Vintage Synth Repair

Hi,

I have a Lowery Parade which I purchased sometime in the 80's.  It has
been sitting in my living room untouched for quite a few years. 
Lately, I decided to start playing again.  When I started playing it
sounded awful.  All the keys are stuttering which I presumed meant
that a cleaning was in order.  My husband and I took off the back,
took one look, and closed it back up again.  Yes, it is very dusty!  I
thought it would be a simple matter of vacuuming it out and maybe
cleaning the contacts but we don't even know how to get to the inside
of the keyboard and all those wires.  I don't want to do any damage. 
Is this something we can do ourselves or do I have to find an organ
repairman?  It really was working fine the last time I used it. 

By the way, we are both familiar with taking our computers apart,
upgrading cards and harddrives etc. so we aren't completely ignorant
about electronics.  I realize that this organ is completely downlevel
but I don't think I will be buying a new one so it's this one or nothing.

Thanks for your help!!

Cass