Has anyone ever repaired one of these modules from a Weil-Mclain boiler? WM97+ P/N 511-330-270 which has multiple circuit boards inside. It runs on 24V. I have a problem on the Display Board part number 511-330-428 where several components burned out. One electrolytic capacitor marked C5 with markings (224 5.5V AN) SMD. and another capacitor C23 that had exploded so bad it disintegrated and pitted the board. It burned the board so bad it ruined the traces which I have to repair but have no Idea what that capacitor was. Contacting Weil-Mclain was useless as it is a proprietary engineered item that they will not give any information on. The capacitor that exploded gets power from an Z2 SMD Zener diode SOD 123 with the markings WJ Y5. I looked this up and think I found that it is a 15V 5mA zener but am not sure.
Trying to find that display board is impossible even Weil-Mclain does not list it and said none are for sale and there are no schematics, parts lists or diagrams for that board. Which is why he said just buy the whole unit for $600. I don’t see why I should have to do that when I can just replace a few components for a couple bucks. I will never buy Weil-Mclain anything ever again.
As far as C5 and Z2 I have those in stock but if I can not identify what that exploded capacitor was how can I fix it? Is there some calculation I can do that will give me the capacity of that capacitor? and I am not even sure what type it was SOT, SOD, electrolytic, Tantalum, ceramic or film ? All I know is it was an SMD as there are no through hole components on the board.
Thanks for any help.
I forgot to post picture but here they are. Notice how badly C23 burned out. I can not tell what that was and can find no information on line.
[img] 
[/img]
[img] 
[/img]
D6 cleaned up nicely and tested good but will probably replace it as well if I can find out what C23 is most likely 50V but unknown capacitance and get a replacement. Also fixing the traces is going to be a chore but I can manage as long as I can get all the replacements. Also the Zener Z2 also might be bad and I will take it out and test it as it may have been the part that failed and caused C23 to cook. or it was C5 which was bulging and tested bad. I tested ALL of the resistors and jumpers and they are all good.