After troubleshooting found missing voltage on collector H702 transistor ( 4-5 volt) in driver section.
Problem solved by replacing R708 resistor 18k.
This time we did ” lazy” replacement . New 2 resistors 10k + 8k installed right on top of bad resistor. For saving time.
Technical review.
Nice small amplifier. Good performance. Nothing special.Power supply section extremely simplified. Classical 
old style engineering design.
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