Sterling 7 wont accept coins - newbie

[RodneyE]

Hi Everyone,
I am new to this site and I need help with a slot machine I purchased. I googled my issue and it took me to the old website and I read up on what helped others fix my same issue. Nothing has worked.
First the slot machine is a Sterlings 7. We purchased this machine with the knowledge that it would not accept coins. The just fall through into the coin return. The previous owner said the machine did work but it stopped one day and he didn’t have the knowledge to fix it.
My first question would be if there was an error code where would I see that? I noticed that the last game, coins played, win meter and credit meter do not light up. I played around with the coin comparator and tried to manually give the machine a credit and it didn’t work (the coin comparator does have a coin in it $.25). The MPU is 94014-Main4 if that helps.
I have ordered a refurbished coin comparator but it has not arrived and was hoping someone had other suggestions to try.
Here is a picture of the machine. If you need more picture please let me know.
 
Thanks in advance.

[RodneyE]

After replacing the battery on the MPU the machine lives again. The only issue I have is every time I turn the machine off and on I have to do a ram clear. Any suggestions.