Mackie Swa 1501 correct hcpl A3100 operation

This was taken after a very long and painful repair, multiple blown semiconductors, zeners and resistors, even after replacement of the common failure components i had a strange gate drive at Q12 and Q15, turned out to the the through hole connection underneath the main hv filter caps C12 and C17. Repaired by removing the caps and soldering cut off legs from 1/4 watt resistors through the holes to both sides of the board then re fitting the caps. This video shows the correct operation of the hcpl A3100 as this part of the hv switching confused me at first until i watched another video of a repair on a swa 1801 by john which pointed me in the right direction as he was very helpful! Nobody shows exactly how this A3100 operates so thought this may be useful. The white led is soldered across pin 6 Output and 7 Gnd and shows the drive for the Q4 irf640, if this led strobes or pulses as mine did at first, be sure to remove and test transistors Q1 2n3906 and Q3 2n3904 as these directly deive the led inside the A3100, if one or both are shorted you will get an odd signal going to the A3100 and end up with a pulsed output instead of the output remaining on once the voltage threshold has been reached for the low voltage rails.