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Adding 3.3v to 6200

Posted by: killvore on 2026-08-06 07:22:04 Hello! I have a couple of 6200s and I want to update them with some better logic boards and PSUs. I just love that form factor but the 6200 itself is pretty underwhelming, so I want to make these bad boys shine 😄 My question(s) is what will happen inside a 6200 if one of the inputs from the PSU is now 3.3v? I have not been able to figure it out from reading powercc.org or this comprehensive but ultimately confusing thread - they don't identify the 3.3v rail for later machines and I find the edge connector mysterious! Since I'm not great at electronics on a component level, I think this ATX conversion PCB can be a good solution. This can also apparently route 3.3v from the ATX PSU, which would be great since I think Alchemy boards (5400 and 6400) require them to run. I can verify that the ATX-Q630 chip routes the different voltages correctly from the PSU end, so if someone has a pinout for the receiving end on the 6200, that would be super useful. I think one of the pins on the 14-pin connector acts as ground on the 6200 PSU, but gets repurposed to 3.3v in eg. the 6360, but I can't find a pinout for that either 😅 I'm more than happy to do a proper writeup for the community once I get this figured out! As an aside, the BOM on the ATX_Q630 has some deprecated parts, I can figure some of them out but I'm not super comfortable puzzling out non-capacitor components - if somneone has replacement suggestions that would be very much appreciated as well

Posted by: MacJunky on 2026-08-06 15:18:41 Check out P7-P8 on the powercc.org pinout.

Posted by: killvore on 2026-08-07 12:06:06 All right! I've tested where the PSU connectors on the computer end map to the edge connector on the logic board edge connector. The third one from the left looks like it is not hooked in to anything for older boards, and also appears to be getting 3.3 from the takky mod (orange line connecting P7-P8). So it's probably the way to go! Will post result once I get the adapter hooked up.

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