Synrad / Laakman 10W CO2 Laser...

Hi Everyone,
As some of you may know. I purchased a couple of these tiny RF pumped CO2 lasers at a local swapmeet last week.

Well, I just started reassembling the power supply for this laser and having no experiance with RF supplies,,, I have a few questions. Here are a few pics of the laser head with the RF amplifier I just installed along with the RF pre-amplifier/modulation board.

http://i512.photobucket.com/albums/t...2/P4131919.jpg

http://i512.photobucket.com/albums/t...2/P4131925.jpg

So, I installed the RF amplifier board onto the laser head and used solid copper wire to run the connections along with covering the sharp connections with hot glue to keep the RF from dissipating.

http://i512.photobucket.com/albums/t...2/P4131924.jpg

http://i512.photobucket.com/albums/t...2/P4131923.jpg

Here are my questions.....

It seems I need a fuse on the board that powers the large MOSFET amplifier. What is the value of this fuse supposed to be?

Is the input on the amplifier power board +12VDC?

Is this where the pre-amplifier RF signal goes?

http://i512.photobucket.com/albums/t...tuff2/CO21.jpg

Here is the pre-amp board. I'm guessing I need +12VDC for the modulation for full on. Is this correct?

What is the other input and voltage? Is this an interlock or something?

http://i512.photobucket.com/albums/t...tuff2/CO22.jpg

Here is the other end of the board. I'm guessing the main power for the board enters here as +12VDC and the RF output exits via the BNC connector and connects directly to the laser head amplifier.

http://i512.photobucket.com/albums/t...tuff2/CO23.jpg

Any help would be greatly appreciated.
Thanks!
Adam

Eh, there is something wrong here. One the RF amp board needs a heatsink for that big RF transistor. They only last a few microseconds if not heatsinked right, There should be a scrw sticking out of the transistor for the heatsinking, or some form of mounting bracket on it. Two, the "preamp"board is something else, as the coax should go straight to the matching network,

I need more pics of the RF Feed end of the tube, the little board you call a preamp (both sides) and some time to figgure this out. Yours are a far newer genration then mine is.

Steve

I think dar303 has one of these. Let's hope he can shed some light on it when he finds the topic. Or you can try sending him a PM to get his attention. :)

Quote:

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Originally Posted by mixedgas

Eh, there is something wrong here. One the RF amp board needs a heatsink for that big RF transistor. They only last a few microseconds if not heatsinked right, There should be a scrw sticking out of the transistor for the heatsinking, or some form of mounting bracket on it. Two, the "preamp"board is something else, as the coax should go straight to the matching network,

I need more pics of the RF Feed end of the tube, the little board you call a preamp (both sides) and some time to figgure this out. Yours are a far newer genration then mine is.

Steve

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Hey Steve,
Yes, I was definitely planning on putting a heatsink on the RF pre-amp transistor. Yeah, the "pre-amp" board was cut from a larger PCB so I have no clue if it is the original equipment or not. My guess is that the head had a BNC connector on it at one time and has been removed at some point.

The two boards on the head were put there by me since they looked like their original/logical location. I may be wrong though. Anyway, I'll take some pics and post them before I leave. Thanks a lot for your time.

Quote:

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Originally Posted by tocket

I think dar303 has one of these. Let's hope he can shed some light on it when he finds the topic. Or you can try sending him a PM to get his attention. :)

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Hi tocket!
Thanks for the info. I'm sure I'll get this little CO2 running between the knowledge of Steve and dar303. I'll send him a PM.
Thanks!
Adam

Here are some more detailed pics for ya Steve. Let me know if you need pics of anything more specific. I can also draw up a schematic on the main amplifier portion if you need it.

http://i512.photobucket.com/albums/t...2/P4131929.jpg

http://i512.photobucket.com/albums/t...2/P4131930.jpg

http://i512.photobucket.com/albums/t...2/P4131931.jpg

http://i512.photobucket.com/albums/t...2/P4131932.jpg

http://i512.photobucket.com/albums/t...2/P4131933.jpg

http://i512.photobucket.com/albums/t...2/P4131934.jpg

http://i512.photobucket.com/albums/t...2/P4131935.jpg

http://i512.photobucket.com/albums/t...2/P4131936.jpg

Sorry, I didn't buy one of these since I already had a Synrad 48-1...but I did tip of a few other people on a Swedish electronics forum of these lasers and I know that a few bought lasers.
I'll tell them to pop in here and take a look!

