That's right, I checked at Zeus too and on the internet and couln't find any information for A841.
I have bought the bundle kit from Zeus for repairing Antminers but seems I can't use for Avalon. It is weird that no information is provided for these type of miners. Also here it's difficult to find someone who has information for these boards.Will contact Canaan to see if they could provide any information.
Meanwhile will try to figure out the how the signal works comparing the good and the broken one.
Thanks guys anyway

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ZeusBTC doesn't have a guide for this unit and I can't find any hashboard diagram for Avalon 841.
Why not try to compare the two hashboard that you know working and the broken one?
I don't know what exactly this unit hashboard looks like but I think you can follow the tracks on that hashboard and compare the resistance between the good and bad hashboard.