Repairing COB LED PAR's

[Uriahdemon]

Hi, I have a number of QTX PL-COB6 LED PAR's. A few of them are now starting to exhibit the same issue and that is the Green chip is failing. Is there any way I can cost effectively fix this i.e. get a replacement part (and what part would that be) and fit them to the unit. The fixtures themselves are reasonably cheap but very bright and I would like to extend the life of them if possible.

 

Any help or pointers much appreciated please.

[Gerry]

How about contacting AVSL, the suppliers/manufactures?

Contact them at https://www.avsl.com/about/contact

Cheers

Gerry

[Uriahdemon]

Hi Gerry,

 

thanks for that but I am looking to do a self repair not only for cost reasons but also to learn a bit about this type of thing if possible.

How about contacting AVSL, the suppliers/manufactures?

Contact them at https://www.avsl.com/about/contact

Cheers

Gerry

[gyro_gearloose]

You'll first need to find the make and model of the original COB LED. Given that your fixture is at the budget end of the spectrum, the manufacturer most likely used an off-the-shelf LED. However the LED market changes quickly, so you may find that the LED you need is no longer available. Your best bet is to cannibalise one of your fixtures and harvest its working LEDs.

 

Something I did notice in the fixtures manual is that it somehow manages to produce 180 Watts of output while consuming only 20 Watts of mains power. One or both of those numbers might be wrong! :D

[Uriahdemon]

Thanks for the info. Yip very much so a budget fixture but good performance (when it works). I have no knowledge of how to check the output and/or wattage but I do know these are bright and that is what I like about them.

 

I would be more than happy to cannibalise one or two for the greater good but don't know what parts I need to replace. Although these are 6 bulbs the normal routine when they fail is for 3 to all go at the same time and the other 3 will follow in days/weeks. So although whatever part sits behind those 3 bulbs that is causing the green chip to fail may be replaced from another unit they will go eventually. So I was hoping to get a repair job done and replace whatever it is that needs replacing with some better ones so the lights will last longer.

You'll first need to find the make and model of the original COB LED. Given that your fixture is at the budget end of the spectrum, the manufacturer most likely used an off-the-shelf LED. However the LED market changes quickly, so you may find that the LED you need is no longer available. Your best bet is to cannibalise one of your fixtures and harvest its working LEDs.

 

Something I did notice in the fixtures manual is that it somehow manages to produce 180 Watts of output while consuming only 20 Watts of mains power. One or both of those numbers might be wrong! :D

[Ynot]

I had to do a similar operation on our stock of (also budget) Stagg KingPARs.

a) the main reason, I think, for the failures was they tended to overheat. And that overheating was down to a poor ventilation system which just sucked in all the dust & crap that gets generated during the life of a stage with several full builds a year.

b) the replacement COB chips are no longer available. I had the very last 11 chips that my Stagg dealer could find ANYWHERE, as they've moved on to something different now and don't manufacture back-catalogue spares. Something to definitely bear in mind when buying cheaper.

c) replacing those chips wasn't difficult per se but was fiddly - it involved getting into the front of the lantern and soldering at a steep angle due to the case being in the way. Didn't appear to be an easy way to get the whole kaboodle out of the case so just ran with it.

 

 

 

[kgallen]

I have had LED PARs fail on a colour channel due to the LED string driver chip failing rather than the chips themselves. Are all green LEDs out or just some of them (former could be the driver chip, latter the chip itself).

 

Kevin

[Uriahdemon]

Thanks, some good info there . !!

I had to do a similar operation on our stock of (also budget) Stagg KingPARs.

a) the main reason, I think, for the failures was they tended to overheat. And that overheating was down to a poor ventilation system which just sucked in all the dust & crap that gets generated during the life of a stage with several full builds a year.

b) the replacement COB chips are no longer available. I had the very last 11 chips that my Stagg dealer could find ANYWHERE, as they've moved on to something different now and don't manufacture back-catalogue spares. Something to definitely bear in mind when buying cheaper.

c) replacing those chips wasn't difficult per se but was fiddly - it involved getting into the front of the lantern and soldering at a steep angle due to the case being in the way. Didn't appear to be an easy way to get the whole kaboodle out of the case so just ran with it.

 

 

 

 

Hi Kevin, it always goes the way of half of the lamps so 3 go first and then others will follow in a batch i.e. the remaining 3 perhaps days or weeks later. And it is always the green element, no other colour at all fails....... just green.

I have had LED PARs fail on a colour channel due to the LED string driver chip failing rather than the chips themselves. Are all green LEDs out or just some of them (former could be the driver chip, latter the chip itself).

 

Kevin

[indyld]

My experience is that green LEDs are the most demanding. The green element of a chip can blow first, and also blow drivers. I verify the LEDs using a meter in diode mode which lights the LED very slightly.

 

Wired in series batches, a dead LED can obviously stop a whole cluster working.

 

Replacement is possible if you can get the LEDs. I harvest them from old boards as it's often easier than trying to find the right ones and not have to buy 100s.

 

To replace them, I use a hot plate method and sometimes touch up with hot air or an iron.

Edited October 21, 2019 by indyld