The WPC games will reset if the voltage goes below +4,7 VDC. But when you measure in attract mode without any heavy load (No coils that fires.), Pinrepair says at least +4,92 VDC at TP2, but even if you have a higher voltage than that it's no guarantee that you won't get a reset.

The first thing we do when we have a WPC reset is to press in the cables in the following IDC-connectors: J101, J102, J112, J114, J116, J117, J118, J210 and the cables at the Z-connector (DM, IJ, STTNG & TZ).
(WPC-95: J101, J127, J128, J129, J138, J139, J140, J141, J210.)
Se photo below of the tool we use. We bought it at Pinball Center in Germany.

If pressing in the cables doesn't help, then we change BR2 and C5, and after that the problem is normally gone.

Williams probably had their reason to change from bridge rectifiers on the WPC-89 games to diodes on the WPC-95 games, and in my opinion there are much less reset problems with the WPC-95 games.
The bridge rectifier can test good, even if the component is over stressed and the capacitors will dry out over time, so I would recommend you to change those components, if pressing cables in the connectors doesn't help.

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