Ugh I just got this error for the first time in years. It seems everything is fine though how should I prevent this from actually being a problem and be a headache? would it be the belt? I have some I change it if I am capable that is.
now switching sides I get the F5 error.

If you never replaced the loading belt, it's probably long overdue @ this point. Also, based on your description and the error codes mentioned, it all sounds like the loading belt as the main issue.

Here are steps I took to replace the belt in my Mitsubishi, M-V7057 (704, 79, 99 clone).


Pop the tray out and unplug the player



Remove the clamper assembly



Remove the old belt, clean the pulley parts w/ alcohol, and then replace the belt (part VEB-1184 or maybe SCQ 4.0 belt size)



Hope this helps.

U1 on my 925 was the load belt.

I have the same code on my CLD-D925 but it is intermittent, but I'm too lazy to completely fix it. I believe the F5 code will be gone when you replace the belt.

I changed the belt and almost thought the player had died since power was gone for a bit. until I plug it back where it normally is. so far seems to be good. but the belt that was in there hadn't lost its shape though I don't know. I have another belt if needed but it is nerve wrecking for the power to go out like that not off and able to turn back on but stop completely.