Hi Don,
I believe that's why Q1,Q3,Q18 as well as various caps and other components were replaced, I just inherited this keyboard as non working(missing -5V rail?), but many things seems wrong. Questionable solder joints, ground leads to various components IC4-IC3 and some caps, really shitty work I must say done by previous owners, half desoldered CPU, new eprom...etc..I'm taking my time to review everything and clean it up, hoping to revive it soon. I managed to order the original transistors from ebay, so its just a waiting game now.
Any other suggestions appreciated and thank you very much for your help. Have a great day