68kMLA Classic Interface
This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.
| Click here to select a new forum. | |
| Reverse engineering the LC II Logicboard | |
| Posted by: max1zzz on 2021-11-16 16:16:49 With the (hopefully) final revision of the LC 1 board and the second revision of the LC III both with JLCPCB for manufacture it;s time to turn my attention to the LCII. This was initially going to be the second board LC board I worked on before that pesky LCIII board distracted me... The boards I am working form where kindly donated to me by @cheesestraws for reverse engineering, Many thanks for that! I haven't taken pictures of most of the process because it's more or less the same process as the previous two boards but here's when I'm at currently:  About 2/3 of the top copper is done, should only be a day or two more till this side is finished 🙂 Then it's on to the bottom side which is always fun due to the huge amount of birdseed that's always on the bottom side..... I'll post more updates as I work on the design 🙂 | |
| Posted by: max1zzz on 2021-11-30 14:38:36 Top and bottom copper are done!  Next is the inner planes which are always fun.... might have to get the sander out for that 🙂 | |
| Posted by: mmu_man on 2021-11-30 14:43:32 Yay! | |
| Posted by: cheesestraws on 2021-11-30 14:54:26 You are alarmingly good at this. | |
| Posted by: LaPorta on 2021-11-30 15:25:45 I am amazed at this! | |
| Posted by: max1zzz on 2022-01-07 09:59:31 V1.0 has been completed and is now with JLCPCB for manufacture 🙂 Boards will hopefully be here within a week or two | |
| Posted by: cheesestraws on 2022-01-07 10:08:52 I'm waiting with bated breath! | |
Posted by: max1zzz on 2022-01-07 10:18:34I'm waiting with bated breath!So am I! | |
| Posted by: max1zzz on 2022-01-14 10:14:25 PCB's are in!  | |
| Posted by: max1zzz on 2022-02-08 14:31:23 I finally managed to get a board assembled enough to test:  I didn't really expect it to work, after all V1.0 boards rarely work out of the box however I flicked the switch and was extremely surprised to hear a clear chime! But I was getting a solid white screen.... The I realised I hadn't installed a VRAM simm, quickly installing one presented me with this:  It works! 🙂 I can't quite believe it boots with no modifications! (well, at least it boots this far, I still need to solder the rest of the connectors and fully test it so there is plenty of room left for things to not work) | |
| Posted by: mg.man on 2022-02-08 14:42:02 Amazing! Bravo! | |
| Posted by: max1zzz on 2022-02-12 15:57:34 The board has now been fully tested, everything on it works with no issues! Now that's how I like my V1.0 boards 🙂 | |
| Posted by: mdeverhart on 2022-02-12 16:29:02 Awesome, that is amazing. Good work! | |
| Posted by: Franklinstein on 2022-02-14 08:43:50 Nice work. I was briefly considering asking, "why not just stick an '030 on an LC board? Same thing," but then I remembered there are actually a few notable differences, primarily the 68882 socket (pads, at least) in the LC II and dual floppy support in the LC but not both in the same board. Easy things to overlook since most LCs had only one floppy drive and LC IIs didn't actually have the FPU socket but still important distinctions. At least now you should be able to install the FPU socket without having to clean out the board first. | |
| Posted by: mmu_man on 2022-02-14 10:34:32 Look ma, no bodge! Kudos! | |
| Posted by: mdeverhart on 2022-05-21 11:04:40 @max1zzz Any chance you can post this board (and the IIcx one) on your GitHub along with your LC and LC III? Thanks! | |
Posted by: max1zzz on 2022-05-21 11:49:01@max1zzz Any chance you can post this board (and the IIcx one) on your GitHub along with your LC and LC III? Thanks!Yes it will be soon 🙂 I just need to do the "paperwork" (BOM) for the LC II and the IIcx needs the rev 1.1 board tested (I have the boards, just need to find time to assemble one and test it!) If anyone needs a PCB in the mean time let me know | |
| Posted by: mdeverhart on 2022-05-21 11:54:57 Sounds great - I thought that was probably the case, just wanted to check (and had to remind myself that you’d done the LC II). Thanks! | |
| Posted by: max1zzz on 2022-06-07 14:26:09 Board layout, gerbers and scans are now on GitHub: GitHub - max234252/MacLCII_Reloaded: 1:1 Reproduction of the Macintosh LC II PCB1:1 Reproduction of the Macintosh LC II PCB. Contribute to max234252/MacLCII_Reloaded development by creating an account on GitHub.
github.com
As with my other designs these are provided under a non-commercial licence but if you are a repairer and want to offer transplant services (or have any other commercial use in mind) please contact me | |
| Posted by: demik on 2022-06-07 15:41:19 Don't have a LCII, but thanks for your work ! | |
| 1 |