On that particular board -- ALL high current connections are to the bottom of the board, there are no high current connections solely on the top of the board so through holes are never a problem. Majority of connections on top layer are test points, MOV connections, a couple low current connections, one redundant high current connection (GI) plus lots of redundant ground connections.

Don't worry about the HV voltage -- that one has a typical range but in real life, he varies quite widely depending on his load.

The switched lamp voltage, on the other hand, is an issue.
When you power this up - what is connected to J1 and J3?
Particularly J3, pin 6. J1 pins 3, 7 and 9.

With fuse F1 pulled -- can you measure the AC voltage between E9 and E10?

OK -- quick look suggests that the switched lamp output may be shorted.
First thing I would do is narrow things down a bit. Unplug connectors from J1 and J3 to see if this TP1 brings voltages back up.
With fuse F1 pulled -- did you measure directly from E9 to E10 (see circled in pix) with meter in AC setting?

Your wires that connect to E7 and E8 -- you are measuring directly across the GI output winding. That will look like nearly a dead short with an ohm meter.

E9-E10 (resized).jpg

... edited post.
Don't 'stutter' on mouse button when pushing the "Submit post" button.

Hey, just noticed something in photo. Stern Big Game -- his J1 was originally an 8-pin connection. This board provides 9-pins to work with old and new games. For older games such as yours -- the 9th pin should be empty.
Looking at photo -- do you have wires in J1, pins 6, 7 and 8 accidentally shifted by one pin to pins 7, 8 and 9? This would do mean and nasty things to your TP1 votlage and probably buggerer Tp4 as well.

Wire_Error (resized).jpg

Might want to check other wires as well.
J2 -- pin 7 (AC power return) should be white. But if this wasn't connected to AC return already, nothing would work. A stern documentation error in wire color? Might check him to be safe.
On J2 -- I see an orange wire in pin 9. Manual does not show such a wire... but could be another documentation screw up in the Stern Manual. Maybe somebody else with a Stern Big Game can check this one.
Pin 3 connections look good based on this pix.