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. | |
| Recapped Mac Classic ii Checkered Screen | |
| Posted by: DomDom on 2022-07-26 18:20:00 I have a mac classic ii rev A and after a recap of the logic board still gets the checkered screen. I also have a working mac classic that I put the board into and still got the same pattern and I've been looking at the schematics and haven't found anything yet. Is there something I'm missing, a chip that goes bad, or what else can I do? | |
| Posted by: joshc on 2022-07-26 21:18:48 Can you post some photos of your logic board please? There could be cap goo under the Egret chip (U10) or around that area, because there are 4 caps there which all cause problems. Usually removing/cleaning it resolves this, but there can be other reasons for the checkerboard pattern.  Not the issue here but have you re-capped the analog board too? If not, that will be necessary for a Classic as they all have leaky capacitors by this point. | |
| Posted by: DomDom on 2022-07-27 04:17:47 You are pictures of logic board and what the screen looks like. | |
| Posted by: joshc on 2022-07-27 05:11:03 The board looks too dirty, there is lots of residue/goo around all over the place. This capacitor leakage residue causes shorts. It needs to be scrubbed/washed with soapy water, then rinsed well with isopropyl alcohol 99%, and then left to dry thoroughly for several days. Are you sure this has been recapped? This capacitor doesn't look new, it has damage to the top:  | |
| Posted by: LaPorta on 2022-07-27 05:18:45 In addition to the above, put your working Classic LB into the II, and see if it starts. Rule out any analog issues (though I doubt it with what others have pointed out. | |
| Posted by: DomDom on 2022-07-27 05:30:53 I have and the classic logic board works perfectly. | |
| Posted by: bibilit on 2022-07-27 10:09:52 I agree with all that has been said. Capacitors have been replaced in my opinion, probably new, but yes cleaning the board is more important than having new caps. Fluid is conductive and can easily make nasty things. the Egret is contaminated, should be removed, cleaned and soldered back. and yes, the AB board should have new caps as a minimum. | |
| Posted by: DomDom on 2022-07-27 10:43:53 Okay thanks everyone for the information and I will start doing this and in a couple of days I will reply back with the results. | |
Posted by: xeiter on 2023-04-29 07:22:25Okay thanks everyone for the information and I will start doing this and in a couple of days I will reply back with the results. How did you go? Did you manage to fix the issue | |
| Posted by: DomDom on 2023-04-29 08:10:59 It's been a while but I never did end up fixing it because the logic board booted but never actually worked properly only booting from floppy disks hard drive being iffy crashing during copying processes completely unreliable | |
Posted by: xeiter on 2023-05-05 04:44:08It's been a while but I never did end up fixing it because the logic board booted but never actually worked properly only booting from floppy disks hard drive being iffy crashing during copying processes completely unreliable Oh bummer, sad to hear. Sometimes we just have to give up - I am sure you still had a few handy learnings out of this case. | |
| 1 |