SHURLOK ECU repair ?

[Shagwaggon]

Hi all
03 citi golf carb (new spec dash)

So my hazards have been playing around for some time now , draining my battery over night and after buying a new switch and checking ground connections I decided the ECU had to be the culprit.

So I removed it , inspected the mother board and noticed a small patch of oxidisation due to moisture by the looks of it. So I cleaned the board as best I could and put it back in the car.

Now the hazards don't play up as much but still turn themselves on now and then so it's not a permanent solution.

Does anyone know of someone who knows how to repair these boards or run diagnostics on them without breaking the bank? Or know about ultrasonics which may be able to clean off any other impurities on he board.

Not keen to buy a new ECU and still pay to have it coded as well.

Thanks in advance for any advice