68kMLA Classic Interface
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| jmacz journey | |
| Posted by: 3lectr1cPPC on 2025-06-05 12:22:43 Drop everything and recap that 840AV's logic board! The traces on those boards are tiny and seem to be very easily damaged by the cap goo. Lucky that yours is still functional pre-recap - that's a score. | |
Posted by: croissantking on 2025-06-05 12:24:10Drop everything and recap that 840AV's logic board! The traces on those boards are tiny and seem to be very easily damaged by the cap goo. Lucky that yours is still functional pre-recap - that's a score. Absolutely right - clock is ticking! | |
Posted by: jmacz on 2025-06-05 13:34:25A working 840AV is a great result. The fronts often look different between models as they transitioned from caddy CD-ROM drives to tray loading; and from auto-inject to manual inject floppy drives. I have the opposite to you. Oh interesting. Didn't realize there were variants for the 840AV. Yeah, this one has a tray loaded CDROM but didn't check out the floppy yet. Drop everything and recap that 840AV's logic board! The traces on those boards are tiny and seem to be very easily damaged by the cap goo. Lucky that yours is still functional pre-recap - that's a score. Absolutely right - clock is ticking! Yup, took the caps off last night and found leakage. The 840AV was a little flaky before I took the caps off. It seems to get to the question mark floppy screen about 2/3rds of the time (otherwise it stays with a black screen) so thought it was working. But after testing further, it's unable to boot (freezes on the happy mac screen). And sound seems to be dead (no chime but still get to the question mark screen). Hoping it's the caps. There's a bit of capacitor gunk on 2-3 chip legs but didn't look at that bad. No noticeable damage under the caps but we'll see. The two Power Macintoshes logic boards seem clean, no damage that I can see on first glance. Brittle plastics though... yuck. Haven't tried booting them. | |
Posted by: croissantking on 2025-06-05 14:09:53Oh interesting. Didn't realize there were variants for the 840AV. Yeah, this one has a tray loaded CDROM but didn't check out the floppy yet.Looks like a caddy loader to me, and a manual inject floppy. | |
Posted by: jmacz on 2025-06-05 23:57:44Looks like a caddy loader to me, and a manual inject floppy. Confirmed that it's a tray loader for the CD-ROM, but the floppy is indeed a manual inject floppy drive. | |
Posted by: croissantking on 2025-06-06 02:46:35Confirmed that it's a tray loader for the CD-ROM, but the floppy is indeed a manual inject floppy drive. Wait, so it has a tray loading CD-ROM with the wrong type of bezel?  Cause that is definitely the caddy loader bezel. The tray loader bezel has a larger opening, and has an eject button.  Sorry if my pedantry makes it feel like I’m questioning your observations as you obviously have the computer in front of you - I’m just going off a photo. I’m mostly just a bit curious. | |
Posted by: lobust on 2025-06-06 06:17:50Wait, so it has a tray loading CD-ROM with the wrong type of bezel? I didn't realise until working with mine that the 840av was sold with both tray and caddy loaders, so it would be potentially possible to make one out of two and have the bezels wrong. I'm 99% sure the tray loader will not pass through the opening of the caddy loader bezel... Edit: sorry I didn't notice that you posted exactly this same thing a few posts above! | |
| Posted by: jmacz on 2025-06-06 08:04:12 Yup, it does have a tray loader and indeed, someone has placed the wrong bezel on it. And yup, the caddy bezel will not work with the tray loading CD-ROM drive.  | |
Posted by: croissantking on 2025-06-07 01:58:25Yup, it does have a tray loader and indeed, someone has placed the wrong bezel on it. And yup, the caddy bezel will not work with the tray loading CD-ROM drive.I wonder how they got mixed up. Are you going to change the bezel, the drive, or just leave as is? | |
Posted by: jmacz on 2025-06-07 08:05:28I wonder how they got mixed up. Are you going to change the bezel, the drive, or just leave as is? I will need to check with the guy I got it from to see if he has another that it got accidentally swapped with. But barring that, I have the proper bezel on my Power Macintosh 8500 which I can copy and see if I can make a model of and then 3D print a new one. | |
Posted by: Daniël on 2025-06-07 08:28:55I will need to check with the guy I got it from to see if he has another that it got accidentally swapped with. But barring that, I have the proper bezel on my Power Macintosh 8500 which I can copy and see if I can make a model of and then 3D print a new one.There is a model available for a trayloader bezel that's pretty good, might save you some work 🙂 
3D Printable Bezels for Macintosh Quadra 800/840av, PowerMac 8100/8500/9500 by AlexIf you have a Quadra 8XX or PowerMac 8XXX/95XX, one or more of the drive bay bezels are probably broken off the front of your computer. Finding replacements these days isn’t easy or cheap, so I measured one of my few remaining good parts and whipped up some replacements. There are two bezels...
