Omnichord OM27

Is anyone here familiar with the inner-workings of the Suzuki Omnichord OM-27? I have one, haven't had it very long- the chord buttons fizzle out when I press them. This just started last night. It's not the speaker as the strum plate works and sounds fine... Haven't looked at any manuals...

I've decided to sample my Suzuki Omnichord OM27, key by key, via Studio One. Despite using a tuner plugin, I'm struggling to map the keys to their appropriate pitch. When I go up and down the scale, there still seems to be a slight mismatch (with some samples sounding higher, despite the tuner telling...