Need help and advice on fixing my Wurlitzer 200A

[Drew9783]

Hi EP forum, I need some advice on a Wurlitzer 200A that I have. The serial number is 107081L which I believe puts it at between 1968-72.

Some background:
I bought this from a church for pretty cheap about a year ago, knowing it hadn't been used in a while. When I got it, the electronics worked as they should, and I recorded a few songs with it. Last November I took it to a friend who works on pianos to do some regulation to it, and I just got it back. He did a great job with the keys and the action but I'm still having issues with the electronics. I am adept at soldering and working on electronics (I build guitars and amps) so I'm trying to figure this out for myself.

When I turn the piano on, the vibrato works and the volume work but the sound is very fuzzy, almost like it's going through a fuzz pedal. The sound is the same with the internal speakers, headphones and audio out. Most of the components on the board are original except for a few caps, so I went ahead and ordered a new preamp and deluxe board rebuild kit from Vintage Vibe that should be here this week.

Here's where I need help:
This is my first time working on an EP of any kind. I am unsure exactly the grounding points are. I've attached pictures of how I have it grounded now, and I need someone to verify that it's correct. I also need the full grounding explained to me for the piano.

So far I've tested points on the circuit and the caps seem to be relatively ok, the reed bar is getting +150v and the preamp is getting +15v. Is there anything else i need to be aware of before replacing the preamp and rebuilding the board? Is there something I'm missing?