SONY 29” AE1C Chassis – TDA8170 – Field Collapse Issue

[bowls132]

Is there a technician out there familiar with the history of the Sony AE1 chassis series that can advise a retired ex college if there is a known issue with Sony & the TDA8170, is/was there an official fix if so what is it.
After replacing short circuit IC502 TDA8170 and open R530 1R2 in my own set field collapse was still present, even after replacing every capacitor and diode in and around the field output stage and checking and rechecking every resistor the dreaded white line still remained.
I have been able to resolve the problem by adding a 10M9 resistor and 0.1uf in parallel from pin 7 of the TDA8170 to 0V rail, this restores both normal height adjustment and field linearity

[tv.service]

Maybe the s/c in TDA8170 affected LOT if supply comes from LOT?

/janne