[buddydog]

Ok so what makes me qualified to "instruct" troubleshooting one of these when I have only been at it for a month? We'll over 50 years in the troubleshooting business both electronic and engine. I'll be concentrating on simple tests you can do at home with a minimum of equipment or just observation. This is also a synthesis of reading I have done on here and elsewhere by several experienced persons but the information is not shown completely in one place. This will NOT be a "how to fix software" problem thread at least on my part. Maybe some folks knowledgeable in those areas will add to this and help there. These posts will address control of the power supply at the low voltage level and also the high voltage for firing the tube. My observations will be based on my own machine which is the upgraded 40 watt (actual probably 30 watt) unit with USB, LaserDRW software, LED power indicator panel and the all-in-one power supply. Other machines are similar but use the "knob" rheostat power control and the milli ammeter for power indication.

These machines at least at the entry level are stupid simple and with a little care and knowledge you can understand them. The tube has a gas in it that is excited by a high voltage applied to a terminal at each end of the tube. I don't see how it would matter but they all seem to have the high voltage plus or positive applied to the end farthest from the output tube end and ground is attached to the (beam) output end. You could fire the beam by just turning the high voltage on and off, beam on and beam off (This is what the test switch does. It just turns the beam on and keeps it on until you let go of it). Not very useful except for starting fires and alignment but if you do not have any laser output you will mostly be concerned with the operation at this basic level since you can't laser anything without the "beam"!


.Measuring high voltage with a proper high voltage probe:

The first picture is my what is an apparently "good" tube firing at 40% power. Same with the last picture. Now this one is working fine and was burning a hole in plywood while I was taking the picture. Yours could look like this and not be putting any power out if there is something wrong internally with the mirrors inside the tube or some other problem, but we do have high voltage and it is exciting the gas that is inside the tube. You have to start someplace.

Inside the electronics bay is either an all-in-one power supply or maybe a bunch of different supplies for each voltage but basically you will have a 5 volt DC, a 12 vdc or 24 vdc supply. You also will have an approximately 15-20,000 volt power supply. This entry tonight will be about the high voltage supply. The purpose of this supply is to excite or fire the gasses inside the CO2 tube. This generates the invisible beam that we use for lasering. This light inside the tube is NOT the laser beam. Apparently the supply has to first fire the laser at about a 10-20% higher voltage and then it drops to the running voltage until it turns off. In middle "meter" picture I am holding the camera while also holding the probe on the end of the wire that's exposed by the connection to the tube. No voltage is showing because I can't fire, hold the probe, and hold the meter all at the same time. When I did fire it at 40% power the meter "kicked" up and then fell back to about 10,000 volts measured. The meter is a Heathkit IM-5210 test probe. The ground wire side of the meter is connected to the ground post on the rear of the cabinet.


A word about safety: It's a difficult thing to explain all the ins and outs of high voltage but it can travel along even non conductors and over dirty insulators so be very respectful. I cleaned the body and fins of my meter with a clean dry rag before running my test. The bird-on-the-wire shows us that it's perfectly safe to touch a hot wire if there is no path back to the origin of the voltage. In this case that means back to ground! Unfortunately for 20,000 volts that can be a short distance in air, through the soles of your shoes, concrete, wood floor, the laser metal case, just about anything except a couple inches of clean dry plastic or glass. SOOO. Don't get any part of your body between the high voltage in these machines and ground!

Let's get right to it in this first installment with the scariest and most dangerous part! How do you avoid grounding yourself and making a complete circuit through your body and test the high voltage? First remove all loose clothing off of yourself, remove rings, ear rings, chains or other garbage bling that can dangle or conduct and get them away from the work/test area. Now step onto a clean dry 5 gallon plastic bucket that has been inverted so you can stand on the bottom of it (If your fat get someone else to do this part). Make sure of your footing and don't allow any movement while you are doing any of this to get any part of you closer than a foot to any ground including the laser cabinet, the wall behind you etc. You will insure that a helper pushes any test buttons etc at your verbal direction so you holding the test instrument have only one job to do and you don't have to move while taking the measurement. In the middle picture I am making the high voltage measurement with a HIGH VOLTAGE METER! Not some standard voltmeter which besides electrocuting you destroys itself in the spectacular arc!. Are you completely away from anything except the DRY,CLEAN, plastic bucket your standing on? OK your probably safe and this will be just another day you can tell your grandkids about.: While touching the exposed wire on the high voltage end of the tube with the test probe, have your assistant fire the test button and you should read 10-15,000 volts. If you do we can have a 99% (never believe 100% with troubleshooting) confidence the power supply is operating correctly and incidentally the ."test" button and it's control circuitry is fine. If you don't see any voltage or it's really low during this test examine the tube and so forth for carbon tracks, check where the wire comes into the tube bay from the electronics compartment. I said "look" not touch. Shut everything off and with a shorting wire bleed any remaining voltage from the tube high voltage connection to ground. Wait a minute and do it again. If the high voltage was close to correct but the tube didn't light up inside it's a fair bet the tube is dead and requires replacement. If you have no voltage use your eyes to make sure there are no shorts (touching or even close) to ground along the high voltage wire.

