Sounds like a book for young electronics engineers...
Though someone might have ran into this problem before so up here it goes:
I have just spent another 2 hours mucking round with a 8 x AMC7135 driver in an attempt to make it into a triple LED driver (parallel) and while in theory everything should be working fine.. its not.
Basically I have de-soldered all 7135s off the bottom and have cut the negative traces between two of the 7135s, splinting them into three groups. From here I soldered and de-soldered a few times in an attempt to get them piggybacked and get each group to deliver 700mA. Testing them on an XB-D along the way everything was fine until suddenly the LED no longer wanted to glow. It was not the LED and it would not go regardless of which group I soldered it to. I took some "tail-cap" readings and seemed to be getting 40mA.
I desoldered all the chips and soldered one random one on and it worked fine again (including modes so it isn't the ATtiny). Sweet thinks I, I've fixed it.
Soldering all the chips back in place, careful not to got solder on the cut tracers and the likes.... and it doesn't work.
Any ideas? My logic is telling me if they are in parallel one bad apple shouldn't spoil the bunch (so to speak), am I wrong? And if so are there any measurements I can take (with a DMM) to figure out which one it is?
Could be that the control line from the ATTiny is stuck on one of them, which is preventing the ATTiny from turning any of them on. Unfortunately, the best recommendation that I have for you is to pull them all off, and then start soldering them back on one by one until it stops working.
