Kurzweil mark 5

[Ken Davies]

Looking for schematics for the mark 5. Recent lightning strike has reduced output to badly distorted sound from keyboard and demos through the speakers and headphones. Any help would be greatly appreciated

[Jazz P Bass]

Have you tried a Factory Reset?

[Ken Davies]

I have tried both resets. The second method went through the test sequence a number of times and produced 3 tones each time and sequenced through all the selector button leds but unfortunately the result is the same. The keyboard produces very quiet notes with distortion. Turning up the volume just increases a lot of background rumble and selecting any reverb causes even more background noise. This is both through the speakers and when plugging in headphones. I wonder if it is the pre-amp that has failed if there is one however the test produced clear normal volume tones.
thankyou for your help so far

[g1]

If you can get good clear tones from the test mode, that suggests all the analog circuitry should be ok. The reverb issues further suggest the problem is in the dsp related circuits.

[Ken Davies]

If it is the DSP circuits does anyone have schematics for those?