Ok you don't have the fancy meter? Well I would suggest getting one but I have come up with another way to "barnyard" test for high voltage: I call it the "Lucius Gale
test": Find a Styrofoam packing peanut. Get a dry piece of cotton thread a foot or so long. Tie one end of the thread to the packing peanut and leave about an 8 inch tail of thread to hold onto. While firing the laser with the test button, bring the packing peanut within about 2 " from the insulated high voltage lead and a little lower than the lead so it can swing in a arc to the wire. At 40% power mine causes the packing peanut to swing solidly over and stick to the wire. It only barely deflects it at 10% power. Not really a very conclusive test but I think if the test is successful you have enough high voltage to fire the tube and your supply is at least "adequate". This does not say anything about power level but just a rough test with things on hand. No deflection would mean no high voltage and barring a shorted wire would point you in the direction of the power supply output or the control circuitry.

In my next installment we will examine the power supply control system. Don't order anything yet!

Does this topic seem useful to anyone? To basic? To complicated?? Incorrect in some way? Also one of the threads I saw mentioned a spark gap test. I don't really like that because it allows the voltage to vary up and down as the arc forms all over the place possibly causing an arc to start a carbon track internal inside the power supply high voltage transformer possibly damaging it immediately or in the future, but maybe not. If anyone has actually performed that test maybe you could describe it in detail. I notice the manufacturers recommend a test with a resistive load and if we had something like that it would also be a very good test.

[Holychachi]

I enjoyed reading your post, very informative.
I recently had the laser tube go out on my 50w machine, at least I think that's what happened. I have a cheapo chinese machine I bought used on craigslist about a year ago. The machine has performed admirably this whole time, until yesterday. I was in the middle of cutting and suddenly noticed, 'hey there's no beam cutting the plywood anymore. Never heard any pop crackle boom pow or anything that would indicate a problem. The only thing i did notice was a slight odor. I wouldnt say it had that 'I definitely just fried something electrical'smell, but it was a different smell than what I usually smell with my machine. I visually inspected the tube, no cracks, that I can see. Up to this point I hate to admit that I gave been running my machine with little knowledge of how the electronics inside do their job.

So now I'm trying to learn up on it all so I can run my machine more efficiently and have a real understanding of what's going on. I took a peak at the psu and from what my novice eyes xan tell everything looked and smelled fine. Also when I push the test fire button, the light on the panel lights up, I just don't get anything from the tube. I ordered a new tube last night and am hoping to just replace and everything works again.

All this leads me to a few questions. All I know about my current setup is that it's a 50w tube, or at least that's what I was told. I know nothing about my power supply. I was wondering if there is anyway to look at your power supply and be able to tell what output it is or anything about it. I just want to make sure I've got the correct, or best psu/tube combo. I was cutting at 80% power for about 30 minutes when my tube went out. I have a feeling I was sending too much current to the tube for too long and killed it. I have decided I am going to add a 50mA ammeter to my machine so I can monitor that on my new tube. Another question I have is do I need to figure out what voltage my psu is producing, is that something that could be too high? Or do I assume it is in the acceptable range since my last tube operated well? I hear there is a potentiometer to adjust the current, is there anyway to adjust the voltage?

