Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

PLUG & PLAY CO2 BURNING LASERS only $150 DELIVERED

Hemlock_Mike

Hemlock_Mike

0
Joined
Jan 7, 2007
Messages
6,309
Points
83
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

Chris ---

I first need to get my PWM back to 24 KHz. But I agree with you.

I talked to nightstick and he told me that it just quit as the SWR dropped. There's no obvious burned parts or smell.

Mike
 





N

nightstick

0
Joined
Nov 6, 2008
Messages
173
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

Chris: I was testing the SWR with my meter and when I turned the amp on the power/swr meter cross needles climbed  and droped withen 3 seconds no smoke, no heat, and the tube didnt fire, no pop, I checked the power out on the pwm its working, and a freq is showing up on my counter, but not enough power to light the tube ,Chris you probably dont have any extra amps for sale do you? thanks Lynn :)
 
H

heruursciences

0
Joined
Feb 11, 2008
Messages
730
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

Sounds like you accidentally blew up the output stage amplifier transistor or one of the LC tank capacitors. I don't have anymore amplifiers, but i do have a LOT of ARF449B RF power transistors that can replace the MRF-140's without a problem
 
N

nightstick

0
Joined
Nov 6, 2008
Messages
173
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

thanks Chris for your help, good talkin to you Ive found a good price on the power transistor$36.00 and thanks agsin for your time Lynn :)
 
Hemlock_Mike

Hemlock_Mike

0
Joined
Jan 7, 2007
Messages
6,309
Points
83
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

Lynn -- guess I'm the lucky one here -- I think I have my capacitor heating problem under control :) I don't think these were designed to run at LOW power. Only at near rated power. The low duty cycle pulses may cause the loading on that circuit. I'd sure like a schematic !!! hint hint ;D

Mike
 
M

Meduza

0
Joined
Jun 2, 2008
Messages
8
Points
3
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

Is the status in the first post still correct (that there is two complete lasers left for 350+shipping) ?

If so, i am a little intrested...

// Erik aka Meduza
 
N

nightstick

0
Joined
Nov 6, 2008
Messages
173
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

yes you are the lucky one Im gonna try to fix mine and leave it alone :)
 
Hemlock_Mike

Hemlock_Mike

0
Joined
Jan 7, 2007
Messages
6,309
Points
83
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

Lynn ---

You are miles ahead because of your Ham radio knowledge :) I don't know if a 50 ohm dummy load would help but at least you wouldn't have to watch out for the beam. I think your driver unit is a little different than mine and with a single output transistor, a short or open coax is the likely cause for failure.
Check your BNC's !!

Mike
 
N

nightstick

0
Joined
Nov 6, 2008
Messages
173
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

Thanks Mike I will order a transistor and get to it If I have any questions Im callin :D oh and I do have a dummy load thats a good idea I do have a very weak lase just enough to light paper in about 7 seconds ;)
 
N

nightstick

0
Joined
Nov 6, 2008
Messages
173
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

To put everyones's mind at ease it is confermed it was a short in my coax jumper it didnt take but three seconds and it blew my mrf422, anyway we live and learn if everything was perfect we wouldnt have anything to look forward to,,, like a new transistor coming in the mail lol :-? ps thanks Chris for your help and you too Mike :D :D
 
drlava

drlava

0
Joined
Mar 7, 2007
Messages
1,152
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

I have to admit, these are pretty cool!
Mike when you get your unit finished, I'd like to see a video of you firing it at an operating CRT monitor :)
 
N

nightstick

0
Joined
Nov 6, 2008
Messages
173
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

I wanna see that,, I shot a peice of bologna the sound effects were cracklin and poppin!!! and boy did it smell good :D
 
Hemlock_Mike

Hemlock_Mike

0
Joined
Jan 7, 2007
Messages
6,309
Points
83
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

But wait ---  This just in !!
Chris is a poet of scientific leaning  ;D    He responded to my driver fix using some ferrite beads in a most insiteful way.  I hope you appreciate his fine words.   "Ode to a Powdered Iron Bead"

"How great thou art thy mighty yet humble ferrite bead!  Ye deliver us from unwanted inductive coupling and filter the voltage. How great is it that ye deliver us from thy terrible fate of a blown capacitor and smoked components forever and ever. All hail the ferrite! "

Read and learn crickets!!!!!!    ;D

Mike

Oh DrLava --- You see, I have some pesky tree rats that get too close here and . . . .. uh- nevermind ::)
 
drlava

drlava

0
Joined
Mar 7, 2007
Messages
1,152
Points
0
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

Hemlock Mike said:
Read and learn crickets!!!!!!    ;D
Click to expand...

Only 1 suggestion:

"and filter the voltage" -> "and filter the current"

because an inductor resists changes in current not Voltage.
 
Hemlock_Mike

Hemlock_Mike

0
Joined
Jan 7, 2007
Messages
6,309
Points
83
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

OK I also added 47 mFd of capacitor in there too!!!   But that's not poetic  :D
Adding inductance in a high frequency noise environment can reduce voltage spikes which may have been part of the problem.

Mike
 
S

spikec

0
Joined
Oct 20, 2008
Messages
38
Points
6
Re: OUTRIGHT BUY! 15W RF EXCITED CO2 BURNING LASER

OK, my 28vdc PS was DOA, so we decided to hook up two 12V car batteries in series to get this thing fired up. We had the laser hooked to Batt 1 as the load and Batt 2 connected to Batt 1 via jumper cables. Right after we completed the circuit, one of the guys knocks off the the neg. cable from Batt 2, and the laser gets hit with only 12V from Batt 1. I hear a pop and a burning smell from the laser PS board, and upon inspection see that the 7815CT volt reg. is cracked. No other obvious damage.

The VR is a cheap part and easily replaceable, but I'm wondering if anyone can venture a guess as to why it got trashed and what other components might be damaged too.

Thanks,

Spike
 
You must log in or register to reply here.




Top