I am one of the guys that dar303 did tip of these lasers, but i bought the complete package with the original drivers so i am unfortunatly not able to help you with that one...

I know that the one of the other guys on the same forum as me and dar303 also bought the complete package and not this option...

The other guy, that would happen to be me, can't help you either since I have a different driver/amplifier but I advice you to contact Chris Leubner (heuurscience @ laserpointerforums) assuming you bought it from him. There was a laser/HAM-swapmeet in Waukesha, Massachusetts (EDIT: brainfreeze. I meant Wisconsin) a few days ago if I'm not mistaken and word is that Chris was there so chances are high you bought it from him...

Good Luck, I'm sure you'll get it up'n'running!

Regards,
Tottish

I may be mistaken, but it looks like you have a Class E Rf amp (that big FET) bolted to the laser heatsink and a seperate class C rf amp on the board. Do you have a ham radio operator friend nearby, that has a RF wattmeter ?

It also looks like someone bandsawed off just the amp, that may or may not be a problem.

I still cant see enough details of the matching network on the laser head that couples the RF into the tube, some of what I need to see is buried.

It certainly does not look like the matching network on mine, although my tube is the same.
I've never seen mine run, the guy I sent the RF amp to repair it never sent it back. I could have, and should have, done that repair myself.. I have the RF gear to do it.

BTW< the RF is channeled for 27.120, and cb channel 14 is 27.125 Mhz. You want to jam some CBers, it looks like you have about 20-30 watts, and they have 4 max.

So I'd make sure your not radiating, least 4 biker dude truckers want to bust down your door at 4 am.
If the tube lights, its adsorbing the energy and your not radiating that much.

Steve

Draht!

Steve

What the hell are you gonna do with 10W of CO2... :confused: Mix it with that Ruby? ;) Be an intersting optic. :rolleyes:

OK the fuse is 15A 250V fast acting, sort of odd package type one. The red and black are 36V at about 10A in 12V on board is 12V at about 5A or so, and the 5V input is 5V at about 300mA. The RF preamp board must be grounded and heat sunk or the medium power Rf transistor will fry. Make sure the RF power fet has a fully wetted solder connection and good ground/heatsinking to the laser tube or it will self-destruct

Quote:

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Originally Posted by mixedgas

I may be mistaken, but it looks like you have a Class E Rf amp (that big FET) bolted to the laser heatsink and a seperate class C rf amp on the board. Do you have a ham radio operator friend nearby, that has a RF wattmeter ?

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Yeah, I have an analog RF meter here that will go to 100W. Unfortunately i "had" some really good RF buddies but they both passed away. I do know a guy with an RF spectrum analyzer but he's over an hour away. I may use him for tuning my output when I get the laser up and running.

Quote:

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Originally Posted by mixedgas

BTW< the RF is channeled for 27.120, and cb channel 14 is 27.125 Mhz. You want to jam some CBers, it looks like you have about 20-30 watts, and they have 4 max.

So I'd make sure your not radiating, least 4 biker dude truckers want to bust down your door at 4 am.
If the tube lights, its adsorbing the energy and your not radiating that much.

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"Breaker, Breaker 10,600nm!" :D:eek::D

Quote:

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Originally Posted by allthatwhichis

What the hell are you gonna do with 10W of CO2... :confused: Mix it with that Ruby? ;) Be an intersting optic. :rolleyes:

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Burn stuff... What else! :D I've actually always wanted to own a CO2 to learn about them. I'm also gonna get a crash course in RF pumping which is cool as well. I'll probably get bored of them after I get it running.

