The 68E09 on voice board may be defective. I had one Xpander on repair and it had very similar issues. After testing all parts between two CPUs I swapped the CPU from Rhodes Chroma CPU board which I had lying around. The new CPU did the job. The same Xpander (which had multiple problems, failed disp...

Hi,

I had same problem and the reason was failed uPC271C / LM311 comparator (IC8) on PGM-board.