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FrozenGate by Avery

Help request for replacing a laser diode assembly

Joined
Dec 31, 2008
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Hi, new user on the forums here asking for a little help on how to proceed with getting my mobolazer back in action.  The mainboard has a +/-3V output to the laser head, the existing laser is a 532nm green laser.  A photo of the disassembled laser head is attached.  The two rightmost items are threaded set rings, the left one seats the diode assembly into a ? (I don't know what the function of black and silver unit is) and the right one seats that whole assembly into the barrel.  The long barrel has a glass tube looking structure on the end, and the short barrel at the far left has a lens assembly in it.  So I'm trying to figure out what the best way to ressurect this would be.  Also I'm trying to figure out what parts I should try to reuse.  Thanks for any help anyone can provide.
 

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Re: Help request for replacing a laser diode assem

Don't know how to attach multiple pictures to a single post, so here is a more detailed pic of the black/silver unit.
 

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Re: Help request for replacing a laser diode assem

And a closeup of the long barrel end.
 

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Re: Help request for replacing a laser diode assem

john_lawson said:
thats your crystal set i believe if that wasn't taken apart you may be in luck
wheres the driver board

Hey, thanks for the reply. As far as I know the driver board is built into the mainboard of the overall unit as there is only a wire that goes from it via a three prong connector (center pin no connection) to the laser head, and in the back of the head there were two wires which connected to the two prongs on the back of the diode.  I checked the mainboard output with a voltmeter and it outputs +/- 3V (I didn't pay attention to the exact voltage but it was slightly more than 3V).

As far as the pieces being apart, the short and long barrels screw together, and the black/silver unit slides into the open end of the long barrel until it stops and is held in place by the larger "O" shaped piece on the far right of the first photo.

Would you think the crystal set is the black/silver unit or the whole thing?
 
Re: Help request for replacing a laser diode assem

thats your crystal set i believe if that wasn't taken apart you may be in luck
wheres the driver board


EDIT i tried to modify my reply and deleted it sorry

that last photo looks like the lense end  it goes under the collaminateng  lenses

now i'm lost you need to show whats in the silver and black piece Sorry :P
 
Re: Help request for replacing a laser diode assem

john_lawson said:
now i'm lost you need to show whats in the silver and black piece   Sorry  :P

Well, here's the other angled view of everthing lined up as it goes back together.

The nearest end of the short barrel has a square "lens" over it, perhaps IR filter? and is knurled like you could take it off, but it did not turn easily so I did not force it.  The hole in the center seems to be threaded as well.  The back side of the short barrel has an exterior thread that screws into the long barrel which is shown in picture DSC00008 above.  Approx. in the middle of the SHORT barrel there is a "stop" with a lens in it.

The near end of the long barrel is as you see it in DSC0008.  The far end of the long barrel is open and interior threaded up until a hard ring stop about 1/2" in, beyond that (about 3/4 of the way down) there is a brass colored "wall" with a square hole in it that has some sort of filter or lens in it.

The near end of the black/silver assembly has two dimples as if you could use a tool to rotate the disc, which I think is held in place by the set screw on top as you can see in DSC00003.  It also has some form of lens or filter in it.  There is a glass cylinder glued between where the diode sits and the silver unit.  I'm not comforable with disassembling the parts of this assembly yet, other than having removed the diode from the back, which is held in place by a screwed in "O" shaped holding ring.

Hope that description clears things up better.
 

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Re: Help request for replacing a laser diode assem

yea ok it looks like your crystal set but i wish one of the masters would speak up here
Kenom-Dave-Gooey-Ace -Igor - Rog ;D just to name a few
 
Re: Help request for replacing a laser diode assem

I am not seeing a drive circuit anywhere in the photo's, I assume you still have it?

If so you will need to connect it up to the LD, power it up and see if that part works....
Warning! that is a high powered infra red LD it will damage your eyes if you look at it when it is working, you need to view it through a camera phone or night vision camera/scope.

If the LD works you will need to get it pressed back into its housing in exactly the right position, in conjunction to the crystal.....  That is the really hard bit.

Find out if the LD is alive and get back to us.

Regards rog8811
 
Re: Help request for replacing a laser diode assem

The black and silver part is the crystal set. DO NOT take the crystal assembly apart! As long as it stays intact then the alignment should stay relatively correct. In order to get this assembly working again, all you should need is a replacement diode (as long as your driver is working properly). You'll need a 9mm 808nm open-can with a similar power rating as the original.
 
Re: Help request for replacing a laser diode assem

john_lawson said:
yea ok it looks like your crystal set

I guess I'm just trying to figure out how this all works. I've come across all this terminology as I've looked through stuff for a couple of days now trying to figure this all out, but I don't really understand how it all applies to the hardware in my hands. For example, is the crystal set just the black/silver part or the whole thing? Is it "matched" in some way with the diode? Does the actual diode output only IR and then the glass cylinder is where it converts to visible green? Is there a collimater in here somewhere? So basically, I'm just confused, it seems like it would be simple enough to just replace the gold colored diode unit and have it all work again, but maybe reality isn't that simple. Or could I use one of those blue/violet diodes from a HD player (I think I would need a different driver, but they seem pretty simple to build). But if I did that, what parts would I still need to use? Sorry to ramble, but this is all somewhat confusing, but I'm very excited to delve into it.
 
Re: Help request for replacing a laser diode assem

rog8811 said:
I am not seeing a drive circuit anywhere in the photo's, I assume you still have it?

If so you will need to connect it up to the LD, power it up and see if that part works....
Warning! that is a high powered infra red LD it will damage your eyes if you look at it when it is working, you need to view it through a camera phone or night vision camera/scope.

If the LD works you will need to get it pressed back into its housing in exactly the right position, in conjunction to the crystal.....  That is the really hard bit.

Find out if the LD is alive and get back to us.

Regards rog8811

This is out of a mobolazer beam table, so I belive the drive unit (which is basically just a stable power output device, yes?) is part of the main motherboard, which I have checked and is outputting 3V. Or am I missing something in between the 3V output and the LD?
 
Re: Help request for replacing a laser diode assem

ElektroFreak said:
The black and silver part is the crystal set. DO NOT take the crystal assembly apart! As long as it stays intact then the alignment should stay relatively correct. In order to get this assembly working again, all you should need is a replacement diode (as long as your driver is working properly). You'll need a 9mm 808nm open-can with a similar power rating as the original.

I guess that would be another of my questions. Could the drive unit be part of the mainboard, does it just output stable power, or is there something I'm missing between the 3V output of the main board and the LD? Also, do you have a recommendation for where to pick up a LD with the specs you listed?
 
Re: Help request for replacing a laser diode assem

I guess I'm just trying to figure out how this all works.  I've come across all this terminology as I've looked through stuff for a couple of days now trying to figure this all out, but I don't really understand how it all applies to the hardware in my hands.

 For example, is the crystal set just the black/silver part or the whole thing?
The crystal is the little glass bar in the middle of the silver and black bit

 Is it "matched" in some way with the diode?
very much so, it has to be at exactly the right position to excite the crystal

Does the actual diode output only IR
yes

and then the glass cylinder is where it converts to visible green?
yes

 Is there a collimater in here somewhere?
yes, somewhere buried in the front end

 So basically, I'm just confused, it seems like it would be simple enough to just replace the gold colored diode unit and have it all work again, but maybe reality isn't that simple.  Or could I use one of those blue/violet diodes from a HD player (I think I would need a different driver, but they seem pretty simple to build).  But if I did that, what parts would I still need to use?  Sorry to ramble, but this is all somewhat confusing, but I'm very excited to delve into it.
You could reuse the housing for another colour LD, you would need to play with the optics to see what works

Regards rog8811

[edit]The pictures below may help show the complxity of the laser[/edit]
 

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Re: Help request for replacing a laser diode assem

MTWallet said:
[quote author=john_lawson link=1230744297/0#6 date=1230747877]yea ok it looks like your crystal set

I guess I'm just trying to figure out how this all works.  I've come across all this terminology as I've looked through stuff for a couple of days now trying to figure this all out, but I don't really understand how it all applies to the hardware in my hands.  For example, is the crystal set just the black/silver part or the whole thing?  Is it "matched" in some way with the diode?  Does the actual diode output only IR and then the glass cylinder is where it converts to visible green?  Is there a collimater in here somewhere?  So basically, I'm just confused, [highlight]it seems like it would be simple enough to just replace the gold colored diode unit and have it all work again[/highlight], but maybe reality isn't that simple.  Or could I use one of those blue/violet diodes from a HD player (I think I would need a different driver, but they seem pretty simple to build).  But if I did that, what parts would I still need to use?  Sorry to ramble, but this is all somewhat confusing, but I'm very excited to delve into it.[/quote]

It should be as simple as that. There's only so much that can go wrong in a laser of this type. As long as your crystals aren't tampered with at all, then the only other part that can be bad is the diode. The collimating optics would have been focused at the factory, so as long as you replace the diode with another identical one and reassemble the unit exactly as it was before it was disassembled, then the unit should work again.

As I said before, you need a 9mm open-can [highlight]808nm[/highlight] diode with the same power output as the original. In order to determine how powerful the diode should be, I'd need to know how many mW of green that the module is supposed to output when fully assembled.

The graphic in rog8811s post above will really help you understand how green DPSS works.
 
Re: Help request for replacing a laser diode assem

ElektroFreak said:
I'd need to know how many mW of green that the module is supposed to output when fully assembled.

The graphic in rog8811s post above will really help you understand how green DPSS works.

Well, he said complexity and that certainly applies to that graphic! :D

The original output was 5mW.

Thanks so much you guys, the last 20 minutes of communication has far more helped my understanding that the last two days of reading!
 
Re: Help request for replacing a laser diode assem

5mW of green output usually requires a 200-250mW pump diode. This is due to the fact that the process of generating the green output is 20-30% efficient at best.
 





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