One other thing I did notice was that a surface-mount capacitor had literally fallen-off the piezo-pickup preamp circuit board from where it was supposed to be soldered, at first I thought it was just a small glob of solder, then I did a double-take and realized what it was, I think I have a conventional capacitor I can use as a replacement, I'm wondering if that's the reason why the piezo's were a bit horrible-sounding because that smd cap had fallen-off the circuit board....hmmmm....I'll have to wait and see, the piezos did sound a bit harsh and metallic to my ears, maybe this is why.....hmmmmm.....
The loose smd capacitor:
Where the loose capacitor was soldered to the piezo preamp board (where it says C13):
Update:
I had a look at a magnified view of the pic of the piezo pickup preamp board, and it looks like some of those other smd capacitors have dried-out/leaked a bit, so, looks like this whole fixit-job just got a bit more complicated, I think I'm going to have to replace every single one of those smd capacitors with conventional ones, fortunately I have a good supply of conventional ones on hand......down the "rabbit-hole" we go.
Don't you just love it when what should be a simple job, turns into something more complex?