Bally S6000 Bad MPU - Monte Carlo

[Colorado]

I have a Bally S6000 Monte Carlo with a bad MPU.
During power up the reels just pump, no error codes in windows.
It won't accept a ram clear, error code screens blank...
I put a different MPU in and it powers up.

Can someone tell me which chips are required to switch from the original MPU to the different MPU.
I switched U28/U43 - - U20/U18 - - U30/U45 - - DS1/DS2/DS3 and removed U24

Am I missing anything ??
Colorado

[LINDAM]

Re: the bad MPU, check the pins where the MPU plugs into the backplane.

Re: new MPU, You will need to do a ram clear 1st. make sure all the dip switches match the old MPU.

Start with that.

[Colorado]

Thanks.   
I did the ram clear first thing yesterday directly after swapping all the chips mentioned in original message.  The dip switches were knock out type.  I also swapped them out yesterday. After making the chip swaps, I was getting an 1800 error with the new MPU.  I didn't have any new batteries on hand so until I am able to get a new battery  thought I'd ask if there were any other mandatory chips that would need carried to the new MPU. 
Good news is I was able to see the 1800 error.  Wasn't able to see any errors using previous MPU.
I'll post an update once I get past the 1800 error. 
Colorado

[Colorado]

Got past the 1800 error by swapping chips into an MPU that had a good battery.  Did a complete ram clear everything works well except if you let the Slot sit without touching anything for a couple of minutes it goes into some kind of sleep or hibernation mode,  freezing up. If I hit reset button on MPU it comes back up and works fine as long as it's being played. 
Has anyone ever came across this condition before. 
Colorado