Laser weirdness

[Matthew Gates]

So I clicked the "draw frame" in Newly Draw instead of the "move
frame" to align my work, and now the guide laser is just flashing on
and off and the laser is not doing anything useful. It just moved to
the centre of the work area (didn't hit the edge or anything like
that), stopped moving and commenced this flashing.

Even with power cycling, and reboot of laptop, same thing, and newly
draw doesn't seem to be able to pass it instructions either.

Anyone know how to reset it?

Mouse

[Dominic Morrow]

Nope. What do you mean by the guide laser is flashing? Do you mean the LED laser diode LED? I assume you've tried shutting everything down? What happens when you reset XY?

Please just put a do not use sign on it please. 

Dominic

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[Matthew Gates]

Yes, the LED laser diode which shows approx where the laser will cut.

I did try shutting it down - waited for cooling, and then powered off
completely including at the wall, waited 30 seconds, and turned back
on. No change. Newly draw also refuses to communicate with it.

I also tried hitting the emergency stop and then un-set the button,
but no change. It's very frustrating.

Mouse

[Dominic Morrow]

Sounds like it might be a power supply problem. Best to leave it b. Could you put a do not use sign on it. 

Thanks

Dominic

[Matthew Gates]

Yes, sign is up. Looking in forums and manuals in case there's a
simple solution. I tried phoning HPC too, but the number on the laser
doesn't seem to work. Is their support worth seeking?

[Jimena]

Hi, 

I was taken some time to write about the Laser Cutter. I was working with it on Wednesday. I first did a try to cut an small piece of my work and it did it well. So I tried with the entire piece of work and it only did the engrave part and the cutting part was done but the laser actually did not cut. I tried again with an ssmall piece and didn't work. I changed the speed but it didn't change. 

I hope we can find out what the problem is. 

Thank you so much!

Jimena

[David Hayward]

I took a quick look at this with Mouse yesterday evening. The aiming laser blinks at a regular rate, and in the control section there's an LED on each of the PCBs that blinks in time with it, so it looks like some kind of diagnostic. The light, compressor, and water pump all still work, and the connections to the boards all seem to be intact.

[Dominic Morrow]

I think it's a power supply problem. 

Sent from my iPhone

[Dominic Morrow]

I had a good look at the laser on Friday.  As David H said there is a flashing light on the control board and the power supply. 

I've a number of options at this point. Swapping out the power supply would seem like a good idea only they are about £75 a pop. Ill have a look in my blue laser to see if the power supplies are the same and if they are ill swap them to see if that's the fault. 

Other options might be to ask Ben if he'd let me try the power supply in his machine. 

Of course it might be the control board at fault. Or it might be both. I'm not especially keen to contact HPC as they'll most likely want to look and fiddle before offering a suggestion and I can't afford the call out, labour and parts cost from them (likely to be 300 to 400% more than buying the part and fitting it myself).

I'd welcome any suggestions here if you have them.

Dominic 

Sent from my iPhone

On 17 May 2013, at 11:37, David Hayward <nach...@gmail.com> wrote:

[David Clarke]

Is this the HV power supply for the laser tube itself?

A flashing light on the power supply could indicate that it is sensing an
overload or other fault condition. Can the PSU be disconnected completely
to determine whether it is the PSU itself or what it its connected to
causing this?

[David Clarke]

From the HPC site: (the laser tube) ... it only requires two soldered
joints. However, as typically the tubes run at 20kV or so, these joints
have to be carefully made and be very smooth (to avoid sparking across to
ground).

I looked inside the cabinet this afternoon - a lot of dust around. Does
it need a thorough internal clean? The perforated cover over the PSU
could let dirt settle on the circuit - has it been removed and the inside
checked? (N.B. 20,000V!)

[Chunky]

When the tube was changed we used the crimp connections, as soldering was not working and we did not want to do any damage.
It might be a good idea to remove these connections and re-do them?
That would probably be my starting point.
It could be that the annoying 'draw frame' command juddered the machine and caused the connection to become loose.

Obviously testing power to the laser PSU first would be a start as well.

I'll try and have a look tonight if there is a bit of time,
Matt

[David Clarke]

my notes:

Dirt everywhere - the 'red' HV cable from the PSU to the laser is visibly
dirty. HV tracking could account for the PSU reporting an error?

Dirt everywhere - small fan on RHS of control cabinet, and the rear
extractor fan are both dirty.

Dirt-everywhere - if the inside of the cabinet has been cleaned
previously, has the PSU been cleaned UNDER THE COVER at the same time?
otherwise is could have dirt forming a tracking path?

'knocking out of alignment / disturbing confections'' -unlikelyy to cause
this error?

OR fault (in PSU itself) orcausedd by external bad connections such that
the two LEDs (power line sensors, rather than actually indicators of
errors) are pulsed on and off in sync (until overload shuts the PSU
output down)?

