the various tiny ribbon cables reconnected — it turned out Rich was very good at that. I made one mistake with which screws went where; I had marked which screws were the "upper" and which the "lower" but didn't mark the location of the respective holes.

We even found a place for that one screw that was leftover last time.

Then... smoke test.


It's coming up! There's the startup screen.... the marching icons... the Finder!

It's back together. It runs.

Rich says next time we have a project like this, he's just going to hand me the screwdrivers and let me do it.

Hardware Hackery ( in category Computerware ) - posted at Thu, 08 Jul, 19:37 Pacific | «e»