Fabieville,
I'm digging up this old thread of yours because I was experimenting with repairing PV panels on the weekend.
A friend of mine has a number of bad panels, but believed that something was wrong inside the junction box. We cut a bunch of them open together (the boxes are potted with silicone inside, making it hard to break in).
Once inside, we found that each of the under-performing panels had either disconnected wire tabs or blown diodes.
The diodes are installed between parallel strings of cells, to allow one string to keep producing even when an adjacent string is shaded, so these are called "bypass" diodes. Not the same function as "blocking" diodes.
We replaced the diodes, re-soldered the tabs, and restored 4 panels to 100% power!
I'm writing up a diary entry, and I'll post it up soon, but I was also researching if other Fieldlines members have done the same and your question came up.
Hope it helps - only 8 years later!