It power up so at very first time. But believe it or not I have found the cause for this. The center pins on both 2k trimmers on faulty side were unsoldered. I’m glad I discovered this before changing components. It took me three days to find those missing joints. Wonder how many more there could be?
Well, I'm sure you will find and solve the problem with your amp. It's mostly a matter of time and some things just need some more time.