Replacing ONE LED in Chauvet LED PAR64 Tri-B?

[microstar]

The green circuit went out on one of my Chauvet LED PAR64 Tri-B fixtures. It has a total of 18 3-watt RGB LEDs and each color has 3 groups of six LEDs in series. Using a VOM I determined that the #3 LED in one string of six was bad. What’s odd is that the other two groups of green also don’t light so somehow they must all be in series..... The red and blue elements in the same LED chip work fine. I’ve isolated it to the LEDs by substituting driver board, etc., from another unit. Anyway, I can’t afford the $214 replacement cost of the entire LED assemby, so rather than try to desolder the SMT LED and find a matching replacement, can I just jumper across the bad element, or put an ordinary diode across to give some voltage drop? I’m thinking whatever I do can’t hurt since it doesn’t work now.

 

[JD]

No. Voltage drop is higher than a standard diode, and jumping it would quickly take out the others in the chain. Try Chauvet support, although I doubt they will be of much help. The best bet is to try and figure out the actual LED manufacturer. It turns into more detective work than service work, but I have been down that road many times. (Serviced near 30,000 units before retirement, all fields.) If standard solder was used, carefully lift all six legs and pop it off. There may be other clues, such as an identifier on the back. The reason I say "standard solder" is a new process is being used by China-co in which parts are bonded by microwave. Standard "dip" solder usually leaves rounded lands. Even hot air leaves some rounding. I don't see any in that picture.

 

[microstar]

JD... thanks for the quick reply! Chauvet support was friendly but wanted no part in replacing the single LED. Since the red and blue circuits still work, the fixture is still of some use so am reluctant to destroy the chip without having at least a possible replacement. Will dig thru the Mouser catalog and try to find something based on appearance and 3-watt RGB spec. Guess bridging with a resistor would require too large a wattage resistor to be practical?

 

[lightman02]

Have you tried just re-touching up the solder joint, you never know, could be just a cold joint?

 

[microstar]

The actual device leads are accessible and I measured across those, but thanks for the suggestion.

 

[JD]

Kind of looks like this guy:
3W rgb high power led with 6 legs used for led pool light, View led pool light, LEDGUHON Product Details from Guangzhou Juhong Optoelectronics Co., Ltd. on Alibaba.com3W rgb high power led with 6 legs used for led pool light, View led pool light, LEDGUHON Product Details from Guangzhou Juhong Optoelectronics Co., Ltd. on Alibaba.com

 

[JD]

Sorry about the two images!
Anyhow, the part number is JH-1RGB14G30
When I googled it, several sources came up where you wouldn't have to buy 500 !

 

[microstar]

Bought 10 at $1.81 each and should be here in two weeks. Thanks!

 

[microstar]

Just a followup on this situation....

Following JD’s discovery of the individual 3-watt RGB LED’s available from several Chinese vendors, I ordered 10 of them from kingfull-electronic-company on Ebay for a total of $18.13 including shipping. They arrived in 11 days and looked exactly like the LED’s in the fixture. It was a little bit of a chore to pry the 6 leads off the board as I unsoldered them but was doable.

I thought the LED would just plop off when all the leads were free but this was not the case. It took working a thin knife blade back and forth between the board and the bottom of the LED before the LED flew off. There appeared to be a crystaline substance holding it on, which looked like superglue. It was definitely not heatsink grease. Does anyone know if superglue conducts heat? I checked the new LED to make sure it worked.

I did not use anything to secure the replacement LED in place (possibly a mistake) and soldering the 6 leads was far easier than removing them. I checked for any solder shorts and put thngs back together, fired it up, and everything worked perfectly! The RGB colors even matched. I will burn it in on the bench and keep an eye out for any problems.

Many thanks to JD for his research and encouragement.

 

[VCTMike]

The LED could have been attached with something like this:
Thermally Conductive Epoxy Adhesives | MasterBond.com
LED Thermal Interface Materials | AI Technology, Inc.

These might be a good substitute if you find heat to be an issue:
Thermally Conductive Interface Tape :3M US
Thermally Conductive Adhesive Tape for High Power LEDs

 

[microstar]

Many thanks for the suggestions. Next time I will use one of the adhesive tapes.