Suggestions: (no particular order)

1. measure / monitor LV output(s) from PSU - do these track the LEDs?

2. clean / wipe / airline blow out dirt and dust. SCRAPE the various fan
blades clean.

3.disconnectt all cables from PSU except mains input. Does LED still
flash? If so, the PSU itself is faulty, else is causedbyt some other
circuitry. EXCEPT that many switching suppliesdon'tt like being
powered-up with no normal load - this may in itself upset the PSU?

David Clarke.

[Chunky]

Update on the Laser wierdness:
Its still out of order....

The symptoms are that the 5V power starts up and then drops out down to zero. This turns on the power and control and the laser pointer lights then they switch off as the voltage drops. This cycle repeats, hence the lights appear to flash.

I opened up the power supply and cleaned it out.
Tested again - no change.
I changed the 7805 5V regulator which was my first idea that it might be blown in some way.
Tested again - no change.

Next steps:
Work out all connections to the power supply. Find datasheet for power supply if possible.
(Power supply made by these people, I think (jinan.com):
http://www.jnhyec.com/en/
http://www.rubylasertech.com/product/html/?10.html
This looks like exactly the same power supply: http://www.tradekorea.com/product-detail/P00295083/40W_CO2_Laser_Power_Supply.html )

Try the power supply (with laser tube attached) with no load/other connections. Does it work?
If it is a power supply problem then potentially fixable or replaceable.

Otherwise narrow down problem to control or laser or steppers....

As a side note:
Interesting info on laser tubes and power supplies:
http://repairfaq.cis.upenn.edu/sam/rconway/35wtkit.pdf

I'll try and get in sometime on sunday to have more of a play, but dont let that stop others trying out things.

Matt

[Chunky]

More of an update on the laser cutter problems (with thanks to David Clarke for ome of this info):

The PSU board is B04837 from en.jnmydy.com.
It looks incredibly similat to this PSU:
http://en.jnmydy.com/products_detail/&productId=200e1bf3-2114-45c6-b797-a67c3343a3b6.html
Which is a 40W PSU for laser engravers, but I cannot be sure without more details and it seems to be very hard to find them using the power of the interweb.

This board should give out 5V @1A, 24V @1A and 20kV @20mA.
The 5V light flashes in time, but the 24V indicator LED never switches on.

I cannot find a 24V regulator IC. There is a large plastic component with no markings apart from the web address (www.jnmydy.com).
There is a 12V regulator IC.
There is also a 'Power Switch IC' (http://dalincom.ru/datasheet/5L0380R%20%28KA5L0380R%29.pdf), but I dont think that is the issue....

I have tested the PSU with no other connections onto the board. The 24V LED indicator still does not switch on.
I am pretty sure it is a PSU problem (but cannot be 100% without a circuit diagram or more circuit specifications).

I would suggest (Dominic) we look into the cost of a replacement PSU board, going directly to the maunfacturer with their PCB code number.

I'll have a bit more of a play.
Later,

Matt

[Chunky]

More details:

Here are some more diagrams for the PSU:

http://en.jnmydy.com/comcontent_detail/&FrontComContent_list01-1285720952066ContId=9b9300f1-c54e-4732-bb2f-b4dd11979e0d&comContentId=9b9300f1-c54e-4732-bb2f-b4dd11979e0d&comp_stats=comp-FrontComContent_list01-1285720952066.html

The Chinese version of the website has an image of the exact same power supply:
http://www.jnmydy.com/products_detail/&productId=d8ff142e-d905-4e1b-ae96-53cf677a1f42.html

The 24V supply is provided by a TL431A adjustable regulator:
http://www.fairchildsemi.com/ds/TL/TL431A.pdf

I cannot read any voltage going from the transformer into the 24V regulating circuit. This might mean the transformer has gone, for some reason.

I think I have spent enough time on it now and I dont think it is an easy fix.
If anyone else would like to test out their fault finding skills then please go ahead.

My solution would be to get a new PSU board.

Hopefully we will have a working laser soon,

Matt

[James Hayward]

Thank you for all your hard work Matt! just for my interest, what's the 24V used for?

J

[Matt Lloyd]

quick guess to power the steppers

'RepRap' Matt

[Phil Parry]

Hi Matt,

The TL431 is a voltage reference, there will most likely be another IC
somewhere,probably a UC3842 or similar.

If so, the circuit will be something like the one shown here:
http://www.badcaps.net/forum/showthread.php?t=20675 .
Check that pin 7 of the UC3842 has around 16V on it - at startup it is
fed from the rectified mains via a high value resistor that often goes
open circuit (be careful as this is on the mains side of the PSU).

Other common problem areas are the IC itself, the MOSFET driving the
transformer, and the optoisolator. All of course assuming that the
rectified mains (~340V DC) is OK.

