luRaichu’s 68k spelunking

[luRaichu]

I thought it would be a good idea to start a thread for my own vintage Mac adventures, which I hope will include a PB 180 in the future (although that seems slim now).

I’m currently still working on my trash-to-treasure LC, trying to revive the internal SCSI hard drive. It doesn’t mount, (it’s detected by SCSI probe) and SCSI director gives some scary news:

I did carefully open the drive soon after it failed last Summer, it looked good internally to me. In this photo I have the parity jumper removed so maybe that’s it??

 

[luRaichu]

Okay, turns out the drive was suffering from the all-too-common "sticky bumper" issue. I cleaned up what was left of the rubber bumpers and I'm looking for a good replacement. I've heard of people using electrical tape, but I'm hesitant cause I've seen how electrical tape can unravel... I guess I'll put it on and see what happens.

 

[rickrob]

I saw a video where PVC aquarium tubing was used to replace the bumpers
Home Depot has some tubing, might find a match there

Clear PVC tubing

 

[3lectr1cPPC]

I do the cheap way and just stick some tape over the bumpers. Probably should do something more proper or that rubber might become an issue when it fully goo-ifies and starts travelling within the drive...

 

[luRaichu]

I messed around with the internals of the drive a bit more. After removing the bumper on the magnet it was able to boot the old OS but it froze on the wallpaper/top bar, then on the next attempt it showed a happy Mac followed by a floppy disk (If there any cool, unarchived apps/drivers/games they're gone now). I wrapped the bare brass posts in electrical tape to build up a new bumper, and attempted to reformat. I had a problem where SCSI Director would fail on "Initializing" but I kept trying over and over, doing different things, and eventually got it to mount. We'll see if it mounts tomorrow...

I do the cheap way and just stick some tape over the bumpers. Probably should do something more proper or that rubber might become an issue when it fully goo-ifies and starts travelling within the drive...

That's a ghetto band-aid fix and will eventually result in disaster if you don't take precaution to replace those nasty bumpers soon. Mine were super goopy and got on the magnets, freezing the heads in place. Like that person said earlier you can use aquarium PVC tubing, I'd do that if but for now I'm sticking with electrical tape since that's what I got at home.

 

[3lectr1cPPC]

Agreed. the only drive I've successfully fixed anyway was a Conner laptop drive, and the way the bumper was made made it impossible to access to replace IIRC. It was a weird design, but also not one I worry will cause problems from further melting. I do need to invest in some electrical tape though. I'd think that there would be something you could soak it in to make it now come apart, if you did it right.

 

[luRaichu]

I'd think that there would be something you could soak it in to make it now come apart, if you did it right.

Funny you mention that. I used something called "TakeOff 'Professional' Adhesive Remover" to exfiltrate the gooified bumpers from the drive. It makes the goop a little less viscous so you can wipe it off with Q-Tips and TP. Goo Gone might work as well.

 

[luRaichu]

After the internal hard drive was formatted by SCSI Director I tried to make it my boot disk by copying a System Folder to it, but then I kept getting weird errors and after that it wouldn't mount anymore. So this time I decided to try Silverlining. I went through with the Format process and got to "Test & Map Bad Sectors". At first it couldn't write some blocks but I let it run until Pass 8, thinking the disk checks are on an infinite loop. I clicked Exit then went to Initialize, blah blah blah, and it made something that mounts again. Then I copied a smaller System Folder to the hard drive and restarted, and it just displays a window in the bottom-right corner showing that the Silverlining driver is installed without giving me a happy Mac. So then I flip the power switch off, disconnect the internal HD power cable and plug it back in after booting to my BlueSCSI. After that it can't mount or read/write to the disk properly until I re-initialize in Silverlining. I did the same thing twice until it couldn't initialize, so I went to Format and right now it's still testing sectors. Do I click exit or is it supposed to finish after a certain amount of passes?

