I've moved twice since obtaining the schematics and 'am still looking for them. In conversation (2004) with the owner of Rondo ( co-designer). He mentioned that they only produced a couple of the models and found that they weren't very popular. The one that Rich ( our lead player ) had got hot as hell. It had the power transistors mounted on a heat-sink affixed to the back of the cabinet and you didn't dare touch it once the thing warmed up. Another interesting note were the speakers. It had what JBL called "free floating" coils and you could see them pumping  when a heavy chord was struck. The other notable was of course the neon lighting bolt on the grill. According to Rondo it was a functional part of the amp and not just for looks. At the time, Rondo's main stay was found in Fender and VOX. I had a choice  (price range limited) between a new Super Reverb or a used Viscount and stuck with Fender. I think I paid $450 for the amp and later a new tele with case for $215.  I'll keep looking and let you know.

I was in a band in the '60 and the lead guitarist bought a Power Sonic Amp ( with lightning bolt)
from Rondo Music in Linden, NJ. Years later I became interested in the amp and phoned Rondo. I spoke with the owner and found out that he and an engineer buddy designed and built the Power Sonic. It came with 2-12" JBL speakers (Free floating heads). He and his buddy only build a few of these amps. It was just about the time that transistors starting to appear in guitar amps and most folks were a little leery of using them. As I recall the amp had a large heat sink mounted on the back and got rather hot. The owner sent me a copy of the schematics. All hand drawn. Cool.