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Message: <blockquote data-quote="Tony" data-source="post: 161550" data-attributes="member: 1">I finally got around to working on Matt's lights that he brought me to play with. He had a power surge at his house and both lights died. Thankfully, one of them was just the PSU which is just a 19 volt laptop power supply essentially. The other light had a still good power supply, but the light was dead. He told me about it and with me getting more and more into component level repair, I told him to bring them down. This was the same time he stole his T-Maxx back.... lmaoWell, I needed to order some things from China to do some testing so I had to wait quite a while before I could do any 'real' testing or even see some of the things on this board. Well that stuff arrived and it turns out, I needed NONE of it. Well, almost. I had narrowed the issue down to a direct short to ground. I tried everything I knew to find this friggin short and I could not find it. I removed components and the short would go away, but the component would test good. Finally after a few hours of playing with this thing I said screw it. I had nothing more to lose, the light was toast regardless so it was time to force some voltage into it. One of the items I ordered to do this stuff was a regulated power supply (very cheap and not what I need, but it is all I have that I can regulate). It only goes to 15 volts and maxes out at 1 amp. So I connected my probes to the output and put the probes where the power wires went (I had removed them)At first I started out at a half volt and watched the board for some magic smoke. Nothing.... I looked at the amps and even at a half volt it was pulling 1/4 of an amp. So I knew if I could get enough power pumped into it, the little sucker would either pop or smoke, so I kept going. I finally got up to 2 volts before my PSU started kicking off so I backed it off slightly until it would stay on and kept an amp going into it. But still, no smoke... So I took a cotton swab with alcohol on it (rubbing, not drinking) and started going around the board. The issue... It is covered in silicone. The light goes over a saltwater aquarium so it has to be coated. This causes the alcohol to just bead up and not show what is getting hot. FINE!!!!! I took my FINGER and started touching the board in different places to see if I could find something warm. Yup, that did it. I had been feeding voltage to this thing the entire time and when my finger hit the component, I knew it. Holy hell was that thing hot!!!! But guess what... I found my short to ground. So what was it? It was an N-Channel Mosfet...[ATTACH]21293[/ATTACH] That little mosfet completely disabled a $400 light! As soon as I removed it, the light started working, but without the ability to control the color. It is stuck right in the middle so the same amount of white light as there is blue light. But I can adjust intensity  and I think this is about where Matt had the color set. I guess I could hook it up to my apex and find out if I can adjust it through the controller... I did order 3 of those little mosfets just in case I screw one up which is likely. Oh, and what was the cost of that little 3.4mm X 3.4mm X 1mm chip that killed a $400 light? $1.05..........</blockquote>

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