A few years ago, I picked up a "working" OR80 off Reverb. With my luck, it was junk. Had a horrible parasitic oscillation, and when I opened it up, I discovered it was a 72 OR80 converted halfway into a 74+ circuit. I say halfway because it was really poorly done and hacked together. Permanent damage was done to the PCB, so I decided to gut it and start fresh with turret board construction which I've finally begun.
My question today is regarding the rectifier section. The amp came with a separate connection on the PT labeled "SC-"(It appears it could be SCR, the last letter was hit with an iron) which I assume stands for Silicon Controlled Rectifier and was wired to the DC "negative" side of the rectifier bridge, which on the schematic goes to the ground. This is questionable to me. The center tap of the 190/0/190 secondary is correctly wired to the middle of the two larger filter caps.
Ultimately, my question is what is this "SCR/N" connection? A dedicated ground for the rectifier? Or a ground for the transformer? Should I just ground the rectifier connection the way it is on the schematic? The SCR terminal is the closest to the faceplate of the chassis. I haven't seen any photos online where the labeling was visible. It's definitely the original Parmeko transformer.
I will post pictures of the rig when it's done.
EDIT: I'm beginning to think it's a transformer ground. Let me know if anyone sees this and agrees!
EDIT 2: Final build pics below!
Cheers!
![Image](https://i.imgur.com/pM9FR7h.jpg)