Quote:

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Originally Posted by heruursciences

OK the fuse is 15A 250V fast acting, sort of odd package type one. The red and black are 36V at about 10A in 12V on board is 12V at about 5A or so, and the 5V input is 5V at about 300mA. The RF preamp board must be grounded and heat sunk or the medium power Rf transistor will fry. Make sure the RF power fet has a fully wetted solder connection and good ground/heatsinking to the laser tube or it will self-destruct

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Great! Exactly the info I was looking for. Do I have to feed the FET 36V or can I get away with 24-48VDC? Should I use heatsink compound between the FET and the laser chassis and, if so, should I use conductive paste or indium for a better ground?
Thanks Again!
Adam

The fuse socket is for a TR5 fuse. The largest fuse I can find in this package is 10A @ 250V. Any suggestions?

I did find this and it should work in place.... I think. http://search.digikey.com/scripts/Dk...&name=F2352-ND

10A 250V should work OK

Quote:

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Originally Posted by heruursciences

OK the fuse is 15A 250V fast acting, sort of odd package type one. The red and black are 36V at about 10A in 12V on board is 12V at about 5A or so, and the 5V input is 5V at about 300mA. The RF preamp board must be grounded and heat sunk or the medium power Rf transistor will fry. Make sure the RF power fet has a fully wetted solder connection and good ground/heatsinking to the laser tube or it will self-destruct

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Hi Chris,
Okay, I almost have this head ready to go. Tell me more about the 5V input. I see it runs to an opto-isolator. Instead of supplying the 5V, can I just defeat the circuit? If so, do you know how? Also, is the full +12V to the modulation full power or is it reversed? Can I run the FET on 20V @ 10A to just get it running? It should, Right?
Thanks!
Adam

Okay, I'm almost there.... I now have a BNC connector wired to the head with a coax running to the pre-amp.

http://i512.photobucket.com/albums/t...2/P4201937.jpg

http://i512.photobucket.com/albums/t...2/P4201938.jpg

http://i512.photobucket.com/albums/t...2/P4201939.jpg

I have the 12V @ 10A wired to the pre-amp main inputs and a small run to the modulation input. I also have 30V @ 10A running to the FET. I get the green LED light at "MOD OK" and a red LED light on the FET power board. Now I just need to get the "RF OK" light to come on. Supposedly I have to put +5V to the collector on the opto-isolator to the far right of the board to get it to work but it's not.

Any Suggestions?

Oh, Don't mind the tiny heatsink on the pre-amp. It's just there for short tests. I plan on putting a bigger one on once I know it is working.

The ground of the RF board should have a free flow GROUND connection to the laser tube chassis, if not back EMF will shut the pre-amp unit off to protect it.

Hey Chris,

Thanks for your reply. The ground of the RF board is the same as the ground on the laser head chassis as I'm using a BNC connector between them. The ground was also verified with an continuity check. Anything else I should consider?
Thanks!
Adam

I did a little research and it seems these lasers come in sets of seven in a Domino DDC3 laser coding system used to put lot numbers on products at high speed. They use 7 CO2 laser heads in a fashion, kind of like the solenoid head on an old dot matrix printer.

Here is what the RF driver boards kind of look like when they are in one piece (different amplifier). Now I see why they were cut up and individualized.

http://www.csldirect.com/images/35309.JPG

Now, If I could only get the damn thing to work! :D

Okay..... GOOD NEWS! I figured out What I was doing wrong. After looking at the "whole" RF driver board I noticed the 12V/5V computer type connector. Well, It turns out that 5V connection is needed! :D :o

I am now getting the RF driver board to create RF! However, new problem.....

When I turn on the FET power ( 30V @ Limited to 8A) The SMALL coil above the FET starts to heat up and smoke! (from the coating) :eek: I only had the circuit powered for 10 seconds or less and the FET PS says it's drawing around 2 amps. The laser does not appear to have any output either.

Any Suggestions?

