From smoking to crackling

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Dustin Hawkinson
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Re: From smoking to crackling

Post by Dustin Hawkinson » Fri Dec 30, 2016 4:09 pm

Checking fuses sounds like a good place to start. Also check the water flow sensor as those have a decent failure rate and will prevent voltage being applied.
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fred ungewitter
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Re: From smoking to crackling

Post by fred ungewitter » Fri Dec 30, 2016 7:19 pm

Shucks and by golly, I could not have been more incorrect about the fuse. From one tight angle, it appears to be a "common" automotive blade type fuse with 5 marked on it. From the view of a strategically placed mirror, it appears to be a 115v selector switch for power input. There goes one option for restoring use.

On the water front, or more accurately, the flow switch aspect, I figure for an easy test by attempting laser firing with no water flowing. As expected and hoped, the LCD panel displayed a flow error message. With water flowing, no error, but of course, no laser firing either. Easy test, easy answer, no solution.

The latest word from the vendor is a flip-flop, and not the footwear type. This time, I'm told to wait up twenty days for a replacement tube, purportedly shipped as part of the warranty coverage. I'm confident it will be no better power than the existing one was, that is 40-50w from the alleged 60w tube, but it's one more step in the troubleshooting process.

Does anyone have a suggestion how to test the power supply prior to the tube arrival, a method that would confirm without destroying the power supply? With the latest attempts, there is no ammeter indication, which implies no power transmitted through the tube. Is it practical to consider to connect a "dummy load" between the HV point and ground via the ammeter? If so, what resistance level should I be considering?

My electronics mathematics were never top notch, but I figure that 50 watts and 0.018 amperes should be able to be massaged through some formula to determine resistance and/or voltage? A 120 watt bulb at 120vac is about an ampere, right? Perhaps the math means 50 watts divided by 0.018 would mean 27777.78 volts or thereabouts? A quick search using The Google shows me that voltage can be expected in excess of 20kv, which means I might be in the ballpark. Knowing that one should never believe everything one reads on the internet, I chose to disregard the person whose mathematics suggested that a certain amount of current flowing through a 1.5 ohm resistor resulted in a voltage figure in the thousandths of a volt. I think what that person was overlooking was the voltage drop, not the voltage output.

Other searches on The Google also provide methods of testing to narrow down/remove aspects from consideration. It seems likely that if my power supply is good, the only way I'll know for sure is when or if a replacement tube is installed. Other methods shows on YouTube involve generating sparks external to the system, something I'm disinclined to perform.

Once again on hold awaiting the ravages of time...
fred

Redsail clone 60w 700 x 500 REAL 60w Puri tube
home upper right, chuck type rotary 15000 pulse setting
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Keith Sherwin
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Re: From smoking to crackling

Post by Keith Sherwin » Fri Dec 30, 2016 8:08 pm

:idea: Started this forum.
Lead in creation of the RDWorksLab English Manual.
Cheers, :D
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Alexis Tzoulis
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Re: From smoking to crackling

Post by Alexis Tzoulis » Fri Dec 30, 2016 8:43 pm

Use teflon..
See this video how to do it https://www.youtube.com/watch?v=YBtMBGnp5pw
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fred ungewitter
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Location: East Central FL, USA
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Laser Machine Make or Type: Redsail Clone
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Laser Bed Size: 500 x 700
Home Position: TR
RDWorks Version: 8.01.18
Accessories: Chuck style rotary, 30 ma meter, home-spun office water cooler mod, muffin fan anti-condensate blower
Windows Version: Windows 7

Re: From smoking to crackling

Post by fred ungewitter » Mon Jan 02, 2017 3:41 pm

Alexis, thanks for the reference. With a dead laser tube, the teflon will make no difference.

After seeing another forum user's woes and recommended test, I performed the same on mine. My earth ground is within reach of the HV lead when removed from the tube. I used tape to position the bare end within a few millimeters of the ground lug, providing safe distance for me.

