How to remove star

vicv

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I believe this is glued down with some type of thermal adhesive. This is an older solarforce brand .9-4.2V p60 drop in with an xpgr5. It's quite blue. I bought an sst-20 4K for it. This light usually has a xenon in it, but I thought I'd update this drop in. It doesn't ever get used due to the colour. Is there a way to soften this adhesive to remove the star? And if so do I need adhesive again to install the new star? Thanks

I could easily buy a new pill, reflector, and driver. But these low voltage drivers are hard to find. Not that I need it it'll be run of a single 18650. But if I can swap this emitter, I'd like to
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Duster1671

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Can you take the driver out so that you just have the pill and star?

If so, a strategy I've used, though not ideal, is to drill a small hole through the pill from the backside, just deep enough to break through the brass, and then use a small pin and a hammer to punch the star out.

You might even be able to do this without drilling a hole, since the corner of the star is overhanging the hole for the negative wire by a bit. Actually both holes look like they're partially covered. Those could be good spots to pry on the star from the top side, too.

Whether you need to glue it down again depends on how the rest of the drop-in goes together. If the reflector threads on and pushes on the star with a centering ring, you should be fine with just regular thermal paste. You just don't want the star to come away from the pill.
 

vicv

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Ya the reflector does screw down and there is an insulating centering ring that came with the new star.
I will see if I can easily remove the driver. Thank you
 

louie

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I suspect you could pry off the old star with a good tool like a Wiha chip lifter, and chip out the adhesive. You have a replacement star? So you wouldn't care about damaging the old one, right?
 

sween1911

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You're good to go, this looks like a great host for an emitter swap.

1) Unsolder the two leads. Be careful not to put stress on where the wires connect underneath.
2) Put a screwdriver between the wall of the pill and the edge of the LED base and twist. It'll pop off.
3) After that, grind/pick/sand the rest of the white stuff off, clean it with a little alcohol, and put down fresh thermal paste before soldering down a new LED.
 

vicv

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Thanks. That's what I figure. I just wasn't sure how hard the adhesive would be to remove. Or if I could use heat to help. But if it just requires some mechanical pressure to pop it off that should be no problem. Now I will just have to find myself some thermal paste
 

kerneldrop

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I should solder the new LED?

Solder paste

Try to get as much of the epoxy off as you can... space is no good. Epoxy paste works by filling those tiny little voids.

That epoxy might just pop cleanly off....the bond is only as good as the surface and there's no way that surface was properly prepared for maximum adhesion at the factory.
 

louie

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I wouldn't bother trying to heat the gunk, it is unlikely to help and just cause damage to nearby parts like the driver. I bet it'll pop off.

Do you have a whole new star with LED attached, or do you need to reflow the new LED onto an MCPCB?
 

vicv

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Solder paste

Try to get as much of the epoxy off as you can... space is no good. Epoxy paste works by filling those tiny little voids.

That epoxy might just pop cleanly off....the bond is only as good as the surface and there's no way that surface was properly prepared for maximum adhesion at the factory.
Thanks. I would think solder paste would need quite a bit of heat would it not? I would probably need to remove the driver in that case
If the reflector will hold it in place, I'll probably go that route. I think this driver only draws about 1A on high. We'll see. I'll add a couple blobs of solder to the pill/star if needed
 

Duster1671

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I think sween1911 was probably just saying to solder the leads to the LED board. I wouldn't try soldering the MCPCB down to the pill. You're right that it would take a lot of heat and almost definitely require removing the driver. There's no reason to do it anyway, especially if the reflector will hold the MCPCB in place.
 

kerneldrop

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I'm not sure we are all on the same page.

How do you plan on connecting the LED to the star?

The LED emitter should be soldered to the star using solder paste.
The LED should be mounted to the star with the star outside of the "pill"...so the driver won't be a factor and doesn't need to be removed.

I use an electric skillet on 400 degrees with solder paste or a hot air station when I don't have a choice.
 
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kerneldrop

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I think sween1911 was probably just saying to solder the leads to the LED board.

Sween is saying to apply solder paste to the MCPCB's Cathode, Anode and Die Heat Sink, and then mount the LED onto MCPCB.
He's not saying solder the MCPCB to the driver pill.
 

sween1911

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Whoa whoa whoa, my apologies if I wasn't clear.... :)

1) Artic silver thermal paste between the back of the MCPCB and the pill when you stick it down. Make sure the red wire can reach the positive terminal and the black wire can reach the negative terminal. It's not like superglue, you can move it around after attaching it. It's just to allow heat transfer from the MCPCB to the base and to the body of the light.

2) When you attach the new LED, solder the red wire to the positive terminal and the black wire to the negative terminal of the new LED.

That's all the pasting, gluing, and soldering I'm saying.
 
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vicv

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Ok. I bought a luminous sst-20 4k mounted on a copper star.


C$ 6.36 | luminus SST20 SST-20-W high CRI specialty white LED 3000K 4000K 5000K 6500K on 16mm / 20mm DTP copper board

I'm going to remove the old mcbcp/emitter which is glued to the pill, desolder the + and - leads, and install the new star onto the existing pill while leaving the driver as is. I'll resolder the + and - leads to the new mcbcp/emitter, and use the insulator disk/reflector to hold it in place
 

sween1911

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Ok. I bought a luminous sst-20 4k mounted on a copper star.


C$ 6.36 | luminus SST20 SST-20-W high CRI specialty white LED 3000K 4000K 5000K 6500K on 16mm / 20mm DTP copper board

I'm going to remove the old mcbcp/emitter which is glued to the pill, desolder the + and - leads, and install the new star onto the existing pill while leaving the driver as is. I'll resolder the + and - leads to the new mcbcp/emitter, and use the insulator disk/reflector to hold it in place
Sweet! Let us know how you make out, buddy.
 
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