Thanks,
Charlie

[buddydog]

Don't take this wrong Charlie but you already didn't take my advice to "don't order anything yet". The way you described that there is a smell I doubt it is your tube and when you get the new one just resell it as they apparently don't store very good or long. To bad since I would like to have a spare on hand myself. Anyway. first thing to do is see if you have output from the tube and don't have a mirror that "moved". BE VERY CAREFUL while running this test. A mirror out of alignment can send the beam anywhere!! Just wear some cheap plastic safety glasses and keep the test short.Hold a piece of paper directly in front of the output of the tube before the first mirror and hit the test button. Did it burn a hole in the paper? If so you have a mirror/lens/alignment problem. If not look at the side of the tube while hitting the test button. Any strange light inside the tube while firing? If yes then maybe a bad tube. If no the proceed to the peanut test as described in my post above. Also with everything off clean all the high voltage connections from dust, spiders, etc. If you have no high voltage you can look for dirt, bad connections etc BUT the fact you smelled something would most likely be a resister that has fried. I don't know about the 50watt machine but the 40 watt has a big green resister in the ground return and I would suspect that. Finally since the test light is working and if you have no high voltage and barring any visible problems then a new power supply is probably the next good guess since I gather you are not into electronics and besides I know of no schematics or parts available for these units. I am particularly interested in the results of the "peanut" test. Good luck!

I enjoyed reading your post, very informative.
I recently had the laser tube go out on my 50w machine, at least I think that's what happened. I have a cheapo chinese machine I bought used on craigslist about a year ago. The machine has performed admirably this whole time, until yesterday. I was in the middle of cutting and suddenly noticed, 'hey there's no beam cutting the plywood anymore. Never heard any pop crackle boom pow or anything that would indicate a problem. The only thing i did notice was a slight odor. I wouldnt say it had that 'I definitely just fried something electrical'smell, but it was a different smell than what I usually smell with my machine. I visually inspected the tube, no cracks, that I can see. Up to this point I hate to admit that I gave been running my machine with little knowledge of how the electronics inside do their job.

So now I'm trying to learn up on it all so I can run my machine more efficiently and have a real understanding of what's going on. I took a peak at the psu and from what my novice eyes xan tell everything looked and smelled fine. Also when I push the test fire button, the light on the panel lights up, I just don't get anything from the tube. I ordered a new tube last night and am hoping to just replace and everything works again.

All this leads me to a few questions. All I know about my current setup is that it's a 50w tube, or at least that's what I was told. I know nothing about my power supply. I was wondering if there is anyway to look at your power supply and be able to tell what output it is or anything about it. I just want to make sure I've got the correct, or best psu/tube combo. I was cutting at 80% power for about 30 minutes when my tube went out. I have a feeling I was sending too much current to the tube for too long and killed it. I have decided I am going to add a 50mA ammeter to my machine so I can monitor that on my new tube. Another question I have is do I need to figure out what voltage my psu is producing, is that something that could be too high? Or do I assume it is in the acceptable range since my last tube operated well? I hear there is a potentiometer to adjust the current, is there anyway to adjust the voltage?

Thanks,
Charlie

[Holychachi]

I took some pictures to go along with this post. I first tried putting the paper in front of the end of the tube and as expected, nothing happened. Next I tried pressing fire and looking in the tube, but I saw no light, no sound, nothing. I took a flashlight and inspected the tube and noticed what looks like sediment in the inner cylinder of the tube, just in the one area shown in the pics. I tried to get a decent picture of it. I also took some photos of the guts of my machine. I'm wondering which box is actually the power supply, and what is the other box?

Also you'll notice my contacts(?) On my laser tube have tubing over them. I put the tubing over them and filled with silicone to prevent arcing. I did this about 10 months ago when I first got the machine. I don't know if I can do the peanut test with the terminal (?) Covered the way it is? In one of the photos I took a closeup shot of part of the circuit board. There is an led with an 'L' marked by it. When I press the test fire button, this led comes on. I don't know if I mentioned this before but now whenever I press the fire button or activate the laser, since it's not working, I hear no sound. When the laser was working good, you could always tell when the laser fired, because you could hear the sizzle or crackle of the laser.

So, I know I need to do the peanut test next, but don't know if I can with that silicone on there. Also could that sediment have made my tube go out? Any more advice you can give, I'm all wars. I really appreciate your help.