Thanks!
Adam

http://i512.photobucket.com/albums/t.../SmokeCoil.jpg

The ceramic cap looks like it's touching the coil but it's not. It's actually about 1/8" away.

IT WORKS! :D

After taking Chris's suggestion of crushing the coil a little tighter, I got the tube to light! Makes Swiss cheese out of cardboard too! :D My whole lab stinks now.

Anyway, I measured the output. From a cold start, I get about 3.5W this slowly slopes down to around 2W after about 30 seconds of continuous output. I'm currently feeding the FET with 35V @ 10A but the FET only draws 2A of that.

Any chance I can get more power out of this little sucker? I tried further tweaking of both the large and small coils on the head. I just seem to loose power not gain any. The large coil could probably be crushed closer but not by much. The small coil is basically completely crushed.

Any suggestions would be greatly appreciated!

I'll post some pics of it running tonight. Maybe some video too.

If it lights you have the circuit in resonance, but for fine tuning, You may be able to adjust the ferrite tuning slug in your pre amp board in the can on the OUTPUT SIDE of the board.

2A seems very low as for draw, you should draw between 6 to 7A. Also, removing the solder furrle from the source connection of the output amplifier ARF transistor, notching the board and replacing with 10 gauge bare copper wire soldered to the transistor lead and to the tube input will GREATLY increase your RF delivered to the tube.

Quote:

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Originally Posted by heruursciences

If it lights you have the circuit in resonance, but for fine tuning, You may be able to adjust the ferrite tuning slug in your pre amp board in the can on the OUTPUT SIDE of the board.

2A seems very low as for draw, you should draw between 6 to 7A. Also, removing the solder furrle from the source connection of the output amplifier ARF transistor, notching the board and replacing with 10 gauge bare copper wire soldered to the transistor lead and to the tube input will GREATLY increase your RF delivered to the tube.

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So, your saying, get rid of the BNC connectors and eliminate the output pin on the FET and replace it with solid copper wire?

Get rid of the tube side BNC, keep the bard side BNC, remove the output POST from the ARF transistor board and wire a thicker copper wire directly to the output LEAD of the FET to the tube.

Here's some running video for ya'll! :D

http://www.youtube.com/watch?v=deSGne6oKPE

Wait 'till you put a ZnSe lens in front of that :D Hope you can get your drive current up. I have the single unit driver and getting about 10 amps at 30 volts. Be careful of your Scientech sensor up there.

Mike

Quote:

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Originally Posted by Hemlock Mike

Wait 'till you put a ZnSe lens in front of that :D Hope you can get your drive current up. I have the single unit driver and getting about 10 amps at 30 volts. Be careful of your Scientech sensor up there.

Mike

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Hey Mike,
Yeah, I have a big GaAs lense here. I'll try focusing tonight. Hopefully I can figure out how to get more power out of it. Should be easier now that I have it running.

The Scientech head is good for around 20W so I don't think I'll kill it from the static beam.
Thanks!
Adam

Hey Adam, Just curious, what model sensor head does your scientech meter use? I'm trying to figure out what kind of power my sensor head can handle. The meter goes up to 100W, but I think my sensor would melt at 100W :p

Quote:

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Originally Posted by GooeyGus

Hey Adam, Just curious, what model sensor head does your scientech meter use? I'm trying to figure out what kind of power my sensor head can handle. The meter goes up to 100W, but I think my sensor would melt at 100W :p

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Hey Gus,
I think it's a 36001 or something like that. The label is missing. I know it's dead on because I have tested it against other lasers and power meters, including a 3W argon at SELEM. You can also see scars in the anodizing of the housing from previous exposure to A LOT of photonic energy. my guess is that this head was wonce exposed to 100W or so.

I have the spec sheet on various heads. If you wanna give me your head model number I'll look it up for ya.
Thanks!
Adam

Mine is a 38-1UV5. It is also almost dead-on with a recently calibrated unit. The meter I use is a 364. My 365 is having some 'issues'. it doesn't let you select the range, and always thinks more than 1 range is depressed. I'm sure it's just the selection switches which need to be changed but I cant find any....

