68kMLA Classic Interface
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| Macintosh Portable | |
| Posted by: joshc on 2022-02-23 13:20:26 So I went a did a silly thing which was buy a Portable. I've avoided them for years. Heard the horror stories about dead screens, dead hybrid modules, battery problems, yada yada yada... Anyway, I ignored all the sensible reasons to not own one and bought it anyway. Non-working and non-backlit, no charger. It arrived today, and well... the back of the unit was all wet/sticky... not a good sign. I open it up and yeah, the lead acid battery is all wet on the outer casing. Removed that, put it in a zip lock bag for now.  The 9V battery... yikes... leaking green goo everywhere. We're off to a great start here!  And sure enough, it made a nice mess in the chassis:  So I clipped the 9V battery off, too much gunk there and it also had a bad repair to it. I carried on with disassembly. Hmm... sticky residue on the hard drive too. Nice.  Even the speaker has sticky goo on it...  More gunk...  Tearing it down...  Finally... the logic board...  Actually not too bad... leaky caps but I don't see any trace damage, overall its pretty clean despite the leaking batteries in the machine.  On removal the caps revealed lots of fluid underneath them, not visible at first...    Giving it a good wash..  Bottom case has those cool signatures of the product team...   That's where I'm up to so far, next up is drying the board off after an IPA soak, and putting new capacitors on. | |
| Posted by: ScutBoy on 2022-02-23 13:48:56 Welcome to the journey! It took me two non-backlits to make one good one. When I found my backlit, I got lucky and all I needed was the recap and a new battery. Working on refurb of a backlit now for a friend of mine. | |
| Posted by: Byrd on 2022-02-23 14:01:35 You'd be the man for a @joshc restoration! Finicky machines, but surprisingly nice to work on once disassembled. It looks like the battery goo from the batteries differs to that of the usual corrosive mess we see, so think you'll be lucky. I'd use a third party 7.5A 1.5A charger to power it up; even a recapped Portable charger I'm finding is not trustworthy. | |
| Posted by: LaPorta on 2022-02-24 17:40:42 Best of luck here, I’m looking forward to the re-working. There are also some caps (regular radial electrolytic if I’m not mistaken) behind the LCD. It actually is pretty easy to work on: I recapped it as one of my first SMD cap recaps. Here is a good direct replacement battery: 
EnerSys Cyclon 6V 5AH AGM X Cell Battery - HAWK0809-0012Cyclon 6V 5AH SLA AGM Battery makes an excellent replacement option for telecommunications, UPS backups, emergency lighting and medical equipment. Maintenance-free and spill proof design.
www.batteriesplus.com
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Posted by: Trash80toHP_Mini on 2022-02-26 11:55:26I'd use a third party 7.5A 1.5A charger to power it up; even a recapped Portable charger I'm finding is not trustworthy.Sounds good to me, but make sure to get a usable battery from your local Home Improvement boutique to keep in circuit whenever you finally try powering it up. @techknight has drummed the that requirement into my skull. Don't power up without it, may cause irreparable harm IIRC. There's a thread about this somewhere. | |
| Posted by: joshc on 2022-02-27 09:38:15 Quick update. I've recapped the logicboard. My bench PSU arrived and I did some tests. I was getting some load, but it won't start. The SWIM was bad. I've now removed the SWIM. Now there's less load, but it still won't start. The Hybrid "seems" to be working, and the 5.2V regulator is behaving as well. I need to do more diagnosis/troubleshooting to see what's going on. | |
Posted by: mg.man on 2022-02-28 01:42:03but it still won't start. The Hybrid "seems" to be workingHave you tried "pressing both the Reset & Programmers (Interrupt) switches at the same time"? Also, do you have a good / fully-charged main battery installed (i.e. not just the 9V)? FYI, you can get a brand new 3 cell lead-acid battery that you can attach the old terminals to and - with a little bit of padding - will fit nicely in the battery bay... here's some pics of one I'm using...   The tabs from the original cells (once removed from the casing) have been soldered onto the new battery.  | |
| Posted by: joshc on 2022-02-28 02:08:40 @mg.man Yeah, pressing both interrupt and reset to keep the Hybrid in check. Half the time power is applied, there is no load, and then half the time there is load - I think that's the Hybrid playing its tricks. I'm not using a battery yet, I'm applying 6.5V set to 2A max current with my bench PSU on the J17 connector which is effectivly the same as using a battery. I've been told the 9V is not important for it to actually power up but a lack of 9V could explain why it requires me to power on the bench PSU and power it off and then on again before I get any load. I'm not using the original wiring harness/battery terminals at all yet as I don't trust it because of the battery leakage that was going on there. When I have more time later this week I'll start buzzing out all the important stuff, right now I don't even know if every trace from the power management chip is OK or not, if there's any problems there it will stop it from starting. A quick photo of my test bench setup...  | |
| Posted by: mg.man on 2022-02-28 13:11:28 I'll caveat this by saying I'm not a Portable guru... but from what I know, the 9V battery was mainly there to preserve RAM contents if the main battery was swapped out. The Portable has an "always on" (albeit "sleeping sometimes") design. The idea was it could be quickly awakened from "sleep" when you're on the go. There is a microswitch that switches power to the 9V when the battery "cover" is removed. When the cover is in place, a tab on the cover "closes" the microswitch - "enabling" the main battery. I'm not sure from your bench photo how you're handing this configuration... The power circuit on the Portable is certainly "unique"... 🤔 | |
Posted by: moldy on 2022-03-01 10:57:33A quick photo of my test bench setup...@joshc are you providing power to all 4 pins in the Molex power connector? @techknight indicated in several posts back in the day that connecting only to a single positive pin might fry some of the logic pins and indeed, if you look at the schematic (it's available), you can see that they're routed separately. I can confirm that the bench supply on all 4 pins is enough, 9V battery is not needed. Additionally:
Mac Portable M5126 doesn't boot after recapHello, I've managed to return a tiny bit to my 68k Mac hobby and decided to try to clean up an unmolested backlit Portable I had lying in the closet. What I've done: Didn't try to turn it on, just disassembled it. Desoldered all capacitors. Most of the cap juice seemed fresh and still mostly...
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