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. | |
| Macintosh 128k: Logic board, which revision? | |
| Posted by: Paolo1960 on 2022-03-12 12:19:53 Hi This is mybsecon post, and my first thread, in this fanatstic forum. I read several discussions to repair my 800ks (or try to repair my mac Plus- still on going) By the way, I have recently bought on ebay a 128k for more or less 400usd (I live in Europe). Once arrived I opened it to see what was the cpu used and other little things. Unfortunatelly it was not the one that most people define "the 128k logic board" (+ a lot of rust) So now the question: has the following board been upgraded? Is there anything in this board that can be considered "original 128k?     Thanks a lot for the feedback, Paolo Ps: it powers on but the sound is totally absent. If you have any idea on what could be the issue It would be great | |
| Posted by: bibilit on 2022-03-12 14:24:46 As far as i can see, this is the first revision of boards. Following units had a label for either 128 or 512k ram. Yours is 128, and ram is original, don’t see any work done to it. | |
Posted by: Paolo1960 on 2022-03-12 15:41:31As far as i can see, this is the first revision of boards. I said upgraded, or reworked because the James'one shoulb be the first release: Link In the one I have Ram slots do not have the apple logo on the left side, but on the right. Cpu is missing the "Apple 83 etc etc" thing, and is also called HD6800. Maybe there were some revisions before the dual logic board (128k/512k) Thanks, Paolo | |
| Posted by: cheesestraws on 2022-03-12 16:08:09 Different manufacturer for the ICs, is all. Note that several on your board are manufactured by Oki, including the DRAMs. Consistency implies they're probably original. I'd guess manufactured in a different region? The board is a first-iteration 128k board. | |
| Posted by: bibilit on 2022-03-13 00:07:35 Rust is probably related with battery juste above the LB, nothing a good scrub cannot get remove. | |
Posted by: Paolo1960 on 2022-03-13 04:18:55Rust is probably related with battery juste above the LB, nothing a good scrub cannot get remove.I will use isopropyl alcohol (99) to clean all the board. As far as I know It should be safe. Different manufacturer for the ICs, is all. Note that several on your board are manufactured by Oki, including the DRAMs. Consistency implies they're probably original.The manufactur theory is intersting. I will try to analyse other 128k boards Thanks | |
| Posted by: Paolo1960 on 2022-03-13 11:32:25 So, I disassembled my other Macs and this is what I found: 128k - Dual Logic Board  512k - Dual Logic Board  All of them are different, but The position of the components is always the same. Concerning the sound issue, is there any suggestion on what to check? Sorry for the consecutive posts, Paolo | |
| Posted by: bibilit on 2022-03-13 11:58:56 Bad speaker ? | |
| 1 |