[462ron]

Ron this a shot in the dark but maybe the reason for the voltage differences between the good channel and the weak one might be attributed to the differences between the original transistors and the universal replacement ones as far as their operating characteristics are concerned. Out of curiosity I would check caps C14 and C26. If they were open I would think that would reduce the signal across the primary of T2 thus reducing the drive to the output transistors creating less output to the speaker.

Ron