Lighting Now it's my turn COB DIY

Well your half way there then! I was a field service tech For H.P. and I've seen it all.....lol! always start at the plug. You want to know what a sad customer looks like? Tell him on the phone to check the power plug "I did, come fix it!" so, this is what was know as a 4 hour call, meaning we had 4 hours to complete a fix. Customer payed ( about ) $400/hr. for a 4 hour call!

Power plug was about 1/16" not pushed into the back of the printer enough................

And from there just test every connection with a volt/ohm meter. When you test resistance across an LED you get 1 on your meter (infinite ) meaning max resistance if your testing the wrong way across the led. Correctly connected yo should get a small amount of resistance. write this amount down. Check each chip. They should be very close in resistance readings. If one is much higher, the connection is likely bad or the chip has issues. Rarely the chip. Poor contact between the power pad on the chip, and the electrical contact of the cob holder. Sometimes its the wire not stripped enough, etc and some of the insulation is preventing good contact. Stranded wire with too many strands broken off leaving too little wire, faulty wire connectors. " If it can fail, it will..." Meaning test each and every part.

Most likely cause most of the time is a poor connection causing resistance in the circuit. Increased resistance = lower voltage across the cob
Thanks pop. Your much better at this sort of thing. I test stuff by plugging it in with my fingers crossed.
 
I hope this helps. Setting up a chip etc, time consuming. I'm going to make a thread on testing connections. It make take me a day or 2, this is going to be a crappy, crazy week for me......
 
That would be a huge help to everyone Pop. Besides over or under powering a cob I haven't had any issues at all thankfully. One of those wall watt checkers might be the simplest ways for noobs. This light could be fine just not to his expectations. He read off 187 v in the line of cobs so they are receiving the power. I'm not sure if that was in the end cob or if that even matters either.
 
A watt meter is handy, but may be misleading also. Enough resistance from poor connection will actually increase the power draw. Everyone who is going to work with electrical components needs a volt/ohm meter and needs to learn how to use one. Probably the most important tool you can have for this.Most electrical problems can be solved with a meter.

I would check voltage at each cob. Testing the string MAY tell you something, no test is to be ruled out till an answer is found.

That would be a huge help to everyone Pop. Besides over or under powering a cob I haven't had any issues at all thankfully. One of those wall watt checkers might be the simplest ways for noobs. This light could be fine just not to his expectations. He read off 187 v in the line of cobs so they are receiving the power. I'm not sure if that was in the end cob or if that even matters either.
 
I learned to use a meter in Auto shop of all places. Lay upside down in the front seat of a 1957 Chevy tracing wiring in the dashboard for 2 days.......
 
@pop22 @BigSm0
One question to you guys... 1 will buy 100x16cm heatsink and want to cut them to 50cm. So I will have 2 bars for more even light spread. How can I wire 2 cooling fans and 4 COBs to driver (one for fans, one for COBs)? It's too complicated design and rather go with 100cm lenght?
 
how are you mounting the driver(s)? Simplest is if using a single driver for the cobs and one for the fans, is to simply extend the wire to reach the next light. The connection for the COBs is still in series. Fans are wired in parallel, just again run wire from one fan to the next, leave some extra so that you can adjust the height of each light. Use zipties or whatever and ties loose wires to the frame of your tent to keep it neat.

Series Wiring:

series wiring.jpg




Parallel Wiring

parallel wiring.jpg









@pop22 @BigSm0
One question to you guys... 1 will buy 100x16cm heatsink and want to cut them to 50cm. So I will have 2 bars for more even light spread. How can I wire 2 cooling fans and 4 COBs to driver (one for fans, one for COBs)? It's too complicated design and rather go with 100cm lenght?
 
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