Frispel
sedan 2001
Replacing BR2 and/or BR1 on WPC-S and Prior:Splitting the Large Heatsink.When replacing either (or both) bridges BR1 and BR2 on WPC-S and prior, both bridges will have to be dealt with. These two bridges share a single large silver heat sink. Since they both share the same heat sink (and one failed due to heat), the other probably will need replacement shortly. If either BR1 or BR2 is bad, replace them both. To remove them, both will need to be unsoldered from the Driver board, and the heat sink un-screwed from the bottom of each bridge. The new bridges are then screwed to the heat sink, and both bridges re-installed (it is much easier to install the bridges if they are both already screwed to the heat sink). Also I am personally cutting the heat sink in half when I do BR2/BR1 bridge replacement. This just makes replacing one bridge a lot easier. If BR2 is bad but BR1 is fine, I don't want to unsolder BR1 in the process. The driver board's plated through holes for these bridges take enough abuse, so doing any unnecessary desoldering is a bad thing in my opinion. Hence the heat sink is cut in half. This is optional of course, but it is something I do now. The other reason for splitting the heat sink has to do with expansion and contraction caused by heating and cooling of the BR1/BR2 heat sink. If BR2 gets hot, it will expand the shared heat sink, forcing its partner BR1 to move a little. Likewise if BR1 gets hot, it can force movement of BR2. This puts additional pressure on the bridge's plated through holes, which can cause solder joint cracking. And this in turn can cause game resets. For this reason, it's a very good idea to cut the large single BR1/BR2 heat sink into two parts. This way movement of one bridge's heat sink will not affect the other.
Insurance: Installing Bridge/Capacitor Jumpers.Another problem with the bridge rectifiers/diodes and the filter capacitors are their solder pads and plated-through circuit board holes. The WPC driver board is a double sided board (that is, it has "traces" running on both sides of the board, both leading to different components). Soldering of both top and bottom traces is done on the bottom (solder side) of the board. The plated-through circuit board holes allow continuity from the solder side traces to the component side traces. Since the components themselves are in the way on the top side of the board, it is hard to even see the component side solder pads.
To fix this problem, it is recommended to add jumper wires on the solder side of the driver board. This is done to back up the bridge/capacitors' component side board traces. The most important bridge/capacitor to jumper is BR2 and C5. Jumper two 18 guage wires on the solder side of the driver board from BR2 to C5 (positive lead of BR2 to positive lead of C5, and negative lead of BR2 to negatvie lead of C5). This will help prevent random game resets. All the other bridges/capacitors can be jumpered too. Installing the Jumpers.When installing the jumpers, first label the back of the driver board. Use a "sharpie" pen and label the bridge, and its "+" and "-" leads, on the back side of the driver board. The positive lead of the bridge is the one offset lead in the square. The negative lead is diagonal the postive lead. The other two diagonal legs are the AC leads. Also label the capacitor and it's positive lead with a sharpie pen (the positive lead on most of the filter caps is the "top" lead). Double check all potential connections with a DMM, and buzz out the jumper paths BEFORE you install them (installing a jumper incorrectly can cause SERIOUS problems!). This will make installing the jumpers much easier and error-free.