Recent content by Mark_W

Btw this should be the correct position for t2 marker, to measure the end time of a complete cycle: Assume 50% duty cycle, the frequency should be 1/(t2-t1)=1/(800ns)=1.25MHz Or we can just use oscilloscope's default frequency measurement reading, it should take care of everything.

Grabbed my friend's se30 and removed rom, here's the result: Early revision with socketed cpu and pals. A2 is also 1.3mhz. And I think I know what's wring with the guide. Take a closer look at oscilloscope screenshot on pg 46, the frequency is calculated by 1/(t2-t1), but t2 is placed at...

I took another look at the repair guide: And on page 46 the scope shows square wave with 50% duty cycle, and its measurement is indeed 2.6MHz (pg 46): If ROM is installed, A2 will not show a perfect 50% duty cycle square wave, instead some irregular waveform as data is flowing on the bus (pg...

I opened my se30 again tonight as I noticed some of the smd 74hc logic ic legs are still a bit tarnished and reflowed all of them. While I'm at it I did more tests and found some interesting results. If I remove ROM stick and let it boot to horizontal bars, all frequencies on address lines are...

Hello @GreenBar0n, I have an se30 motherboard behaving just like your first one. Leaked capacitors didn't cause any damage but it was battery bombed. I had to repair about 10 traces near the battery socket and it was still stuck at simasima screen (horizontal bar as it has Ti vrams). All clock...