The S5 Hashboard is a simple design, but tricky to troubleshoot & repair because of it's string design often gives a "One Down All Down" result. I will at some point do a Trouble Shooting & Repair thread, but although my understanding of the Board is improving all the time I do not feel qualified to do that yet. I also only have one failed board to play with which is slowing things.

Back to your question it is really too complicated to cover in a few lines, however the first step is to check the voltage across each of the 15 nodes (The capacitor you have just replaced) These should all be about 0.8V, a "faulty" node will be more or less than this, however this is complicated in practice because a fault driven increase or decrease on a node will also result in the converse change spread over the remaining nodes.

Next thing to check is the 14V from the Upconverter at the Top Right of the board, and then check that the 25MHz oscillator Y1 is running.

Bypassing nodes is possible, but only practical if it is one of the upper nodes that has failed, and even then you would need to reduce the 12V supply accordingly.

Bottom line is almost certainly an ASIC or two has failed (The Node voltages will help confirm this) and the only real course of action is to remove & replace. The replacement would have to be taken from another board as that is the only source...


Rich