The laser is always on when I close the lid

If I understand correctly you check continuity in both directions with the DVM set on ohms and its is shorted. The other diodes show open in one direction?


You probably can disconnect the diode from the board and see if the IN signal returns. I am guessing that the diode is there to eliminate spikes on the output.

I am guessing the diode goes from the IN pin to either ground or 5V?
Can you tell how the diode is in the circuit?

yes the other diodes are open only in one direction

I removed the highlighted components and there are three in short circuit a diode (SS14G) I had it at home and I replaced the other two components (see photo)
WE 79A are short-circuited but I can’t find them
I tried the controller and now the laser fires even with the connector connected that goes from the LPS to the controller but after the first shot it is always on only after the first shot
now i will try to find these components that i could not find on google i asked some shops if they had any but they have yet to answer me

Are you saying that all the diodes D127, D110, D111, D108, D109 are all shorted???

If so that seems quite unusual.
Did you have any kind of a power problem recently
Did the LPS arch recently?

I could not find data sheets for the WE 79A


This diode should be easy to substitute.

Did I label the pins correctly in this picture…?

I cannot tell from the picture which side of the diodes is the ANODE

It looks like the two diodes coming from inputs TL and IN are connected together on one end???

Can you tell how the diodes are connected and to what?

Can you draw a circuit diagram?

  • Remove the bad parts and with a meter check where the lands connect to.
  • The input lands should be open
  • The other end of the diode land likely goes to 5V, ground or another diode.

I am guessing these are snubber diodes if so we can probably find substitutes.

You could try the laser with all the bad diodes removed but I worry about what the purpose of D54 is!
Can you tell the part # of D54.

When you removed the diodes did they read “shorted” when out of the circuit?

Uploading: photo_2021-09-22_09-13-20.jpg…

I tried with the components disconnected from the board except D54 (diode A7W) and the laser works but after the first touch on the test icon of the control panel the laser is always on

I am looking for the WE 79A component

i read that the controller must be connected to DC 24V 3a I had connected it to a DC 24v 15a maybe this was the problem?

The controller should only draw the current it needs. A larger supply should not be a problem it just has more capacity than needed.

We need to figure out how those diodes are connected.
Can you take a picture of the PCB without the shorted diodes so I can see the lands?

Can you trace the circuit with a DVM on ohms?

Hello, can you ease help me to connect this

To this

Please let us know what you’re trying to connect it to. The more information the better. Thanks!

Sorry, AWC7813 Trocen

Is it wired as the recommended? The two marked in red control current and laser enable. AWC7813 user manual.


TH is the inverted TL. P is water protect.


So if I understand correctly is like this

GND to G
TTL1 to L
PWM1 to IN

Is that correct?

So if I understand correctly is like this

GND to G
TTL1 to L
PWM1 to IN

Is that correct?

Yes… is this not how it’s connected?

Did you download the manual?


Yes I have the manual but something is wrong and I want to double check tomorrow just to be sure and I will be back with updates. For now thanks for your help.

Ok. So I find out what was the problem, a bad wire connection. Thank everyone for helping me out.