Sticking Home/Limit Switches - Please help

So I have been a long time lurker, and this is my first post.
I usually find all the fixes/info i need, but for this I am stumped.

The issues is as follows.

If only one input switch is activated (closed) then all others (open ones) work fine (on then off)
if two are activated (closed) then the rest all get stuck closed once activated and to not turn back off(go to open.

When this first happened I was editing some stuff in my HAL and INI, so I tried to revert the changes as much as possible - No Fix.
I then ordered a replacement BOB thinking this was the issue - No Fix
so I changed the wiring on my machine so all switches are NO (except e-stop) - Worked for a few homing cycles then broke again
I believe if I wire the E-Stop in NO then I should be able to home (as only one switch would be activated at any time)

This leads me to believe that something has Borked on my Motherboard

Can anyone please give me some pointers on what to test to diagnose and fix this gremlin... It's putting a halt on all my plans for my time off, beyond frustrating!

Thanks Everyone

BOB is Generic Green Chineese Board with Relay as sold by many retailers (says it has opto-isolators and limit switches have resistors on them)

Each Axis and the E Stop has its own input (4 in use)

Ok, I thought I would provide some more information as re-reading what I wrote is not completely clear.

Each Axis on individual Pin

E Stop = NC
Rest = NO (they were NC but same issue happens, just one step earlier)

When Homing:
Z will go looking for home, find it, and stay there (Switch becomes Closed)
X Will look for home, Finds Switch, Switch Triggers, X Backs off, Switch is still and remains triggered(This is the problem). X Keeps moving (its expecting the switch to become open but it never does)

As soon as 2 inputs are Closed, any others that are momentarily closed get stuck in the closed position. This is not a physical switch issue.

Problem confirmed using HAL Scope.

What kind of switches are you using?

Standard mechanical switches when I was running NC
Some 3D Printer Mechanical Switches (have built in resistors and handy LED) for NO (had them laying around)

andypugh wrote:

Is ut possible that the LEDs flow enough current to hold the pin high?

I dont think its the LEDs, I have tried plain mechanical switches directly and get the same result.

andypugh wrote:

capacitative carry-over in the multiplexer

No idea what this is
Any ideas to test?

Do you have a link to any info on the bob (such as where you got it from)?

I think the blame has to lie somewhere with the bob or how you've wired it. But we're only guessing since we don't know exactly what you've got or how it's hooked up.

Does the bob require an outside voltage source?

Todd wrote:

Does the bob require an outside voltage source?

This is a link to the exact board - but from a different supplier.
www.omc-stepperonline.com/5-axis-cnc-bre...iver-stv2-p-197.html

Yes It should have a minimum 5V but I also have 12v for the relay