EDIT: OOPs! Wrong series of chassis - huge difference in what my train of thought was. Your set uses the MCZ3001DB....I've always found it best to swap the D board, or go for the chip swap, but socket them and get spares.....
Genuine MX0841's ain't cheap no more:
https://www.encompassparts.com/item/...or_Mx0841-ab-f
Nor are the MCZ3001DB chips:
https://www.encompassparts.com/item/...1/Ic_Mcz3001db
I depleted my supply of them long ago - I still have two 2SC4834s for the smaller screen stuff.....
Those two chips are why I've junked more Sonys in the last 4 years. You can't go cheap with anything but the genuine Sony parts - the Chinese have mastered the fakes, and they don't hold up.
The ESI disc has a service bulletin for finding true MX0841's using capacitance of all things - the C-E junction has to have a certain picofarad value. Of 7 I had, only 3 checked out OK - the rest were obvious fakes already, but it validated the capacitance check as a way to rule out the fakes. I never got a fake from Tritronics (now Encompass, aka a Wall-Street-Run parts place....)