Badwolf I think this seems to be a Catch-22 thing here.. When the caps are on the oscillator it seems to upset the CPU more because of the duty skew.. BUT.. the FPU clock is "out" by about 5% ish.. Then when the caps are there.. its pulled closer to 50:50 duty.. then the FPU works.. I won...

So it’s possible that fangs trace was actually caused by the CPU failing and not the CPU failing because of the fangs trace? The clock switching signal looks perfectly fine.. And then when it crashes it goes to the fangs signal.. But that is what I was saying, that I don't get how that could happen...

More investigation with the 50MHz not being stable. Spraying the freezer spray on the CPU makes it stable. I'm not using the FPU at all currently (it is not plugged in). There is no loading on the oscillator currently either. I know these CPUs will work on the H5.. But the Falcon 5V is actually slig...

Got it working again..I am using the same 40MHz OSC as before.. But ironically started working when I removed your clock hold off

Oh after about 10 minutes it did the first dash on TOS's boot up RAM test

Badwolf wrote: ↑Thu Nov 17, 2022 3:46 pm Between the 33 and the PLD.

Looks the same both sides of the resistor.

Something else has gone wonky somewhere either there has been a bad connection develop or something else is broken because it seemed to be running at 50x less speed just.. The clock is still switching away.. Bizarre..

Badwolf wrote: ↑Thu Nov 17, 2022 3:35 pm What does the input look like as this is happening?

What input are you referring to ? The oscillator ? that is fine..

The plot thickens once again

Wait, that's the CPUCLK output line? Yep. You need to get the CLKOSC input line on the second channel, then. It looks like it's trying to produce a 66% duty wave. BW But it only does that when it crashes.. It looks fine when it is switching between 16Mhz / 50MHz otherwise. I'm currently trying to f...

That's not a trace, that's the oscilloscope monster's fangs! It seems the does that when it crashes. I do see some relative good clock switching when it is running but difficult to capture. But even so I don't know why that would happen at 50MHz anyway. Should be pretty much a passthrough from the ...