If it has the original caps and bridge rectifiers I would replace them. I also re-flow all the pin headers or replace ones that need it if I pull the board to do the bridge & caps.

Cheap & easy.

Yes, it could be something else or a combo of other issues but for me its standard fare to "bullet proof" a board doing a minimal shotgun approach on perishable components. In this case HS2 is likely 12 years old but still a candidate for bridge and cap replacement and the standard fare of checking connectors for issues and re-flowing header pins. Correct line voltage is assumed......

The only problems it could possible create is if someone is doing the replacement that does not know what they are doing in which case they should not be doing it if not comfortable doing so.

It could be something as simple as coil diodes or something more sinister, stay tuned.

Someone was reading Clay's guides & had a pistol soldering iron.....
You can tell a professional iron becasue it has headlights on it.

Bridges and caps are cheap unless someone uses pliers or a torch to remove them.

That could be some Kester 44 prototype stuff........

Kester 44, extra crispy.