If you're still stuck, I'd be willing to take a look tomorrow or Weds
(evenings) if you like, but as a new member I've never touched the laser
cutter before so would appreciate you or someone else being there too,
if the PSU isn't still removed from the machine.

Hope this helps!
Phil

On 2013-05-27 20:12, Chunky wrote:
> More details:
>
> Here are some more diagrams for the PSU:
>
> http://en.jnmydy.com/comcontent_detail/&FrontComContent_list01-1285720952066ContId=9b9300f1-c54e-4732-bb2f-b4dd11979e0d&comContentId=9b9300f1-c54e-4732-bb2f-b4dd11979e0d&comp_stats=comp-FrontComContent_list01-1285720952066.html
>
> The Chinese version of the website has an image of the exact same
> power supply:
> http://www.jnmydy.com/products_detail/&productId=d8ff142e-d905-4e1b-ae96-53cf677a1f42.html
>
> The 24V supply is provided by a TL431A adjustable regulator:
> http://www.fairchildsemi.com/ds/TL/TL431A.pdf
>
> I cannot read any voltage going from the transformer into the 24V
> regulating circuit. This might mean the transformer has gone, for some
> reason.
>
> I think I have spent enough time on it now and I dont think it is an
> easy fix.
> If anyone else would like to test out their fault finding skills then
> please go ahead.
>
> My solution would be to get a new PSU board.
>
> Hopefully we will have a working laser soon,
>
> Matt
>
>
>
> On Monday, May 27, 2013 7:36:43 PM UTC+1, Chunky wrote:
>
> More of an update on the laser cutter problems (with thanks to
> David Clarke for ome of this info):
>

> The PSU board is B04837 from en.jnmydy.com <http://en.jnmydy.com>.

> It looks incredibly similat to this PSU:
> http://en.jnmydy.com/products_detail/&productId=200e1bf3-2114-45c6-b797-a67c3343a3b6.html
> <http://en.jnmydy.com/products_detail/&productId=200e1bf3-2114-45c6-b797-a67c3343a3b6.html>
> Which is a 40W PSU for laser engravers, but I cannot be sure
> without more details and it seems to be very hard to find them
> using the power of the interweb.
>
> This board should give out 5V @1A, 24V @1A and 20kV @20mA.
> The 5V light flashes in time, but the 24V indicator LED never
> switches on.
>
> I cannot find a 24V regulator IC. There is a large plastic
> component with no markings apart from the web address

> (www.jnmydy.com <http://www.jnmydy.com>).

> There is a 12V regulator IC.
> There is also a 'Power Switch IC'
> (http://dalincom.ru/datasheet/5L0380R%20%28KA5L0380R%29.pdf

> <http://dalincom.ru/datasheet/5L0380R%20%28KA5L0380R%29.pdf>), but

> I dont think that is the issue....
>
> I have tested the PSU with no other connections onto the board.
> The 24V LED indicator still does not switch on.
> I am pretty sure it is a PSU problem (but cannot be 100% without a
> circuit diagram or more circuit specifications).
>
> I would suggest (Dominic) we look into the cost of a replacement
> PSU board, going directly to the maunfacturer with their PCB code
> number.
>
> I'll have a bit more of a play.
> Later,
>
> Matt
>
>
>

> --

[David Clarke]

As a final determination that is it the PSU - when there are no
connections other than mains power, with the 24V LED off, does the 5V LED
still /flash/?

This would definitely place the fault in the PSU. If, though, 5V is
stable it could be that the 24V supply is turned on/off under control of
the other PCB (as is the 20KV output), and a fault there or in the
stepper motor(s) could still be where the fault is.

[Matt Lloyd]

form my memory of reading up on the connections between the PSU and logic board there is no Enable for the 24V

'RepRap' Matt

[Dominic Morrow]

I'm going to try and buy a new PSU.

Dominic

Sent from my iPhone

[Chunky]

Hi Phil,
Thanks for the detailed info.
I'll check the things you suggest. It would be great if you'd like to help out. I'll be there tonight (wednesday), so maybe that would be good?

Sounds like you have looked at one of these in detail before....
Cheers,
Matt

[Matt Lloyd]

just a thought if its just the 24v & 5V rail thats dead we could stick separate PSU in there to feed the separate rails

'RepRap' Matt

[Phil Parry]

Hi Matt,

I'm now busy tonight I'm afraid.  I hope be at the space on Saturday, so if things aren't too busy with the open day. I could take a look then, or Sunday if that's easier.

I've fixed plenty of switch-mode PSUs before (although I'm now in IT, I was in the electronics business for a long time).  I've never worked on a laser cutter, but it sounds like a fairly normal PSU (if you can call 20kV normal :P)

RepRap Matt's idea is a possibility if it's not easily repairable, or if Dominic does buy a new PSU, maybe this one could be used in the new laser I think there was talk of building...

Cheers
Phil