E-Mu Emax I Keyboard Keys Intermittant

Hi, I have an E-Mu Emax I keyboard 1000. The keys don’t work intermittantly on random keys, the key may work and then it will not. This is all the way up the keyboard. Also when in stereo, the sound may or may not cut out on either the left or right side randomly. Using an external keyboard has the same issues. If I tap the key and listen through one of the 8 channel outputs, they key may sound once and then be silent the next seven taps. Channels 5, 7 and 8 sometimes don’t make any sound.

I also notice that if I go into the Master settings and disable the top 5 or 6 channels the problem goes away for the key operation, although the sound is different than when the keys work.

I have put a new power supply in, I figured the old one is quite old. No change.

I reseated all the IC chips. No change (but did fix some other problems with the sequencer function and software rev complaints).

I ESR checked all the electrolytic caps, replaced one (was slightly out of spec). No change.

Is this perhaps the Scanner CPU causing this? I do have an Emax II rack and could see if the problem follows a scanner chip swap, I think the Scanner chips are the same, although I haven’t opened the Emax II yet.

Any advice welcomed. I have also posted on another forum with little response.
Mark A