Charlie

Don't take this wrong Charlie but you already didn't take my advice to "don't order anything yet". The way you described that there is a smell I doubt it is your tube and when you get the new one just resell it as they apparently don't store very good or long. To bad since I would like to have a spare on hand myself. Anyway. first thing to do is see if you have output from the tube and don't have a mirror that "moved". BE VERY CAREFUL while running this test. A mirror out of alignment can send the beam anywhere!! Just wear some cheap plastic safety glasses and keep the test short.Hold a piece of paper directly in front of the output of the tube before the first mirror and hit the test button. Did it burn a hole in the paper? If so you have a mirror/lens/alignment problem. If not look at the side of the tube while hitting the test button. Any strange light inside the tube while firing? If yes then maybe a bad tube. If no the proceed to the peanut test as described in my post above. Also with everything off clean all the high voltage connections from dust, spiders, etc. If you have no high voltage you can look for dirt, bad connections etc BUT the fact you smelled something would most likely be a resister that has fried. I don't know about the 50watt machine but the 40 watt has a big green resister in the ground return and I would suspect that. Finally since the test light is working and if you have no high voltage and barring any visible problems then a new power supply is probably the next good guess since I gather you are not into electronics and besides I know of no schematics or parts available for these units. I am particularly interested in the results of the "peanut" test. Good luck!

[buddydog]

Fine business Charlie. First I am envious of your machine being the bigger 50 watt! Also I reread my post from yesterday and I might have given the impression that seeing the discharge in the tube meant it was bad and that is not true. I just meant if the discharge inside the tube was there it meant you have high voltage. With either bad control (software board or test switch), dead tube, or no high voltage, you would have the situation you see in yours.

Now as to the "Lucius Gale peanut test": Nothing is removed, changed, exposed etc. Just dangle the peanut "near" the red lead (remember the peanut is tied on the end of a long dry cotton thread so no body parts are anywhere near the high voltage and you are standing on an inverted plastic bucket with nothing near a ground and a helper is pressing the test button) while pressing the test switch and it should jump right over and stick to it. This is anywhere along the red lead from where it comes out of the power supply to where it attaches to the tube. High school (the old high school where you actually learned something) physics class. If it doesn't do that you have two likely possibility's with the first being something wrong with the wire (grounded, broken, connections all pretty unlikely as high voltage jumps through just about anything) OR, the likely cause of "no high voltage with the red test light lit" Ta da: bad power supply. Relatively cheap on ebay. I would encourage fixing the supply but since there is no schematics, parts etc. and they are cheap just replace it after the simple tests I described. My posts are only to help make an informed decision instead of a "dart board" one. Your new tube could fix the problem but you didn't have enough info to make that decision and it may have cost time and money and frustration leading to " crap Chinese machine" comments you read so often on these forums.

I want to add another thing to this post. It's something I haven't tried so I don't know for sure what the proper indication would be but I suspect there should be "no" attraction of the peanut to the ground black wire (attached to the output end of the tube on my machine). If I remember right that black wire goes to that big green resister and if it "opened" (fried for the layman) then the voltage should go "high" on the ground lead and it would attract the peanut which "should" indicate a bad ground connection. I think that resistor is a meter shunt to measure current but I'm not positive. All of this paragraph is suspect as I have not actually tried this and depending on the value of that resister some high voltage could be backed up behind it causing the black lead to attract the peanut even in a working machine. Anyway I could check that on a running machine if you get this far.

Lastly in your original post you said something about "adding a meter". I would strongly recommend you don't. Just make sure everything is factory and don't mess around with the high voltage end of things. If you want to do anything buy one of the "high voltage" meters like I described in my first post and get a bench mark reading on your machine when you get it working and you will have an accurate test system to use the next time this happens. Please please let us know how this turns out and also I am happy to help more as you go along.

I took some pictures to go along with this post. I first tried putting the paper in front of the end of the tube and as expected, nothing happened. Next I tried pressing fire and looking in the tube, but I saw no light, no sound, nothing. I took a flashlight and inspected the tube and noticed what looks like sediment in the inner cylinder of the tube, just in the one area shown in the pics. I tried to get a decent picture of it. I also took some photos of the guts of my machine. I'm wondering which box is actually the power supply, and what is the other box?

Also you'll notice my contacts(?) On my laser tube have tubing over them. I put the tubing over them and filled with silicone to prevent arcing. I did this about 10 months ago when I first got the machine. I don't know if I can do the peanut test with the terminal (?) Covered the way it is? In one of the photos I took a closeup shot of part of the circuit board. There is an led with an 'L' marked by it. When I press the test fire button, this led comes on. I don't know if I mentioned this before but now whenever I press the fire button or activate the laser, since it's not working, I hear no sound. When the laser was working good, you could always tell when the laser fired, because you could hear the sizzle or crackle of the laser.

So, I know I need to do the peanut test next, but don't know if I can with that silicone on there. Also could that sediment have made my tube go out? Any more advice you can give, I'm all wars. I really appreciate your help.

