Vintage Synth Repair

Hi,

I have a MKS20 that was not used for about 1 year. 2 days ago a turned
back on and now the sound is very distorted, from the main and phone
output.

If I maintain a steady notes I can hear some loop of something (of
about 2 secs) (but maybe is common in the RD1000 architecture and now
picking I'm missing it)

I can here also an echo kind of slapped one (very faint). I have non
chorus or vibrato active and there is no delay on the mixer.

I tried to clean the RL1 (the only relay on the effect board) as
suggested on the board (thanks Bob) but there is no good result.

Do you have any idea ? Any troubleshot procedure?

where I can find the pdf for the Service manual ?

thank you
Antonio