 

[Jay Ashworth]

There is also an adhesive with silver particles in it used for gluing heatsinks to computer CPUs which might be useful there.

Sent from my SPH-L720

 

[JD]

SMD devices are often glued to the board to keep them in position while the board is flash soldered. In the "old days", components had leads which went through holes in the PCB and these leads kept the components in place. Without leads, glue is used. Also, a cream of emulsified solder is often applied to the circuit lands so that hot air can be used to solder them as compared to the older conventional solder dip process. On very high density boards, solder dipping doesn't work as the space between leads is close enough to create wicking. The new method turned out to be so successful that it is rare to see solder dipping used on modern equipment. The current trend is to replace the hot air method with microwave soldering. This new method uses a different chemistry and can be hard to service.

Hot air:

Ichiban Precision Sdn Bhd - Hozan - HOZAN HOT AIR STATION

 

[Orthas]

any luck with this?
I have 2 of these units and both have now given up the ghost with the green lights, one unit is a 3rd of green never work and the other 2/3rds flicker on and off and on the 2nd until its the same but 2/3rds never work and 1/3rd flicker. its a pain in the bum they were both sale units with only 3 months warranty and this happened between 18-24 months, I thought they were supposed to last 100,000 hours pfft

any way im very interested to know how you got on with yours

thanks

 

[mtongnz]

I have a bunch of similar fixtures (ColourDash Tri-18) and the green seems to always be the one to die. I managed to get some replacement LEDs from Chauvet after pestering them for a while and buying some other parts. They only had a few so when I ran out, I ordered some chinese LEDs. I changed all the LEDs on one light for chinese LEDs and use the harvested LEDs to repair the other lights.

The easiest way to do the repair is to remove the LED board from the light completely. Then heat the LED from the underside of the board using a heat gun for about 30-45 seconds and the LED will come off (I use tweezers). Before letting it cool, place the new LED. You might need to apply a bit more heat to melt the solder if you took too long placing the LED. I usually clean off the heat compound and apply new stuff to ensure there isn't any dirt trapped in there.

This method ensures the LED sits flat and bonds to the board correctly. I always mark the LED replaced so I know if its a specific issue recurring. I haven't had to replace the same LED twice in the past 2 years so it seems to work well.

 

[Jartin]

Sorry about the two images!
Anyhow, the part number is JH-1RGB14G30
When I googled it, several sources came up where you wouldn't have to buy 500 !

Hi I'm new to all this, I went to the site that you had recommend, but while searching it led me to around 60 search results, is there a certain model at the end that would lead me to a particle one? say for instances JH-1RGB14G30-S2A, would this be what I'm looking for?

 

[JD]

The picture I posted in 2014 is no longer the picture being displayed. (There was no mounting PCB.) It was more like the JH-1RGB14G38-S2A
The problem is, the Chinese will make a few million of something, and then move on to something else that is slightly different. You might be better obtaining one through Ebay or a parts distributor, even if you are paying more for it.

 

[ChrisW]

My PAR64 Tri B's have loosing their green one by one I now have 4 with no green . I Just picked up this thread a few weeks ago. I have now got some replacement LED's from China and removed the led board from the fixtures. How do I identify which LED is faulty when they are all still soldered to the board?

 

[JD]

My PAR64 Tri B's have loosing their green one by one I now have 4 with no green . I Just picked up this thread a few weeks ago. I have now got some replacement LED's from China and removed the led board from the fixtures. How do I identify which LED is faulty when they are all still soldered to the board?

A 9 volt battery in series with a 1.5k resistor will put about 6 milliamps through it, enough for a glow if it is good. Remember, polarity matters so it won't glow if it is reversed. Also, there are 3 circuits on the chip, one for each color. Don't do it without the dropping resistor.
pin-out can be found here- https://www.aliexpress.com/item/Epi...1817072032.html?spm=2114.40010308.4.90.i5M4yn
Sounds like the lights may have a bad batch of them. Again, you are looking for a JH-1RGB14G38-S2A but there may be plenty of substitutes.

 

[ChrisW]

That's great thanks for your help. I will l let you know how I get on.
Chris