@catzymbs something does not look right with the solder bridge on C601, which could go to R602 but the orientation at the point of your jumper looks off as well as the location of the bridge. Let me see if we can clear the schematic up a bit. I hate that they have both sides on one page. I attached some images just for reference of what those parts are and how they are connected. There is nothing missing between R601 and R701 but it could use a bit of cleaning up. Lets see what we find around that area. I also flipped the image of the underside so that it would match your image. that was done for clarification only.
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You mentioned “corrosion around IC4” that area looks good. Was that a typo?
@catzymbs something does not look right with the solder bridge on C601, which could go to R602 but the orientation at the point of your jumper looks off as well as the location of the bridge. Let me see if we can clear the schematic up a bit. I hate that they have both sides on one page. I attached some images just for reference of what those parts are and how they are connected. There is nothing missing between R601 and R701 but it could use a bit of cleaning up. Lets see what we find around that area. I also flipped the image of the underside so that it would match your image. that was done for clarification only.
[image|2547128]
[image|2547129]