Old Olight SR90, upgrade to SBT90.2?

cujet

Newly Enlightened
Joined
May 30, 2005
Messages
27
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Florida
My old SR90's SST90 LED was losing performance and then simply fell off. It got so hot the solder melted. I sent it back for repair, and Olight did solder the LED back on, only to have it fail the same way again, within minutes. I like the light, despite it's size, as it runs on High for a long time. Long enough to get the various animals off of the runways at the local airport.

I've been thinking about simply installing the similar 3.2V, SBT90.2 emitter and trying to use the original drive circuitry. Probably simply purchase an emitter already attached to a MCPCB and simply screw down the heat sink as there is plenty of room. $25 from Alibaba... Or $50 from HI.

Has anyone done this?

Thoughts?

SBT90.2.jpg
 
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cujet

Newly Enlightened
Joined
May 30, 2005
Messages
27
Location
Florida
Here is a picture of the LED before it fell off due to overheating.

Years ago, Olight repaired the light with (I think) a new LED. However, it fell off again.

I'm going to order a SBT90.2 from Alibaba and driver. I'll try it.

2qA8kjJl.jpg
 
Joined
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If the original emitter fell off due to heat, perhaps the (poor) thermal management allowed it to get hot enough to damage that part. Wouldn't the same happen to an SBT90.2?

Also, that photo of the original emitter looks like there's a dark spot on the phosphor. Was it burning out?
 

cujet

Newly Enlightened
Joined
May 30, 2005
Messages
27
Location
Florida
If the original emitter fell off due to heat, perhaps the (poor) thermal management allowed it to get hot enough to damage that part. Wouldn't the same happen to an SBT90.2?

Also, that photo of the original emitter looks like there's a dark spot on the phosphor. Was it burning out?
Yes, the LED was failing prior to falling off. The perceived brightness declined by 75% AND it was producing a big donut beam. When new, the thing was perfect. In my estimation, the light lasted about 30 hours of use. When in use, it was generally on for drives around the airport, and down the runways, Often for many minutes per use.

I "think" the thermal pathway was acceptable, as it was a pretty much a large, solid chunk of brass, and a tight fitting, brass 26mm disc to which the LED was directly soldered and plenty of thermal compound. I did not alter or disassemble the light prior to failure. The LED discolored, the performance declined, and eventually it failed.

Quote from Lumileds:
"Based on the pictures you sent it appears that the emitter in your system is an SBT-90. It also appears that it is exhibiting a transitory issue that we have encountered previously. What is likely occurring is some volatile organic compounds (VOCs) have found their way onto the surface of the LED die. There can be a number of causes for this, very often due to outgassing of adhesives in the system. Paradoxically the resolution to this issue is usually simply running the LED for more hours. 30 hours is a very small number of hours for the SBT-90. I would recommend running your light continuously for a few days at maximum brightness.. This will "burn off" the VOC's and the emitter will return to normal use."
 
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