I have been having trouble it turns out with poor power regulation and voltage clipping from the utility company frying my Weber WZ-68 rectifiers.
It seems that here in Costa Rica the power supply is poorly regulated for several reasons and we have a lot of voltage spikes and brown outs occuring which have caused my Weber WZ-68 to burn out several times.
At $22 bucks a pop I needed to find a solution quick. This no doubt applies everywhere else from time to time.
I am sending this in as a possible preventitive solution for those people who were on the mysteriously burnt out rectifier thread recently.
Both the resistors and the diodes in my Weeber WZ-68 have burnt out at various times. I tried re-building them changing just the resistors, then with just the diodes as well with both always using the stock parts. no luck!
I was still having issues with the rectifier getting fried during these times when the voltage was too high. I have measured as much as 138.6 volts for a few seconds!
The last time I fried one in desperation I contacted Bob and with few suggestions from him I was able to discover the likely cause and solution.
I then tried rebuilding a Weber with(IN5408)diodes and the stock resistors ((18 0hm-10 watt). The diodes are bigger but I got them to fit neatly on the little board in the weber.
I had to install the resistors a hair higher to clear the diodes.
i also took the time to swaet the solder out of the pins and put the wires in as the same way as they camefrom weber. All the wires I spliced on were part of a failed rectifier. It may have been a contributing factor i am not sure but it would seem to be worth the effort to do it this.
I also put a piece of heat shrink on all the leads of the resistors to make sure they don't short out with the diodes and the top of the cap which is very close to the leads on the resistors. So far they are bulletproof.
We had a terrible storm two days ago when I was listening to my ST-120 and I put my meter on there and measured two spikes of 127 volts and one of 129.3 volts both only for a few seconds in less than half an hour. The weber was fine.
My point of all this is that the more robust diodes seem to do the trick fit well and work fine.
if anyone else has a similar problem with webers it could be the power fluxes and tougher diodes might be the answer for them as well. Although the stock diodes are 100 volts they are only 1 watt and the bigger ones carry 3 watts a safety margin may be what's missing.
Hope this is of some help to someone.