Charlie

[buddydog]

Just went back and read your second post. The blue power supply is the "all in one low voltage-high voltage power supply". I don't know what the other one is? Maybe stepper controllers??. Do those wires from it go to the steppers of your bigger machine? Mine are controlled from the electronics board directly if I remember right. The blue box is the suspect one. Again it's been a while but "L" terminal I think must represent "light control" and I think K+ and K- go to interlock switches? It's been a while since I have looked inside my machine. You know my machine does not have any interlocks. Does yours??? I had not thought of that. If you do I could describe how to test those and those could be your problem. That hinges on if the test LED comes on with the interlocks "off" normally. Hmmmm? I also discount "interlock theory" since you smelled something and I would not suspect a switch of "smelling". Normally they just quit closing ("closing" means "on") if bad.

I took some pictures to go along with this post. I first tried putting the paper in front of the end of the tube and as expected, nothing happened. Next I tried pressing fire and looking in the tube, but I saw no light, no sound, nothing. I took a flashlight and inspected the tube and noticed what looks like sediment in the inner cylinder of the tube, just in the one area shown in the pics. I tried to get a decent picture of it. I also took some photos of the guts of my machine. I'm wondering which box is actually the power supply, and what is the other box?

Also you'll notice my contacts(?) On my laser tube have tubing over them. I put the tubing over them and filled with silicone to prevent arcing. I did this about 10 months ago when I first got the machine. I don't know if I can do the peanut test with the terminal (?) Covered the way it is? In one of the photos I took a closeup shot of part of the circuit board. There is an led with an 'L' marked by it. When I press the test fire button, this led comes on. I don't know if I mentioned this before but now whenever I press the fire button or activate the laser, since it's not working, I hear no sound. When the laser was working good, you could always tell when the laser fired, because you could hear the sizzle or crackle of the laser.

So, I know I need to do the peanut test next, but don't know if I can with that silicone on there. Also could that sediment have made my tube go out? Any more advice you can give, I'm all wars. I really appreciate your help.

Charlie

[Holychachi]

Unfortunately I won't be able to work on troubleshooting my machine tonight. We have some strong storms brewing and I don't want like to have my machine powered on or even plugged in when it's storming. I'm going to try and work on it tomorrow and I'll let you know the results.

Charlie

Just went back and read your second post. The blue power supply is the "all in one low voltage-high voltage power supply". I don't know what the other one is? Maybe stepper controllers??. Do those wires from it go to the steppers of your bigger machine? Mine are controlled from the electronics board directly if I remember right. The blue box is the suspect one. Again it's been a while but "L" terminal I think must represent "light control" and I think K+ and K- go to interlock switches? It's been a while since I have looked inside my machine. You know my machine does not have any interlocks. Does yours??? I had not thought of that. If you do I could describe how to test those and those could be your problem. That hinges on if the test LED comes on with the interlocks "off" normally. Hmmmm? I also discount "interlock theory" since you smelled something and I would not suspect a switch of "smelling". Normally they just quit closing ("closing" means "on") if bad.

[Holychachi]

So, I just did the peanut test. Instead of standing on a inverted 5gal bucket, I just attached the Styrofoam to a string and hung it from the ceiling about an inch from the red wire near the end of the tube. I hit test fire many times and never noticed and considerable movement, other than the wind from outside occasionally blowing it around. Im assuming if there was high voltage in the wire then the peanut would have made a noticeable movement...? So, where I stand now, no movement from the peanut test, and no light in the tube when hitting test fire. I do still get a green power light on my power supply control board when I turn the machine on, and the test led comes on the board as well when I hit test fire. So I guess the board is still getting power, just not putting out on the high voltage side?

So my next question, how can I safely remove my psu? Id like to do a good visual inspection and do continuity tests with my multimeter to see if I can pin down the problem before I just go and order a new power supply. I've already ordered a new tube, probably 30,000ft over the Pacific Ocean right now... :/ So before I go spending anymore money, I want to do a better job nailing down the problem.
Also figured out my power supply is model MYJG-40W, if that helps at all.

I may be jumping the gun here, but im starting to suspect the flyback transformer may be the culprit.

[Holychachi]

You still around buddydog?

