Just an observation but you seem to be jumping about all over the place in your attempts to fix your machine.
If you receive the machine as a non-worker in unknown condition then you have to be thorough, logical and systematic in your approach.
Use the Pinwiki as has been suggested.
Start off by ensuring power supply board is putting out correct voltages.
I personally replace 40 pin male and female interconnectors, new ROMs and sockets and also re-pin switch row and column connectors on CPU/driver boards.
Then get a test chip and go from there.
Everyone is willing to help but rarely will anyone be able to diagnose the issue in one sentence
Forget the blanking circuit components to begin with. The blanking issue is probably from other problems with the boards rather than blanking circuit component problems. Been there done that
Again, start with power supply.