Start button strange behavior

[GroM]

I have a strange behavior of Start button. I think that this is the Start button, because when you enter text enter screen it immediately goes back.
I've tried different button bar and even power board. I've checked with multimeter that start button isn't grounded to mass (0). Normally ohmmeter shows something about 700 and drops to 0 when pressed.
I didn't checked main board - power board ribbon, but I don't think that it should be a problem with it.
Do you have any other ideas? Why this is happening?

I also tried ofw 5.00 and cfw 5.00-m33-4, but this doesn't matter.
In the key test in psxchecker the start is all the time red circled - and pressing Start button has no action.

[Crumbz]

try replacing the home bar (if thats what is on a psp 1000 cuz im not too familiar with the 1000 version) it just sounds like the start button is either stuck or your ( ) button is somehow pressing down on the /\ [] ( ) X Pad.

Hope this helped.

PS if you added and hardware mods check to see that none of your wires are pushing on anything.