When firing the pulse at ten percent, I get a clean continuous spark each time. I performed perhaps three tests and am reasonably satisfied that my power supply is up to the task.
fred

Redsail clone 60w 700 x 500 REAL 60w Puri tube
home upper right, chuck type rotary 15000 pulse setting
RDW 8.01.18
Win7

Emblaser A3 4w diode laser
BCN3D Sigma Dual Extruder 3d printer
LMS Mini-mill
Cube 3rd gen 3d printer, universal filament mod
Under construction: OX CNC 1000x750 router

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Keith Sherwin
Site Admin
Posts: 1593
Joined: Fri Jun 24, 2016 3:44 pm
Location: Heart of Canada
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RDWorks Version: V8.01.23
Accessories: Hot dog roller, doHICkey Power Meter, Multi-Lens, High power exhaust, Interior filter soon.
Windows Version: W7 Pro

Re: From smoking to crackling

Post by Keith Sherwin » Mon Jan 02, 2017 4:00 pm

Guess it is the tube then fred.
:idea: Started this forum.
Lead in creation of the RDWorksLab English Manual.
Cheers, :D
Keith

Dustin Hawkinson
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Re: From smoking to crackling

Post by Dustin Hawkinson » Mon Jan 02, 2017 4:43 pm

I'm glad the test worked for you Fred, and I'm sorry your tube is dead :(. I was hesitant to post instructions on how to intentionally short 25kV over an air gap, hopefully others can safely use this as well.
40W (ebay 50W blue wonder), 300mm x 500m, TL
Windows10 RDW 8.01.19
(The member formerly known as astral)
-Dustin

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fred ungewitter
Posts: 356
Joined: Tue Aug 16, 2016 2:55 pm
Location: East Central FL, USA
Country: USA
Nickname: fred
Laser Machine Make or Type: Redsail Clone
Laser Power: 60W
Laser Bed Size: 500 x 700
Home Position: TR
RDWorks Version: 8.01.18
Accessories: Chuck style rotary, 30 ma meter, home-spun office water cooler mod, muffin fan anti-condensate blower
Windows Version: Windows 7

Re: From smoking to crackling

Post by fred ungewitter » Mon Jan 02, 2017 5:20 pm

Thanks for the sentiment. I wasn't all that comfortable with making sparks, but my hobby room has no explosive vapors to ignite. I figure that the high voltage end of the tube sends current to ground at the other end of the tube, so all I was doing was shortening the path, using atmospheric gases and not body parts.

The video showing someone using a screwdriver to push the LCD button made me cringe. I don't expect these tactile button keypads to last forever and stabbing it with a pointed object isn't going to increase the lifespan!
fred

Redsail clone 60w 700 x 500 REAL 60w Puri tube
home upper right, chuck type rotary 15000 pulse setting
RDW 8.01.18
Win7

Emblaser A3 4w diode laser
BCN3D Sigma Dual Extruder 3d printer
LMS Mini-mill
Cube 3rd gen 3d printer, universal filament mod
Under construction: OX CNC 1000x750 router

Dustin Hawkinson
Posts: 158
Joined: Sat Nov 19, 2016 6:55 pm
Location: Phoenix, AZ USA

Re: From smoking to crackling

Post by Dustin Hawkinson » Mon Jan 02, 2017 9:10 pm

Yeah that was me, I used a screwdriver because I have electricians insulated screwdrivers and I didn't like the idea of touching the machine. I was careful to place the blade of the flat head on the button at an extreme angle so it was mostly flat and wouldn't cut. I still have the factory protective film on the buttons and I plan on doing something like Russ did when I eventually take it off to protect them from wear.
40W (ebay 50W blue wonder), 300mm x 500m, TL
Windows10 RDW 8.01.19
(The member formerly known as astral)
-Dustin

Michael Dunning
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Joined: Sun Nov 27, 2016 1:02 am
Location: Alabama USA

Re: From smoking to crackling

Post by Michael Dunning » Mon Jan 02, 2017 10:50 pm

Fred,

Sorry to hear about your troubles :( It seems the laser gods have decided to punish us since we last chatted, as my machine went down yesterday as well! I'll have a video about it in the "How-To" section shortly.

Anyway, I think I can answer your earlier power supply question. When I got my machine I checked all of the part numbers on the major components. Make sure to double check, but this link should have the specs for your (our) power supply:

https://www.aliexpress.com/item/general ... 63506.html

The MYJG-60 is a switchable (as you found out) 110/220V 60 watt power supply delivering up to 23ma at 35kv. So while we got shortchanged on the tube, at least the rest of the components seem up to snuff.

Let me know if you get a LO 60 watt. I wanted to get one during the Christmas sale, but they've been out of stock since November...
EBay Chinese 60W (45W actual) laser cutter, 700x500mm, (TR)
RDWorks V8.01.18 and V8.00.27
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