68kMLA Classic Interface

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LC630 DOS Compatible no video on DOS side
Posted by: CTB on 2022-04-22 23:42:09 I have been trying to get the DOS side of my LC630 going. I have the PC Set control panel set and it sees the DOS card. When I restart the card I get the startup beep. However when I switch to the DOS side there is no video. I have tried fixed resolution monitors and multi scan monitors but I can't see anything on the DOS side. Any ideas?
Posted by: AndiS on 2022-04-23 04:06:57 No immediate idea, but which Mac System version are you running? I don't remember specifics, but I was never able to get this working under OS 8 or 8.1 7.5.x works fine though.
Posted by: jeremywork on 2022-04-23 04:38:20 It may be worth checking inside the case to be sure the video loopback connection is seated firmly in the GIMO port. Only some of the LC630 style boards have even have the connector (Performa 640; LC580 come to mind.)
Posted by: CTB on 2022-04-23 14:40:23 System 7.5.3 Update 2 and the loopback cable is installed.
Posted by: CTB on 2022-04-24 17:50:11 After getting the tip regarding the GIMO port loopback decided to dig a little deeper and have found the issue.😢 After cleaning it still oddest work. I think the socket itself is stuffed. I will transfer the whole DOS setup over to another LC630 I have and see if I can get the loopback board working. I might need to check the traces as after cleaning it still doesn't look good.
Posted by: jeremywork on 2022-04-24 18:43:24 Yikes! I was about to offer to tone mine out to compare, but I noticed this one's similarly afflicted. Was definitely cleaned up pre-sale, but everything else on the card seems to have escaped unharmed. If I can be reasonably sure everything's connected I'll post a pinout. No compatible machines to test with at the moment.
Posted by: CTB on 2022-04-25 15:07:06 Yikes! I was about to offer to tone mine out to compare, but I noticed this one's similarly afflicted. Was definitely cleaned up pre-sale, but everything else on the card seems to have escaped unharmed. If I can be reasonably sure everything's connected I'll post a pinout. No compatible machines to test with at the moment. View attachment 40956 The rest of my logicboard is fine as well. Just this connector. Something weird us going on to cause such isolated corrosion.
Posted by: jeremywork on 2022-04-25 15:38:43 The rest of my logicboard is fine as well. Just this connector. Something weird us going on to cause such isolated corrosion. The GIMO port is directly adjacent the 4.5v clock battery. If your board still has a battery should definitely remove it, given all that blue corrosion.
Posted by: CTB on 2022-04-25 15:42:54 Battery removed long ago and board thoroughly cleaned.
Posted by: AeSix on 2023-07-21 12:20:59 I did a thing. I toned out the connections. I'm not a pro at making diagrams, so I used physical images as base/background. I also numbered the edge connectors backwards from pin 1 on the ribbon cable. shrug "Label" side "Solder" side - note, the two tones of orange are both GND, vias and contacts darker, plane lighter orange
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