SST-90 Remove from star?

[Olef]

I searched before posting but could not find any definite info so -

I'm looking at buying an SST-90 from Avnet. I've found this part number - SSR-90-W65S-R11-GN100 which I believe is a 6500K high flux bin emitter. Only problem is it is mounted on a star PCB and Avnet do not have the bare emitter in stock. I'm planning a 4D Mag mod with this and looking at the heatsinks available hereabouts I need a bare emitter.

So how hard is it to remove an emitter from a star reliably? I say this as the part is almost £30GBP so a single failure would be very costly to me. Is it worth having a go at or is it better to wait for the bare emitters to become available and not risk it?

I know how to use a soldering iron and have a temp controlled station but I am new to optoelectronics and SMD's.

Any guidance would be much appreciated

Olef

 

[Linger]

Don't do it. This only has merit as a thought exercise and if the point of your question is to actually get a rugged and usable tool (the modified light) then there's no point messing around with the starting component when you don't have too.
Even if you were 'expert' at this process it would mean twice more thermally stressing the emitter (to desolder then resolder when you hook it up) which introduced a lot of risk and possible degradation that can be completely avoided.
Call Avenet, apparently their people are very helpful and their website is not at all reflective of actual stock levels.
Also try posting a want to buy (WTB), someone might have an extra

 

[Drywolf]

I'm not sure a soldering iron will do it. I have a 140 watt weller and I tried it, but it would not come loose. I used a propane torch and it worked fine. I held the star I bought from Avnet in a vise and passed a torch over the back, back and forth until it came off with a little help of a hobby knife. I'm not sure if I damaged the LED or not, but it works to my satisfaction.
Frank

 

[Olef]

Thanks both, I take the point that the extra heat / cool cycle may not be good for the longevity of the emitter and I must admit to being pretty reluctant to cook one up with a gas torch. Guess I'll talk to Avnet and wait if that is necessary.

Olef

 

[Linger]

you've got to get someone taking pics if you use the torch...

 

[Drywolf]

you've got to get someone taking pics if you use the torch...

Torch was being used on minimal setting. The LED is installed and working fine.
Frank

 

[tx101]

I used the same method as Drywolf it does work but you need
to be very careful. Keep your eye on the emitter and heat it up
slowly. Use a small screwdriver or something to GENTLY push
the emitter off the board but DONT force it.

 

[moviles]

the sst-90 its too delicate and fragile for me and it is hard to use thick wires with the SST-90

I prefer the sst-90 with star (SSR-90)

why not some mod like the pepko mod with SSR-90?

 

[Olef]

the sst-90 its too delicate and fragile for me and it is hard to use thick wires with the SST-90

I prefer the sst-90 with star (SSR-90)

why not some mod like the pepko mod with SSR-90?

Now that would be perfect for my first mod! Unfortunately I do not (yet ) have machining facilities other than a Dremel and the only heatsinks I have found so far all need a bare emitter.

Olef

 

[Paul Baldwin]

Hi,
I've been using a jet lighter instead of a gas torch.

4/5 seconds is enough to melt the solder and then just gently push the emitter off the star. Very easy to do but that is 30 quids worth!

Paul.

 

[bshanahan14rulz]

Paul, I have that same "helping hands" setup for holding small parts!

Seriously, though, those jet lighters get way hotter than most lighters. I've used them to melt glass as thick as microscope slides (not the thin coverslips, but the thicker glass you put the sample on). They even melt pennies (but I haven't tried that and would never endorse it, it's illegal to deface government property...)

 

[Paul Baldwin]

I'll find a proper pair of helping hands one of the days, glad I'm not the only one! lol
I know what you mean about the heat, my model is the 2000C, probably over the top. It is adjustable tho, I experimented with a faulty Cree I had and found that on the lowest setting that the lighter lights held pretty much as far away as in the photo (maybe further) it's ok? I've not seen any evidence of damage so far anyway after removing and replacing several After doing a couple you can pre-empt when the solder is going to melt and release the lighter before it actually does, I just gently waft it underneath the star.

 

[PMM]

removing with blowtouch has merit esp if emiiter part is able to just drop off.

That said I've worked with the bare emittors and have already lost 2 lenses during the soldering process.

3rd one I was using freezing spray on the Len's before & asap after soldering.

The next 2 on there way to me are on Stars lol.

Also the PCB on the bare emittors is extremely fragile as well, I used some solid core wire on one 1mm to 1.5mm and on some fine adjustment the PCB snapped in half.

 

[Drywolf]

I found a much better way of removing and soldering LEDs to and from stars. I bought a small 8" cast iron skillet and then I hold the LED with a large alligator clip with wire attached as a handle and the flame on medium high. Once the LED and star reach the right temp it is simply lifted off the star. I'm sure other hot plates work just as well, but I wanted a small pan for frying two eggs. So for the frying egg part, here is a tip (pan). Use a sander to get rid of the top layer of the cast iron until it's mostly silver in color and you will have the perfect pan for frying eggs without using teflon ( just a quick squirt of pam).
Thanks,
Frank

 

[AnAppleSnail]

That said I've worked with the bare emittors and have already lost 2 lenses during the soldering process.

3rd one I was using freezing spray on the Len's before & asap after soldering.

Preheat the LED to remove moisture. Hold it at about 150F for about 5 minutes and you draw moisture out of the dome. That's nowhere near damaging temperature.

 

[SmurfTacular]

I also need to remove the star from this emitter. Is their solder between the LED and the star board? Or are just the tabs soldered to the star?

 

[joohn]

You can buy the sst-90 bare without the star; I purchased 4 from Germany last year. I will try to find out where.
joohn

 

[Walterk]

Hold the star angled, put lighter underneath and tap it of when you see the solder get fluid.
Otherwise get another at led-tech.de