My 364 never lets me down though!

Quote:

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Originally Posted by GooeyGus

Mine is a 38-1UV5. It is also almost dead-on with a recently calibrated unit. The meter I use is a 364. My 365 is having some 'issues'. it doesn't let you select the range, and always thinks more than 1 range is depressed. I'm sure it's just the selection switches which need to be changed but I cant find any....

My 364 never lets me down though!

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The 38-1UV5 is rated for 190-360nm @ 10uW - 10W. It's basically the same thing as a 36-0001 though and will work with visible wavelengths. You can use a permanent marker on the detectors absorption plate to optimize it's visible wavelength performance.

Quote:

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Originally Posted by 300EVIL

The 38-1UV5 is rated for 190-360nm @ 10uW - 10W. It's basically the same thing as a 36-0001 though and will work with visible wavelengths. You can use a permanent marker on the detectors absorption plate to optimize it's visible wavelength performance.

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Good to know! Yeah I knew it was a UV head that was calibrated with this meter to 'work' for the visible wavelengths as well.

But it sure is a good thing I didn't have the guts to point a CO2 at it yet :eek:

Thanks for the info!!!

Hows everyone doing, Im new to this forum, but I wanted Adam (300 Evil to know I finally got in here Im Nightstick,(Lynn) Im the one with the You tube rf co2 laser... Like yours,,the one with the spinning newspaper at the beginning of the video, complements of my 13 year old Son... the one where Im melting the candle, and the one where I keep dropping the camera, also a very bad voice over:) haha anyway,I also got my laser from Chris, and I ordered two more which will have the same driver setup as yours Adam. So maybe we all can give each other some pointers I appreaciate all the info you all have put in here so far, My first co2 that you saw on youtube is a lot different than the new ones Im getting. so Im looking forward to putting them together, Great to be here Lynn

Quote:

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Originally Posted by Nightstick

Hows everyone doing, Im new to this forum, but I wanted Adam (300 Evil to know I finally got in here Im Nightstick,(Lynn) Im the one with the You tube rf co2 laser... Like yours,,the one with the spinning newspaper at the beginning of the video, complements of my 13 year old Son... the one where Im melting the candle, and the one where I keep dropping the camera, also a very bad voice over:) haha anyway,I also got my laser from Chris, and I ordered two more which will have the same driver setup as yours Adam. So maybe we all can give each other some pointers I appreaciate all the info you all have put in here so far, My first co2 that you saw on youtube is a lot different than the new ones Im getting. so Im looking forward to putting them together, Great to be here Lynn

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Hey Lynn!
Welcome to Photon Lexicon! :D
Glad to see you found me and my video. I personally think your video was just fine. Please feel free to ask any questions you'd like. Most members here, including myself, are very helpful and friendly. I look froward to communicating with you and sharing thoughts and ideas.
Thanks!
Adam

Welcome to PhotonLexicon, Lynn. Hope you like it here. We've got a few members that are experimenting with CO2 lasers now. One of the UK lads even has a portable, 10 watt CO2 laser that runs off gel-cell batteries! (Presumably not very long though.)

So the next logical question is, Adam (or Lynn): Will we be able to see one of these units at SELEM this summer? :D

Adam

Quote:

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Originally Posted by buffo

So the next logical question is, Adam (or Lynn): Will we be able to see one of these units at SELEM this summer? :D

Adam

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Well, If I haven't sold both of them by then, I'll definitely bring it. Need to put it in an enclosure with a key switch though. ;)

What should be some real fun is one of those giant Coherent laser diodes I now have. >:) Should be fun aiming that thing at stuff in the parking lot. :D Bring your IR goggles!

Evil ---

I have a couple Scientech 36-0001 heads. They are rated to 10 Watts and the beam needs to be a bit difused or they SMOKE. I've had to recoat mine after reading over 10 Watts of CO2 with these. I use a light spray of BBQ flat black high temp paint.

