Recreating the Mac's CUDA / EGRET microcontroller chips - can it be done?

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DosFox

DosFox

New Tinkerer
Dec 3, 2022
17
10
3
The 341S0788 is compatible with the Colour Classic, which I believe the Mac TV is based on. It's the CUDA that's in my colour classic after all!

The low standby voltage may be down to U28, so it's worth seeing about replacing it.

However I would first double check with an oscilloscope to see if the CUDA clock is running.
 
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d3jsp

New Tinkerer
Mar 9, 2026
2
0
1
Yeah, the clock should be fine since it used to turn on and boot with non-responsive adb inputs.
What is strange is that mine has 5v standby voltage with the original cuda, but only ~2.5V with a known working 341S0788.
Swapping back to the original cuda and it still won't power on. Made sure I checked my soldering is good
 
kefkafloyd

kefkafloyd

New Tinkerer
May 22, 2023
21
20
3
Massachusetts
www.userlandia.com
d3jsp said:
Hey all, does anyone know the proper replacement for a version 2.38D cuda for the Macintosh TV?
Mine didn't have ADB and I couldn't find any broken traces. I swapped it for a 341S0788 from an LC475 but that didn't work and did not turn on. Standby power was only ~2.5V.
Swapping back to the original Cuda and it still wont turn on. What could I have fried on the board, would it be U28?
Click to expand...
Check to make sure the CUDA reset switch isn't shorted to reset due to cap leakage. That kept my Mac TV from booting until the switch was removed from the board.
 
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