Prinyer communication error then Nothing Kaput

[Mkd3b]

Ok s2000 been working just fine played down to zero credits opened cash box to retrieve bills to feed for new credits machine comes back with printer error tried reboot still error pulled mpu to reseat still error try again jiggle some connection and then finally no boot No display all lights on board plus red flashing led
Have had Machines for Fifteen yrs or so and have never encountered this problem
Checked battery was down to 2.8 so maybe  it will be that. Any other ideas    Cleo 9 line 5 reel 

[Stayouttadabunker]

red flashing led is not good that's for sure.

Change the battery, re-seat the chips carefully.

[Mkd3b]

Will do that today
Put mpu in another machine  last nite and same result
Also swapped mpu to cleo from triple stars to see if would start up. Got to Alarm stage so stopped there.
Seemed to be so very stange that was playing moments before and only after removing miney from cash box and closing door everything just went to hell.
Looked on board for anthing obvious but nothing notable will change battrry shortly