RESOLVED!!!
See last post for details if interested. Thanks for the feedback all!

-----
I am hoping someone has encountered a similar problem in the past and lead me down the right path to resolve this error. I have a old Kitamura MyCenter 1 with a Fanuc 0M-B control. Everything has been working fine for the couple months I've had it. I have non-absolute encoders which require you to home each axis when the machine is started.

My shop is very hot right now, around 95F while the AC is out. The previous owner mentioned the machine would not stay running in his shop (very hot also) without a fan on the open cabinet. I never had a problem though until last night. I was running parts and got a 920 Watchdog Alarm Error mid run of a program I have been running a lot. I was scared because it says to replace the PCB, but searching mentioned some just had to put a fan on the open cabinet like the previous owner mentioned (I don't know if this is the error the previous owner would get though).

I powered down, put a fan on the cabinet, powered up and all way fine it appeared. I went to restart my program but when I went to rehome my axis's Z homed fine, but X and Y did not.

X and Y both appeared to be homing right, where it decelerated as it was getting to the end, but instead of stopping at machine zero it continued to -2.002mm and through an overtravel alarm.

I retried homing a couple dozen times with the same result, even after cycling power and letting it sit for a couple hours between tries.

I don't know what to look for or what to do from here to troubleshoot it because it cannot locate home. I'm worried that perhaps something fried relating to the limit or encoder hardware/logic now and that is where that 920 error originated from and not the heat of the cabinet. I would have thought it was a bad switch if it didn't happen right after the 920 error and if it weren't both X and Y at the exact same time. I'm thinking perhaps the key to this is that it is X and Y and not Z and that will be an indicator of what is amiss to someone who knows the way the hardware works.

Can anyone advise on what procedures to do to investigate this more? I have manuals but it makes no reference of anything related to homing, switches, overtravel or anything I am describing.

------

Above is the original symptom/issue that caused me to start troubleshooting myself. The issue mentioned in this section cannot be resolved until the above root problem is fixed. But to test the limit switch I put the rapids to 1% and tried to home Y. While it was moving I depressed the top switch, released it... kept moving. I did it a second time and it stopped and Home light for Y lit up. This gave me hope but it caused the machine to think the end of travel (home) was way short of where it should be.

So I tried booting with CANCEL P held down to override the softlimits, which worked. But when I would tried homing Y in that mode it would just continue on until it hit the lower cam/switch (the E-stop switch). On mine I have two cam/switches on each axis. The upper cam/switch is the homing and the lower cam/switch is the emergency overtravel. When the upper switch first hits the cam it causes a deceleration, and then when it clears the cam it knows it is home. At least that is how I think it works, maybe it doesn't.

At any rate, I've made things a bit worse since I can't get reset machine 0 on the Y back to where it should be, but at least I was able to see that the machine can still home (green light and machine 0 reset) just not where it should happen.