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Home Forums PM8500 no signs of life — #18 PM8500 no signs of life — #18
Post #18 by trag
Source ForumPM8500 no signs of life — #18
CategoryHardware
Post DateTue, 26 Feb 2013 - 22:50
Original URLhttps://68kmla.org/bb/threads/pm8500-no-signs-of-life.27418/
Post
The x500 class machines will power-on even if there is no CPU card installed, but they will not "bong". To get the "bong" or any other sound, you need a CPU card to run the Power On Self Test.

The reason they will power on even without a CPU card is that the little 7805 microcontroller in the CUDA chip handles the ADB bus and the Power-on logic. If it is getting 5V trickle, it's happy to turn the power supply on when someone presses the power switch either on the logic board or on the keyboard.

I think CHC's advice is spot on. Try another video card.

I think I have some VRAM around here. I'm trying to remember whether it only works in Catalyst-based machines (7200 and clones) or doesn't work in Catalyst-based machines. I know it has a flaw that causes one or the other, but I don't remember which. For that matter, I'm not all that sure where it is....

mp.ls