www.myminifactory.com
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Posted by: jmacz on 2025-06-07 08:54:21There is a model available for a trayloader bezel that's pretty good, might save you some work 🙂 Awesome, thanks! | |
Posted by: croissantking on 2025-06-07 10:57:43I will need to check with the guy I got it from to see if he has another that it got accidentally swapped with. But barring that, I have the proper bezel on my Power Macintosh 8500 which I can copy and see if I can make a model of and then 3D print a new one.If you don’t end up needing the old bezel, I’d be interesting in buying or trading something for it. I’m quite keen to put a caddy-loading drive in my 840AV. | |
Posted by: jmacz on 2025-06-07 11:34:39If you don’t end up needing the old bezel, I’d be interesting in buying or trading something for it. I’m quite keen to put a caddy-loading drive in my 840AV. Ok, I certainly don't need it. I'll give it a once over to see what condition it's in first and let you know (ie. make sure the plastic is in good shape with no cracks). | |
| Posted by: jmacz on 2025-06-07 22:45:45 Crazy how well evaporust works. That metal shield around the CD-ROM drive was covered in rust. This is after a few hours in evaporust.  The dark spots are the carbon residue after evaporust reacts with the rust. It comes off with scotchbrite. This liquid is non toxic, odorless, and safe. And best of all, it's reusable, you just filter it back into the bottle and it's good to for next time. | |
| Posted by: jmacz on 2025-06-08 16:01:06 Never assume anything until you've looked into it. Here's the battery bombed LC III. It seems to have been stored on its side so when the battery leaked, it ran across the logic board, all over the memory chips, onto the PSU, into the PSU, and out the other side.    Took the memory chips off and the VRAM socket off. Legs crumbled off the memory chips and some pads were gone.  But after cleaning it up...  Not too bad! 12 pads gone. There was also a lot of capacitor juice everywhere. Assuming the proprietary Apple chips are ok, might be saveable. Need to procure the memory chips, order some caps, and then will have to give this a try in a few weeks after other projects finish. The PSU looks like it might be ok as well (at least the insides). The PSU casing as well as the chassis shielding are going to suck in evaporust for a few days as it's pretty extensive. Maybe those can be salvaged as well. I guess we'll see. | |
| Posted by: jmacz on 2025-06-08 16:07:25 I've got capacitor gunk in the pink areas. I need to check traces in the cyan areas although visually it looks ok. And the red dots are lost pads. Not as bad as I thought it was going to be on first glance.  | |
| Posted by: obsolete on 2025-06-08 18:22:27 Careful with battery-bombed parts in Evapo-Rust. I soaked a Maxell-bombed SE/30 chassis in mine and it seems like something from the battery juice contaminated the Evapo-Rust. A very unsavory chemical reaction occurred; the solution turned dark and smelled awful. I had to toss the whole 3.5 gallon bucket. An expensive lesson. | |
Posted by: jmacz on 2025-06-08 18:40:01Careful with battery-bombed parts in Evapo-Rust. I soaked a Maxell-bombed SE/30 chassis in mine and it seems like something from the battery juice contaminated the Evapo-Rust. A very unsavory chemical reaction occurred; the solution turned dark and smelled awful. I had to toss the whole 3.5 gallon bucket. An expensive lesson. Hmm ok. I had scraped off a lot of it before going into the bath... but I just went to check and it is indeed dark, no smell though. Argh, oh well. Guess I need to toss it after this is done. Luckily I only used 1 gallon. | |
| Posted by: jmacz on 2025-06-08 19:04:44 On a second look, I think it's fine... it's still the usual yellow color, it's just there's rust particles which is making things cloudy. I usually pour the stuff back into the bottle through a filter. But in this case, since I did use it on a battery bombed chassis, I'm going to take it to the hazardous disposal center and buy a new 1 gallon bottle. | |
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