[mamed]

just recieved two o2s both have solid red led and auto power on when plugged in. set jumper no effect. Swapped psu no effect, swapped ram with known working no effect. swapped motherboard and it worked a treat now we are getting somwhere. swapped cpus between boards, working board worked with the nonworking boards cpu but not vice versa, same working ram used in both so clearly mobo is the issue. Ive read that this is caused by a system board pull when powered. So before I begin checking chips I was wondering if anyone has ever diagnosed a common chip on a system board pull when powered.

Also on a cool side note I think my massive anxiety and panic of the past 2-2.5 years has cleared up to where I can work on things again weeeeeee lol.

[weblacky]

Truth time...This is an UNDER-RESEARCHED area, because up until the pandemic, O2 mainboards were so cheap that repair was never even a thought! With recent price increases on everything this will have to be rethought.

It wouldn't be that hard if you have duplicate mainboards with save part revision (but one was toasted by a an errant pull), just using diode mode on a multimeter and start measuring every single thing you can find until you find a shorted component...or conversely if you have curve tracer (like me) you do the same thing until the impedance and the deflection reading wildly change...then you've found the damage (or some of it).

I'd assume it's NOT the CPU, and likely is either a chipset or a "start-up" mechanism that does the power-on, CPU setup, and then resets the for execution...maybe the power-on-reset system? But it's all undocumented.


But I'd be confident it's physical damage and not corruption of an EPROM or something of that nature...so trackable by measurements. If you do find that there's a commonality it would be a great secret to know for main board repair. However gaining that knowledge is going to be much more than the cost of an 02 Mainboard. You could definitely think of it as an investment if you're willing to see it through and have the measurement equipment to actually find the part and that also assumes the part is still available. The O2 uses quite a number of chips that are no longer produced or supported.