Help With NES PPU Problem

[pedro]

Hi there guys i have this NES with PPU problems for quite some time, and recently i wanted to buy a new one so i opened here on the foruns a WTB topic, now the user Calpis asked me about the problem and as i didnt know much about it, just that was a PPU problem i showed him these pictures.





Now after showing these images he said that most likely there was an adress line from the ppu A8 pin to the sram pin 23 i tested for continuity and it was positve.

I also noticed that there were some corroted traces under the sram, but a quick test of continuity told me that there were no problems on those, so i ask, is there a fix here or i need a new NES?

UPDATE: STATUS REPORT

1º Corroted Traces not a problem.

2º PPU Pin 30 to Vram Pin 23 - OK

3º PPU Pin 25 to Inverter Pin 3A/5 - OK

4º Inverter Pin 3Y/6 to Cart slot - OK

5º PPU Pin 24 to Vram Pin 20 - OK

Thank you for your time.

[pedro]

Status Report added with new info.