 

[luRaichu]

Yeah, the drive don't wanna initialize no more. On a side note I've noticed the drive makes a faint buzzing noise when the heads are near the edge of the platter. And according to Silverlining most read errors occur in sectors <20000 I think. There's one bad sector but Silverlining won't let me mark it as bad, it always errors out.
This has been a frustrating ordeal. If I had an automatic firearm I probably would've shot out that spinning disk of s#!t already! Might've solved the problem

 

[luRaichu]

Today I got the drive to sorta work. I see the platter has tiny white specks near the edge which might've been caused by contamination from my surgery. I tried to get them off with a toothpick but no use.
I screwed everything back together tightly and this time the drive was willing to cooperate. However while doing short tests in Silverlining I noticed the first 5% of disk fails read checks. My redneck fix was to make a 1MB dummy partition, unmounted by default, and to create a good partition big as the rest of the disk. I actually had to leave a little bit of free space so it would initialize properly.
If you're working with slightly bodgy storage devices like this, I'd recommend Silverlining 5.8.3, it worked in this case and if you have bad sectors it's supposed to allow you to map them out. Map-Out never worked on this mechanical Quantum disk but it might help others. Anyways, now I can finally enjoy the amazing clicking sounds that eminate from the disk when the voice coil makes the heads jump around. I think these mechanical drives are as much a part of the retro experience as anything else.

 

[luRaichu]

Well, recently the Quantum drive just decided to give up for the second time. I'll launch Netscape on a particularly unlucky day, and the whole computer will freeze (except for the mouse because that's handled in ROM) and after a couple minutes I'll decide to just switch off the PSU. After reboot the drive'll do it's clickity-click-clicking and flash a happy Mac but THEN switch to the next bootable drive (BlueSCSI), from there it'll tell me this Macintosh disk is unreadable and asks me to Initialize. After initialization it'll work again. But as I said this is already my second time going through this, should I still use the Quantum drive?

 

[rickrob]

I would replace it, seems like it is not going to be reliable

 

[3lectr1cPPC]

It’s probably got the sticky rubber bumper issue. Judging by how hard it’s trying to live, I think it could be worth repairing it instead of giving up on it. I believe that they can be fairly reliable if that bumper is taken care of. Depends on what model drive on how the fix works. I always forget which is which (ELS of LPS), but one of the two has a bumper under the platters (and one in the head mech too I think?) and the other has it just in the head mechanism where it’s accessible.
I believe even for the under-platter variety, you can install a shim in to prevent the head from contacting it and fix those.
I need to get my information straight and then make a guide on my website breaking down what to do for each drive…

 

[volvo242gt]

It’s probably got the sticky rubber bumper issue. Judging by how hard it’s trying to live, I think it could be worth repairing it instead of giving up on it. I believe that they can be fairly reliable if that bumper is taken care of. Depends on what model drive on how the fix works. I always forget which is which (ELS of LPS), but one of the two has a bumper under the platters (and one in the head mech too I think?) and the other has it just in the head mechanism where it’s accessible.
I believe even for the under-platter variety, you can install a shim in to prevent the head from contacting it and fix those.
I need to get my information straight and then make a guide on my website breaking down what to do for each drive…

The LP and LPS series drives with the three ribbon cables look to only have the rubber bumpers in the head mechanism. Tore down the LP52S I got from RedJacketPress, and only saw them there. So, that would mean that the drives that have one ribbon cable probably have the under platter bumper. So, everything from the ELS drives through the later LPS drives, into the Maverick and Fireball drives...

 

[luRaichu]

It’s probably got the sticky rubber bumper issue. Judging by how hard it’s trying to live, I think it could be worth repairing it instead of giving up on it. I believe that they can be fairly reliable if that bumper is taken care of.

I think the replacement bumpers are fairly good. What I'm worried about is the fact the first 5% of disk fails read checks. I've mitigated the issue by making a throwaway partition, but it still causes the drive to always fail Disk First Aid and you can't use Find File either. As I've pointed out, there's visible, bad spots near the edge of platter.

OR perhaps it is (hypothetically) a bumper issue because my bumper isn't beefy enough and it tries to read invalid sections of disk. Also I haven't put a bumper on the post that stops the heads from falling off the platter because the bare brass post still stops it anyways. Maybe I should. What's the exact thickness of these things?

 

[3lectr1cPPC]

Of, I thought you hadn’t replaced them yet. Nevermind.