Hi All,
I'm thinking I may have misdiagnosed a Fuel mainboard issue, possibly due to the fact that I couldn't find the PROM serial output...and I don't have my L2 up yet right now to bypass that stupid output config setting...and the front panel becomes solid red (which indicates mainboard failure or failure to load PROM) during boot (but fans runs, etc...).
I'll explain my theory but question first: When the Fuel experiences a CPU mismatch error (e.g. putting a 600Mhz PIMM in a Fuel mainboard configured for 800Mhz PIMM)...does the front panel LED code result in a SOLID RED?
If not, what LED code is presented when the booting process is halted for this exact condition?
Further regarding thread:
https://forums.irixnet.org/thread-4012-p...l#pid29549
I have recently taken the PROM firmware chip off a mainboard that I believed had a corrupt PROM. I just recently got around to dumping that chip's data using an EPROM programmer and compared it with the hex dump given to me by Jwhiat for an 800 MHz Full system, running 6.210 firmware. The dump came back identical in every respect. Which means there's no corruption in this PROM. Now that doesn't mean there's not some electrical problem or mechanism that's at fault but now I'm wondering if the stated PROM problem was in fact a normal system halt given that I didn't have the correct CPU installed and that the default values from putting in a new snaphat and brand new L1 RTC did not redirect any type of PROM Console output and resulted in a solid red front LED panel error code.
I took the lack of output after NVRAM reset to mean that the PROM never started. But I've come to see that the PROM serial output problem seems to be occurring again (strangely) in others Fuels I'm working on even after I replace their battery backed components but not having undergone the special "reset all" procedure that we now use that involves the POD and GO CAC maneuvers.
So to my own surprise I just realized that just because I couldn't find the output and it indicated not loading a PROM or a mainboard failure (BOTH could be happening) that the problem may in fact of loading due to misconfigured PIMM. So before I get my L2 finally working that could redirect this problem output, that I just can't find, I thought I'd ask those that have already done this CPU upgrade or have tried to perform a CPU mismatch on a Fuel exactly what the front panel code displays when this occurs.
Because a part of me thinks that this was trying to tell me that I put the wrong CPU in because in reality the PROM firmware dump showed me that this was an 800MHz system and I put a 700Mhz PIMM in to see what would happen because I assumed I'd have access to the PROM serial output that would allow me to see the errors associated with doing this as we've seen posted online time and time again. I saw no PROM output so I assumed no PROM was running. But maybe if the LED code is the same in this instance, then maybe if I finish my L2 project and use that that potentially I'll discover that it was simply a CPU mismatch and that was the only thing holding me back.
So that's the overall thinking here and I realize that nobody actually documented this aspect. We all assume that you can see the serial output but nobody said what happens when you can't see the serial output.
So the question is what's the LED error code during a CPU mismatch? If I'm right and it's a solid red LED then that's probably what I was staring at and I need to approach this in a different way. However because I don't have an 800 MHz CPU I will be attempting a CPU downgrade firmware flash on a separate chip and soldering the end of this board once I get such an image. I'm currently working on another board that was supposed to provide this image but it still has some electrical problems. So I'm working on one board to try to get the firmware flashed in the perfect position to use on the second.
I'll produce individual posts about each of these research threads.
Hopefully I'm right in my assumption but I need to know if I'm not. People with the knowledge on this topic please comment, it would help me out greatly in this undocumented instance.
Cheers!
NEED -> 
