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Fixing “SMP” Sci-fi 1.8w 445nm laser. Where to start?

Nvloc

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I’ve had this laser sitting in a ziplock bag for a couple years waiting for the time to figure out why it stopped working. I don’t remember why or when it no longer worked. It worked a couple dozen times over the course of a year and then one day nothing...

Where to start. Assuming it could be several different components. I’m sure at some point after it stopped working I would’ve switched the polarity of the batteries.

It has a 5.6mm m140 diode. And a type of “buck” driver?
I will begin by testing ohms on the switch, as far as testing the diode or driver I don’t think I have the tools to do so.












 



BowtieGuy

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Just curious, did you happen to purchase this laser from an ex member named "Joker", this looks a lot like his work?
If you have switched the battery polarity, you probably have killed your diode, or at least the driver.

Edit - Nevermind, I see in the title that it is a Sci-Fi laser, I guess that I should read closer.
 

Nvloc

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Yup bought it from Eitan. Early/mid 2015, was a classic mess dealing with him.
This was a sorry shipment based on a crappy first purchase.
Got a really good deal in the end though, only charged me $100 including shipping for this

Best plan of action just buy a new diode and driver?

There may actually be a design flaw in the host. Both surfaces where the bottom and top PCB board mount to the host the diameters don’t really allow the outer contact surfaces to mate very well. May need to create a little shim adaptor. That’s if they’re supposed to make contact and utilize the host itself as the ground connection at either end...?
 

GSS

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Can you send a pic of the host? Just curious as it doesn't seem to be a 501B
Most likely it isn't a M140 either or if it is it may have alot of hours on it, as at the time these weren't that cheap yet and found out my 501b from him with the claimed M140 had no markings what so ever. Most likely a driver meant for a LED also.
Yup your best plan is what you mentioned an also get a copper module instead of the plated brass one you have now..
Just when I think Eitan's poison has left the forum, they still pop up:(
 

BowtieGuy

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Yeah like GSS said, or probably even better yet would be to just get a complete new laser, Lifetime17 makes some nice custom units for reasonable prices, or there are some that come up in the BST section frequently.
 

Nvloc

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This is the host. I had a local guy test the output of this when it arrived. Can’t remember the exact number but was 1.8w give or take a bit

 

Nvloc

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It would be a shame not to get this running again, it’s a pretty skookum unit
 

BowtieGuy

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That host has seen some better days, so yeah, I think that unless you really like that host, I'd replace it rather than repair it, not saying that it can't be done, but I think you'd be better off with a new high quality build.
 

GSS

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The AL host looks kinda thick and that's a nice piece of copper up front.
Polish it up and it will be nice, especially the copper. Maby even get a custom focus knob from Rich:)
Bowtie and Rich have some nice way's of getting really nice sheen. This way you also get the satisfaction of having a working unit of what you initially ordered..
 

Nvloc

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Sorry I guess I should probably just scrap this thing after reading how much of a total douche Eitan is/was...But I never throw anything away that can be fixed

Still not perfect due to some slight pitting in the Aluminum. And don’t have a bench top polisher yet so this was done by hand.



GSS. If it isn’t an M140 diode then what would it be? And an LED driver? Elaborate?
I’d love to support more people in more hobbies by just buying a new build from someone... I have wayyyy to many hobbies to get into lasers, this is just a buy one and have one, barely a hobby type thing

Just here for a bit of guidance on how to get this running if that’s ok?

Are diodes on eBay USED and the ones on survival lasers NEW? And what is the specific type of driver to replace this with. Sounds like I should get both...
 

Nvloc

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Disregard this thread for now! Just put the guts together on the workbench hardwiring the outer ring on the rear switch to the negative side of the diode, pushed the button and it lit up!
So it’s either a flawed contact at the butt end where the switch is supposed to ground to the host or the driver is bad.
Back to the workbench
 

BowtieGuy

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Looking real good with the hand polishing; glad to see that it lives!
It could be the tail switch or it's contact to the host; also, be sure that the spring at the switch end is making proper contact, it looks like it has a funky bend to it.
 

paul1598419

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I have a few of those hosts. I put one of my NDB7675s in one of them. It is really not a bad host. The build quality is very poor, so I would change some things out like already suggested, but that host is not bad at all. The aluminum walls are quite thick and the copper heat sink weighs about 6.3 ounces, IIRC. It will take either a single 18650 battery or two 16340s.
 

Lifetime17

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Hi, Yup looks like the Jokers work and handy soldering tactics, This guy is like a bad penny keeps appearing . I repaired quite a few of his abortions in the past. its a hefty sink and solid host but he used cheesy components.

Rich:)
 

Nvloc

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Good call on the tail switch ground bowtie :)
The contact area of the pcb appeared to be too small to contact the body of the host. I ran a bead of solder around it but didn’t change the diameter really. Also added a goop of solder to the spring and filed a flat spot for a greater contact area. Plan b for the switch ground was to make little tabs protrude that would make contact. Success! It worked, but not for long. I took it apart again messed around with the seating of the diode as it appeared crooked. Then it’s stopped working.
Turns out I learned a lot today about how these things actually work, mainly that components need to be grounded to the host. I then realized the backside of the driver needed to be grounded to the host too. I guess he used a conductive glue which would’ve allowed a connection but I obviously broke that connection taking it apart.
I was going to solder the driver right to the copper head but changed plans in case it needed to come apart again so used the same idea as the switches PCB and soldered tabs there too (don’t mind the gobs of solder on the copper)

Progress...












Maybe these pics will help someone else fix one of these or learn something.

Next step is correcting a flat beam. I remember having this issue before and not sure if it’s the type of lens used?
 
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