I think I know why the disk benchmark is so high - it's because I'd set the disk cache to 1.5MB which is the default for Mac OS 8.1 with 48MB of RAM, whereas before it was just 96kB. If I change the disk cache to 96kB I get: CPU:151%, FPU:217%, Disk:139%. This compares with PB1400/117/MacOS8.1/96kDiskCache=. CPU:123%, FPU:135%, Disk:87% and makes the PB1400 165% of the performance of a PowerMac6100/60, about as fast as a PowerMac 7500/100 (
@Phipli ;-) ).
So, onto the hinge cover, the ugly technique. Sorry about the detail! I have a hinge cover for the other PB1400, but I broke the back clips and I wanted to avoid doing that this time. I wasn't quite sure if it was the clips or the centre bit of the case that was the problem and spent a bit of time trying lever the hinge cover over it.
The real breakthrough came when I found that, in a similar way to the way the service manual tells you to lever up the cover from one end, I could get the cover to snap into place at one end (the left end in my case) and this left it rising diagonally. I could see then that the centre bit must be behind the cover, so that was OK. I found that by pressing various parts of the cover and also looking inside from the front of the powerbook, with the lid slightly open that the inside clip at the low end was clipped in; that nothing else seemed to be blocking it at that side; that the cover would flex down on the inside high end, and the very end of the outside, but didn't seem to move at the high-end, outside, clip.
This meant I could be pretty sure that it was the clip itself that wasn't going in. I was quite concerned that using my hands to press the cover into place would likely make it slip and snap a clip as I had done on the other PB1400. So I decide to use some large ('toothed'?) pliers because although it looks brutal, it's easier to apply a more controlled force thanks to the leverage.
I could open them wide enough to grasp the underside of the top casing and the top of the hinge, where the clip was. And with a reasonable, but not excessive amount of force it clipped into place.
If I was to do it again, I'd probably put some thin cloth between the jaws and the plastic to eliminate potential scuffing (I didn't notice any scuffing afterwards though).
The other thing to notice is this: Computer Architecture A Quantitive Approach 2nd Edition, is the perfect height for resting the folded back screen when unscrewing the hinge itself :-D !
Now, I'm putting the other PB1400 back together (which will be the 117 unit) and I'm trying to connect the trackpad cable - what a pain! The service manual seems to imply that fingers are just a few mm wide and can easily get in the gap at the top of the casing; whereas I'm fiddling with a small flat-head screwdriver going through the front between the top and bottom halves of the case, to lift up the catch on the PCB while fishing with a spudger going through the top gap to align the connector. Why, Apple? Why do you do this to your fans?!!?! They're on your side!!! ;-) !