I'm building a ZnSe expander for mine :D

Mike

Buffo, I am able to run mine off 2x 18 volt screw gun batteries in series its really fun to be portable with these at about 7 watts very easy to fire up the leaf pile :) and I run my driver with 1x 18650 I have it all mounted in a plexi glass case trimmed out in half inch angle aluninum I will try to get some pics soon BW Lynn oh also I have a power supply for when I dont want to use the batteries

Hi Lynn;

Very cool! Interesting that you chose the clear plexiglass for the case material. I'm pretty sure that Robin (uk-laser) also used plexiglass for his portable CO2 laser. Edit: Yeah, here's a picture of his rig.

On the other hand, his is water cooled, which makes it all the more amazing that it's still portable. He can only run it for around 20 seconds though, before the water gets too hot.

Adam

where as these being convection cooled we dont need a bucket of water, but I do have a pressurized housing that has a fan built into the powersupply blowing toward the laser and cooling fins in the amp and driver, and it blows out the front keeping any smoke away from the sensitve znse lens... it works perfectly, I'm very happy with this setup, also I can easly switch over to portable battery power anytime, you know for rodent controll:D haha anyway these lasers have been nothing but fun cant wait to get two more!!!!;)

Here is a pic of my 7 watt Co2 Laser:

http://dunsoft.org/DunServer/Account...tick/Laser.jpg

With this setup I can take the 32 volt powersupply off by just unscrewing four screws, and then the powersupply fan and housing remain attached to the plexiglass housing and I just have to hook up two 18 volt ridgid screwgun batteries in series and its ready to go portable with plenty of burning power...I havent counted but Im guessing a round 20/ 10 second burns and thats a lot more than it sounds like also my li/ion batteries charge fully in only 20 minutes so if I purchase another charger for $45.00 I will be in like Flint!!!!!!:Dthis would be too cool!!!!

Hey Lynn,
Can I get a pic of your RF power supply? I'd really like to see what you have going there.

Thanks!
Adam

My portable runs on 8 x 18650 cells. They seem able to handle 12 Amps for about 10 seconds at a time. The picture doesen't show the expander which is being built. At full power, and with the 7.5" FL lens, it will put a pinhole through 1/4" of pine wood in a couple seconds.

Mike

Evil I will try to get you some pics tomorrow also Mike that build looks really nice very uncluttered I know you probably allready thought of this but a little 1x1 inch fan on the back end pushing air through to the front would be nice for cooling and also to keep smoke away from the znsn lenes not to metion the cool sound when you turn it on mohoowahhaha:eek:

The beam expander fits so tight that a little fan won't help. I hope to burn 10' from the lenses.

Mike

Quote:

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Originally Posted by Hemlock Mike

Evil ---

I have a couple Scientech 36-0001 heads. They are rated to 10 Watts and the beam needs to be a bit difused or they SMOKE. I've had to recoat mine after reading over 10 Watts of CO2 with these. I use a light spray of BBQ flat black high temp paint.

I'm building a ZnSe expander for mine :D

Mike

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Hey Mike!
Yeah, My head is only rated for 10W. Not 20W like I said previously. Good tip on the BBQ paint. I have a couple of cans at the shop and will give that a shot.

Could I also get pics of your RF PS? I want to see what everyone else has. Supposedly mine is way different. Any suggestions on getting more power out of this tube? It peaks to 4W when I turn it on and then slowly falls and levels out around 2.5W.

It seems I'm getting almost 30W of RF pre FET. Way higher than I thought it was.

That will basically ruin the calibration of your detector. The paint will have different absorbance that the standard surface...

Quote:

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Originally Posted by Laser Ben

That will basically ruin the calibration of your detector. The paint will have different absorbance that the standard surface...

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Well, I did already hit it with a permanent marker to fix the burn spots in the detector plate. However, the calibration seems to be spot on right now. I guess I have to look at the old adage.... "If it ain't broke, don't fix it" I guess I'll wait until I have a problem.
Thanks!
Adam