strange error code for 5500 slot

[badbaud]

We got two 5500 machines I have never seen before. The first is called "Ring the bell" and the other is "roll the dice".

These machines have high toppers and a second 5500 board inside the top.

The batteries on all 4 boards were dead so we replaced the batteries and put our chips in each board to make sure the boards worked.

We can't get the boards work with the original game chips and we get a 91-FF error code on one of the machines.

I assume this is some kid of comm error from the bottom board to the top one but am not sure.

Anyone know what this error code is on a high topper?

[AnotherTech]

You are right, it's a comm error between the boards.  You need to set the options correctly for them to communicate.  Unfortunately, I don't remember how to do that.    

FYI, these games were a hassle to keep running even when they were new.    They caused me many headaches. 

[badbaud]

I'm hoping that the error will disappear after I return the boards to the machines.

Didn't even know there was a second board up top until the error code came up and we started poking around.

The options should already be set unless there are some magical button sequences we need to press to enable the game after both batteries are replaced.