S2k intermittent bill validator com error

[Phan000]

Have an enhanced board.  Works well.  Mei cash flow bill validator, takes all bills and cycles normally.

While machine is idle, bill validator will reset, and cause communication error.  Clears with door open and close.

What would cause this?  Bad power supply?

[qbert]

Try removing and reseating the small com board that the MEI head plugs into. ( It should slide straight out)
Remember to take the cash box out before reinstalling the com board.

[Phan000]

After trying that solution, I decided to replace the whole bill validator with a WBA.  Just to be sure it wasn’t the issue.

Still getting intermittent bill Val comm  error.  Causes a reset of netplex, and a restart of system with occasional no display.  Sometimes will go 4 or 5 hours with no issues.

Could this be a failing psu?  It’s a known good board, so not really sure what to try next.  Thanks.

[rickhunter]

Doesn't hurt to try a new power supply, I would also look at harnessing making sure there's no visible damage to validator harness to the backplane.

[Phan000]

I am still not having luck with this machine.

Swapped boards, inspected bv harness.

Machine will work for 14 hours,  then throw a bv comm code.

No idea what to try next.

[Stayouttadabunker]

I am still not having luck with this machine.

Swapped boards, inspected bv harness.

Machine will work for 14 hours,  then throw a bv comm code.

No idea what to try next.

Which boards? MPU? Backplane?

[Phan000]

Swapped enhanced mpu.  Changed VFD driver, installed new WBA validator, cage and harness.

[Stayouttadabunker]

I'll give you an idea to try....haha

Rick mentioned the checking the harness to the backplane - which you've done but...it goes to the only board you haven't swapped?

Maybe try sticking that question validator into a different cabinet to see if the billval comm error pops up?

It's somewhat easier than swapping backplanes?

I know, I know...you've already swapped BV's and still get a bv comm error...oh well....gotta switch out either the BV harness completely or the backplane....your call.

There's a small chip on the backplane that holds information - What info that chip retains exactly, I don't know.

I wonder if this chip has ANYTHING to do with why your BV only works for so many hours, than resets like the machine has lost it's mind?

Anyway, I hope you get it running right.

[rickhunter]

Could also be something else in your netplex bus.  Try disconnecting the printer to see if the problem goes away.  Anything in netplex goes wonky, the whole thing goes wonky.

[Phan000]

I’ll try the printer.  I have to key the machine and disable right?

The only spare backplane I have is not enhanced.

Looking at some old threads,  the backplane was the cause of a similar gremlin.