Just went back and read your second post. The blue power supply is the "all in one low voltage-high voltage power supply". I don't know what the other one is? Maybe stepper controllers??. Do those wires from it go to the steppers of your bigger machine? Mine are controlled from the electronics board directly if I remember right. The blue box is the suspect one. Again it's been a while but "L" terminal I think must represent "light control" and I think K+ and K- go to interlock switches? It's been a while since I have looked inside my machine. You know my machine does not have any interlocks. Does yours??? I had not thought of that. If you do I could describe how to test those and those could be your problem. That hinges on if the test LED comes on with the interlocks "off" normally. Hmmmm? I also discount "interlock theory" since you smelled something and I would not suspect a switch of "smelling". Normally they just quit closing ("closing" means "on") if bad.

[Holychachi]

I got the new tube today and installed it. As expected, nothing happened when I tried to test fire it. I decided to pull out the psu and open it up to see if anything looked off. Well the thing that stood out was the flyback transformer. It is blackened or covered with soot, you might say, on the bottom half. Also after further inspection I noticed a small crack about 3/8" long on top of it. I have attached pics of it. Is there a way to test it with a plain 'ol multimeter? From the pictures do you suspect it could be the problem?

Charlie

[Downunder35m]

The black stuff can be quite normal due to the high voltage attracting fine dust and the heat produced in general.
However, a flyback should never have cracks, this is usually a sign of burnout.
If you still have some old TV repair shops around you can ask them for a quick check or solder it out and use the youtube videos for checking the flayback.
There is also a chance that the driver itself, (the mosfets or transistor on it) has failed once the flyback was done and dusted.

[Holychachi]

That all makes perfect sense. We used to have a handful of repair shops around here, but the last one went out of business a few years back. If I order a new flyback transformer it will take about two to three weeks to get here. ..from China, of course. The new flyback would be about $60 after you add in shipping. think I may be better off just ordering a new 50w power supply to go with the new 50w tube I just got. I just want to make sure I find one that has similar, if not the same, connections that my current psu. Thoughts?

Charlie

The black stuff can be quite normal due to the high voltage attracting fine dust and the heat produced in general.
However, a flyback should never have cracks, this is usually a sign of burnout.
If you still have some old TV repair shops around you can ask them for a quick check or solder it out and use the youtube videos for checking the flayback.
There is also a chance that the driver itself, (the mosfets or transistor on it) has failed once the flyback was done and dusted.

[Downunder35m]

If you have no easy means to get it all checked and fixed than a new power supply is certainly the best option, especially if you upgrade to something with better safety and protection.

[buddydog]

Hi again Charlie. I've been busy the last couple of days cleaning out my hanger since I sold my airplane and I found a renter right away so had to clean out all my hording! When I finish the cub and reclaim my hanger I will not use the hanger as a storage unit ever again. What a mess. Anyway I was not checking my email for a couple of days but I'm back.

Yes I was pretty sure you would have to buy a new supply. I think they are about 125-150 on ebay. BUT first does your machine have that big green resistor in the ground lead? Also you never said if your machine has any interlocks? Might as well figure out for sure before you spend more money.

That all makes perfect sense. We used to have a handful of repair shops around here, but the last one went out of business a few years back. If I order a new flyback transformer it will take about two to three weeks to get here. ..from China, of course. The new flyback would be about $60 after you add in shipping. think I may be better off just ordering a new 50w power supply to go with the new 50w tube I just got. I just want to make sure I find one that has similar, if not the same, connections that my current psu. Thoughts?

Charlie

[Holychachi]

No green resistor and no interlocks. My machine is pretty sparse. I did notice that rather large crack in the top of my flyback transformer and just worry about ordering that part then finding out there's more to the problem. At this point my machine has been down almost two weeks. That's two weeks without getting any work done. Money down the drain. So I think I'd be better off just ordering the whole psu. I noticed that the psu that was in there appears to be a 40w. Model MYJG40W. The guy I bought the machine from said it was a 50w machine, he had just put a new 50w tube in it. The tube he put in it was about 800mm long and 50mm in diameter. I'm wondering if it was actually a 40w tube. It had no labels or stickers on it. If it was a 50w tube on a 40w rated psu, could that have caused the psu to go out?

We'll the tube I bought is a 50w. So I'm wondering if I can just buy that same cheap psu I had or if I need to find specifically a 50w psu. From looking at the capabilities of my tube and the capabilities of that same psu, it seems that that same one would work just fine. The voltages and currents of my new tube all lie within the specs of the same psu. Thoughts?

