Interior fluorescent bulb out

HPC LS6090

Fluorescent bulb stopped working suddenly.
Tube does not look degraded, no poor light output, no blackening at the end of the tube.

Checked the voltage on the supply. 0V, presumably it is 240V AC?

Is there an internal fuse / trip.

Had trouble tracing the cables as they have loads of cables wrapped in shielding in there!
No luck finding a wiring diagram online.


In the power cable there is sometimes a tiny glass fuse. If the power cable is a 3 pin one it’s hidden in the bot that directly attaches to the machine. Open the compartment and check to see if the fuse is blown.

The attached photo isn’t an exact image but it shows the location of the fuse. If I remember correctly it’s a 2a one. Hope it works.



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Thanks Alex, the rest of the cutter is working fine, just the fluorescent bulb out.

Will give it a look… I’m dreading looking round the back of the machine… I’ve been keeping the interior and the front clean… but not the back :scream: :scream:

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On the LS6090 and other larger machines on the right side there is usually a large bay of electrical stuff. Very likely the strip light connects to a switching PSU in there (I was working on a similar machine yesterday).

But if the bulb alone has stopped then its a fair chance it’s just your bulb try replacing that first.

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Got the tube out, both filaments reading ~5.8 Ohm so I think the bulb is OK, don’t have a spare or anything else I can fit it on to absolutely confirm that.

Looks like its head in the electrics bay and tracing. :confounded:
Don’t suppose you know which of the PSU units the lamp is powered from do you?

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I don’t. But if you take a picture I can help work it out… You should have a light switch somewhere, you should check for voltage at the switch too. Also I’d be surprised if you bulb is 240V AC… it’s much more likely to be 24V DC or something like that.

However wire tracing IS the best bet Phill sorry.


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Will go and re-do volts on the wires.

Not found a switch for the light, it comes on when you turn on the master key.

Let me have a look round and I will try and get a decent pic taken.


On most models I’ve seen, it’s on the top next to the “Up and Down” controls for the Z table… however models vary.

Oh you mean the MASSIVE red button with ‘LIGHT’ on it :man_facepalming: :man_facepalming: :man_facepalming: :man_facepalming:

Excuse me, while I go and put my laser back together… :rofl: :rofl: :rofl: :rofl: :rofl: :rofl:

@phillw was the light switch off? Was that the issue?

Yeah, I had got so used to seeing it and never using it… I was blind to it.

Still on the bright side, the lamp and fixture is now clean, very clean.
The box with all the electrics in is also clean. One sticky pad that holds the cables in place had come away and was impeding the fan, so that got sorted and the fan cleaned.

I now know the entire layout of that box!!!

Oh and the lamp is 240 volts, judging by the belt it gave me when I went to take out my test wires, having switched the light switch on :rofl: :rofl:.

All is good and I don’t think the laser has ever been so clean!

Cheers for the pointers though!


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Oh dear. Yeah sometimes lighting is linked direct to the mains. I’ll make a note of that myself.

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Next time you are checking it out, I think they might have naughtily wired it up.

The light switch was ‘ON’, but I had not turned on the power key.
When I touched one of the connectors, I got a jolt and the RCD tripped.

Surely this means they have wired up the neutral wire to the switch and not the live?
Unless there are big freaking capacitors lurking in there somewhere, and that’s what I earthed?

Sounds like a death trap.

Maybe one day I’ll take the box covering the switches and motion controls off and have a look see.
Like I say, if there is a big capacitor in one of the power supplies it could have been that.
On past history, I know I’m not that conductive :cowboy_hat_face:, so maybe it was just a cap jolt?

I doubt it’s a capacitor. It’s much more likely to be a poor wiring choice.

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