Pin 4 looks fine, the issue is pin 5. That should be around 5v.
Pin 5 is tied directly to the (-) power supply input pad, the orange wire on page 5 of the Choral Reef doc.
See what voltage you have at the negative pad. It should be the same voltage as pin 5, if it is and if you can, disconnect that wire and check voltage at the wire itelf.
If you're getting the incorrect 8.47v at the wire when connected and 5v with the wire disconnected, you probably have a solder bridge somewhere.
If the disconnected wire is around 8.47v, the 5v supply itelf is the issue.
Hope that makes sense.
Just be real careful if/when disoldering from pcbs, I have damaged a few pads doing this.
In this case, you'd just be pulling the wire out so heat it up, pull it out and if there is a bunch of solder left in the pad itself, or if your solder sucker doesnt get the solder out, heat the pad again and use a toothpick to clear out the solder. But again, if you heat it to much or push the toothpick in to tight, you can damage the pad.
If you can check the disconnected 5v supply line without pulling the wire, better yet.
1978 Gibson Les Paul Standard, Cherry Sunburst