Charlie

Hi again Charlie. I've been busy the last couple of days cleaning out my hanger since I sold my airplane and I found a renter right away so had to clean out all my hording! When I finish the cub and reclaim my hanger I will not use the hanger as a storage unit ever again. What a mess. Anyway I was not checking my email for a couple of days but I'm back.

Yes I was pretty sure you would have to buy a new supply. I think they are about 125-150 on ebay. BUT first does your machine have that big green resistor in the ground lead? Also you never said if your machine has any interlocks? Might as well figure out for sure before you spend more money.

[buddydog]

Yep with those last questions answered, crack or no crack I would suggest ordering the whole supply and be done with it. Problems in a high voltage supply can feed back or back up excessive voltage that takes out other components sometimes breaking down later. Repeaters I took care of on mountain sites used to get hit by lightning and I would go up and replace the antenna and maybe the final amplifier and get it working but then sometimes within hours another component would give out and back up the mountain again. then maybe it would behave for a week or so then something else would go. Generally replacing the whole radio was the best policy if it didn't settle down in a couple of weeks.

I can't say for sure about the ratings of the supply you have. I am sure it's the same one I have in my 40watt set. I usually don't try and cut plywood in one pass and run below 65% normally and make more passes and put bag ice in the water to keep the efficiency up. If you need to get going fast just order the same one. I think the last I checked they were $90 or something like that. Now at least where the high voltage is concerned you could order a bigger supply and run it de-rated. Mine varies the voltage to limit the current so your is the same. Since you have a bigger size machine you maybe able to run a 60 watt tube with a bigger supply and do your work faster?? I know that is what I would do if the tube would fit. Still envious of the work area on your machine.

No green resistor and no interlocks. My machine is pretty sparse. I did notice that rather large crack in the top of my flyback transformer and just worry about ordering that part then finding out there's more to the problem. At this point my machine has been down almost two weeks. That's two weeks without getting any work done. Money down the drain. So I think I'd be better off just ordering the whole psu. I noticed that the psu that was in there appears to be a 40w. Model MYJG40W. The guy I bought the machine from said it was a 50w machine, he had just put a new 50w tube in it. The tube he put in it was about 800mm long and 50mm in diameter. I'm wondering if it was actually a 40w tube. It had no labels or stickers on it. If it was a 50w tube on a 40w rated psu, could that have caused the psu to go out?

We'll the tube I bought is a 50w. So I'm wondering if I can just buy that same cheap psu I had or if I need to find specifically a 50w psu. From looking at the capabilities of my tube and the capabilities of that same psu, it seems that that same one would work just fine. The voltages and currents of my new tube all lie within the specs of the same psu. Thoughts?

Charlie

[Holychachi]

When my laser went down I basically panicked. I have a trade show this weekend and I was building up my inventory. In my haste I ordered the 50w tube, which as you know didn't fix the problem. I would love to go ahead and upgrade to 60 watts but after just ordering the new 50w tube, that would be hard to sell to the wife. I figure I'll run this 50w until it burns out, then promptly upgrade to a 60w. I want to upgrade my controller as well, all in due time. I guess as long as it's still going, and doing what I need it to do, though not as well as a 60w woukd, I'll keep running with what I got. Heck, who knows, maybe if my stuff sells well enough I will be able to just buy a second machine, 60w or maybe 80w. Hey, a man can dream, right?

Yep with those last questions answered, crack or no crack I would suggest ordering the whole supply and be done with it. Problems in a high voltage supply can feed back or back up excessive voltage that takes out other components sometimes breaking down later. Repeaters I took care of on mountain sites used to get hit by lightning and I would go up and replace the antenna and maybe the final amplifier and get it working but then sometimes within hours another component would give out and back up the mountain again. then maybe it would behave for a week or so then something else would go. Generally replacing the whole radio was the best policy if it didn't settle down in a couple of weeks.

I can't say for sure about the ratings of the supply you have. I am sure it's the same one I have in my 40watt set. I usually don't try and cut plywood in one pass and run below 65% normally and make more passes and put bag ice in the water to keep the efficiency up. If you need to get going fast just order the same one. I think the last I checked they were $90 or something like that. Now at least where the high voltage is concerned you could order a bigger supply and run it de-rated. Mine varies the voltage to limit the current so your is the same. Since you have a bigger size machine you maybe able to run a 60 watt tube with a bigger supply and do your work faster?? I know that is what I would do if the tube would fit. Still envious of the work area on your machine.