Hello
I heard a big clack by turning on the K40, and I discovered that, you think we can replace the component? Or you have to change all the food?
Thank you all
Jean Philippe
That was a fuse. If it blew something inside but be terribly damaged.
Main fuse blown. It’s a common problem when supply dies. How old is it?
a few hours only … K40 not used since many weeks and boum
@Jean-Phi_Clerc
Other than try and get replacement from your vendor…
…you have a couple of routes depending on how electronics savvy you are.
If you are not good at testing electronic parts.
A. replace the supply $60-70
If you are good at Repair:
B. Replace the Flyback as a stab in the dark $30
C. Look for damage or shorts then replace the bad parts. These components:
…Rectifier bridge (common)
…Power transistors
…Power Diodes
…$20-30 depends on how many bad parts.
D. The problem could be B-C so the supply could end up being more expensive than a new one.
WARNING: This unit outputs lethal voltages so I do not recommend repairs unless you are skilled at HV electronics.
…
Are any pars other than the fuse charred, if so post pictures pls.
Where are you located?
Was the laser firing when fuse http://blew.if no than could be limited to dc side of power supply ,that what powers the stepper moters and control board
Change fuse to same size new one and remove middle and right green connector to eliminate external to power supply problems, if fuse don’t blow problem elsewhere
@Jean-Phi_Clerc That is a very common problem in this type of machines. I had the same problem some time ago and they helped me solve it. I leave you the link to the conversation where the answers are: https://plus.google.com/105896334581840652176/posts/LqVp55MbtpE
In my case, what caused the fuse to burn was the general switch, which turned on the machine, jumped a spark and caused a short circuit in the power supply. I replaced the main switch and the emergency switch with good quality ones. Then I isolated the power supply, changed all the wiring connectors and finally, I soldered the burned fuse and the bridge rectifier, since it had also been burned.
With all this the problem was solved and since then the machine worked perfectly until one day it stopped working again. This time it was the high voltage transformer. I changed it for a new one and for the moment the photo works perfectly again.
@Fernando_Bueno I watch the LPS failures pretty carefully. My guess is that your switch was a separate failure, but of course still needed replacement :).
Most failures seem to be related to the HV flyback transformer. Sometimes it is accompanied by a bridge rectifier failure and sometimes not. Sometimes the bridge rectifier fails and the flyback does not. Sometimes just the flyback.
@Jean-Phi_Clerc if it was me I would replace the fuse and the bridge rectifier if nothing else is charred.
See: http://donsthings.blogspot.com/2017/01/k40-lps-repair-and-test.html
Beyond that repair, a new supply may be the long term cheaper route.
@donkjr The change of the main switch and the emergency button may not be necessary (especially the latter), but for the price of new, I think it was worth it, especially if I avoid any future problem. In any case, I think the important thing is to use quality components when replacing them.
@donkjr , i leave in France,
Normally, I will have someone who can verify the components one by one, we will see what is dead. A big thank you to all for your opinions
@Jean-Phi_Clerc Just a note on testing components. The Flyback primary can be tested with a DVM (low ohms) however the secondary will likely read OPEN since it has a HV diode in series. If all else is good then it is likely the flyback!
After my LMS blew the fuse I discovered that the second ground wire had disconnected. Bought an $80 PS from Ebay because the vendor didn’t respond. The K40 has worked fine. Don Kleinschnitz, I haven’t rec your address so I can send the bad LPS to you.
@bbowley2 whoops I sent it again via PM on G+.
Hi all, i come back, was away since few days, and my problem with the K40 wait after me 
i found this fuser : http://www.conrad.fr/ce/fr/product/537935/Mini-fusible-ESKA-887124-temporis-T-sortie-radiale-rond-5-A-250-V-1-pcs?ref=list (french) do you think it is the good one
@Jean-Phi_Clerc
#K40lpsrepair
First the warning:There are LETHAL VOLTAGES in the K40 HV power supply I do not recommend opening the cover and attempting repair.
…FUSE
That fuse should work but I have never used that one.
Below is a post with information on repair including an axial fuse link on amazon, which might be an easier install.
It also has updated schematics.
You can also install a 5A car blade fuse and holder which has the advantage of being easier to get and is replaceable without an iron. You can usually get the holder and blade at car parts stored.
I install a reset-able one during a supply repair because I have found that I blow them a lot during troubleshooting and soldering is annoying.
… Replacing bad components
I have been working on +bbowley’s bad supply as a part of learning how these supplies operate an fail.
The AC bridge is a common failure which blows the fuse. Multiple things can cause the bridge to draw to much current so its likely that you will have to replace more than one part and you may blow another fuse and bridge in the process. There are links to parts in the post below.
I have not had time to create a proper repair procedure but if you do decide to try a repair here are some hints:
*DO THIS WITH THE POWER OFF AND THE HVT UNPLUGGED OR UNBOLTED. DO NOT ATTEMPT VOLTAGE MEASUREMENTS WITH POWER ON. THE INTERNAL VOLTAGES CAN EXCEED 600 VDC AND METER PROBES CAN ARC, DAMAGING THE SUPPLY AND YOU! *
A. Test the bridge for any shorts on its 4 terminals.
B. Test the 4 diodes on the HV side for shorts
C. Un-solder pin 1 and pin 2 on IC2, test pin 2 to pin 1 for a short.
Replace all parts that have shorts before re-aplying power.
when testing for shorts test with the meter on ohms. Measure one direction and then swap the leads and measure again.
A: Rectifier Bridge: https://photos.google.com/share/AF1QipPVc9xaF8LcHNbrl46U3whrMwHzCraEJwx1Vgnkqlsvi4BWpXAo5oTksov5qoNaCQ?key=N29GY3dXSEtBUTZXeVhYV0ZBelpkVTlVb1QzSGR3
B: HV side diodes: https://photos.google.com/share/AF1QipMN-jOBcc9GgwZAmIw0H4BlNM0NqdOI6BxnV76HkUzGKteAOpqNvzUQeeF-R9EICA?key=SFFKQTRKVXNPdktNT3lWV040WjNYbzI1ZkwzUENn
C: IC2: https://photos.google.com/share/AF1QipPBv-umQ1aw9EOkD2Rso3VQBHhev-SHAmC6k_EjV8IZcXVq2_9DplkNGr73vTq1ww?key=X0dUem13WHpCZXp5MnlLM2UzcjBVMGdTVEtsLXln
@donkjr I’m still alive 
tried to repair but no way, not strong enough in changing components, can you give me a direct link where to buy the correct supply? thanks again
@Jean-Phi_Clerc this link is further up in the post and has part # and supplier links?
http://donsthings.blogspot.com - K40 LPS repair and test
What have you tried to repair, how and with what ?
@donkjr Hi, i’m trying to find exact model for supply for spare, my problem is i have no knowledge in electronics components… have a fuse with me, will test it as soon as possible, my supply is like the picture here if you kno
w where to buy it https://photos.google.com/share/AF1QipPLOjQ3RSf2oZI6UR67ndbRTqFt7RH3_BJVGmyXKttQn3SngfuBwelz1OZapF2kGQ?key=Z0lVOWh1RzEwRzkzVWJnMXVhdm55d1E1ZmpwVHlB
@Jean-Phi_Clerc any of the 40W supply’s you find on line with the same set and orientation of green connectors should work
Examples and where you can get them from:
Aliexpress:
Amazon: