Error8 issue, any help please

DonoG · June 25, 2026, 4:20am

Good day Nicholas,

I’m not able to disconnect the switch as it is part of the module. I did disconnect the probe that is connected to the switch and this is the reading received

One thing I would like to note which may open some insight to this issue. When I connected my laptop to the machine and powered up the machine, i had not connected power to my module and with no power the same error 8 occurred which is what tou see above. Only after did ishut down the laser and power up again to initiate the ? command.

I did test for continuity and the switch appears to be fine. Do you perhaps have any ideas?

The manufacturer has eventually come back to me after being on a national holiday and all they say is I need to replace the mainboard and all the switches. Do you have any thoughts on this?

Cheers Donovan

DonoG · June 25, 2026, 4:23am

The consol message did not come through on my previous message, please see below.

Waiting for connection…
Waiting for connection…
ok
[VER:1.1h.20230501:]
[OPT:VNZHDL+I,254,2048]
Target buffer size found
ok
[G54:0.000,0.000,0.000]
[G55:0.000,0.000,0.000]
[G56:0.000,0.000,0.000]
[G57:0.000,0.000,0.000]
[G58:0.000,0.000,0.000]
[G59:0.000,0.000,0.000]
[G28:0.000,0.000,0.000]
[G30:0.000,0.000,0.000]
[G92:0.000,0.000,0.000]
[TLO:0.000]
[PRB:0.000,0.000,0.000:0]
ok
Homing
ALARM:8
Homing fail. Cycle failed to clear limit switch when pulling off. Try increasing pull-off setting or check wiring.
Grbl 1.1h [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
<Alarm|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
[MSG:Caution: Unlocked]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
Grbl 1.1h [‘$’ for help]
ok
[VER:1.1h.20230501:]
[OPT:VNZHDL+I,254,2048]
Target buffer size found
ok
[G54:0.000,0.000,0.000]
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
Homing
ALARM:8
Homing fail. Cycle failed to clear limit switch when pulling off. Try increasing pull-off setting or check wiring.
Grbl 1.1h [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
<Alarm|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
[MSG:Caution: Unlocked]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
ALARM:1
Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended.
Grbl 1.1h [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:ZZ2>
?
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:ZZ2>
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:ZZ2|WCO:0.000,0.000,0.000>
ALARM:1
Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended.
Grbl 1.1h [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>

Aaron.F · June 25, 2026, 7:20am

Did the Y axis move towards the limit switch and touch off when you entered the $HY command?
And the same for the X axis with $HX?

Then, you should be able to home X and Y together with this command: $HXY

If this is what you meant by “power module”, this needs to be connected. If it isn’t, that would explain the ALARM:8

DonoG · June 29, 2026, 7:31am

Hi AaronF,

Yes the $HX and $HY does home to the limit switch on those axis. I’ll try the $HXY and let you know.

In this image I’m pointing to the module cables I had disconnected.

MikeyH · June 30, 2026, 1:36am

After that, try $HZ as well. I say this because we have constantly seen “|Pn:Z|” in your postings.

NicholasL · June 30, 2026, 4:05am

Yes, I don’t think you managed to find and disconnect the touch probe switch? Which I think we had determined to be the cause of the Pn:Z input signal (or could be a motherboard problem). I see a couple of other sets of 2-wires in the back? where do they go?

DonoG · July 1, 2026, 6:53am

Hi NicholasL,

Heres what I get when i execute the $HXY. I need to mention once this error kicks in, i have to restart everything as the laser becomes unresponsive even though Lightburn show something is happening.

Waiting for connection…
ok
[VER:1.1h.20230501:]
[OPT:VNZHDL+I,254,2048]
Target buffer size found
ok
error:8
Grbl ‘$’ command cannot be used unless Grbl is IDLE. Ensures smooth operation during a job.
Homing
error:8
Grbl ‘$’ command cannot be used unless Grbl is IDLE. Ensures smooth operation during a job.
<Home|MPos:0.000,0.000,25.005|FS:0,0|Pn:Z|Ov:100,100,100|A:S>
$HY
error:8
Grbl ‘$’ command cannot be used unless Grbl is IDLE. Ensures smooth operation during a job.
<Home|MPos:0.000,0.000,25.005|FS:0,0|Pn:Z|Ov:100,100,100|A:S>
Grbl 1.1h [‘$’ for help]
ok
[VER:1.1h.20230501:]
[OPT:VNZHDL+I,254,2048]
Target buffer size found
ok
[G54:0.000,0.000,0.000]
[G55:0.000,0.000,0.000]
[G56:0.000,0.000,0.000]
[G57:0.000,0.000,0.000]
[G58:0.000,0.000,0.000]
[G59:0.000,0.000,0.000]
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
Homing
ALARM:8
Homing fail. Cycle failed to clear limit switch when pulling off. Try increasing pull-off setting or check wiring.
Grbl 1.1h [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
<Alarm|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
[MSG:Caution: Unlocked]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
$HY
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
Starting stream
[MSG:Pgm End]
Stream completed in 0:00
Starting stream
[MSG:Pgm End]
Stream completed in 0:00
<Idle|MPos:50.000,50.000,0.000|FS:0,0|Pn:Z>
$HXY
<Idle|MPos:50.000,50.000,0.000|FS:0,0|Pn:Z>
error:3
Grbl ‘$’ system command was not recognized or supported.
<Home|MPos:50.000,50.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>

When I enter the $HZ this is the feedback from the consol.

Waiting for connection…
ok
Grbl 1.1h [‘$’ for help]
ok
[VER:1.1h.20230501:]
[OPT:VNZHDL+I,254,2048]
Target buffer size found
ok
[G54:0.000,0.000,0.000]
[G55:0.000,0.000,0.000]
[G56:0.000,0.000,0.000]
[G57:0.000,0.000,0.000]
[G58:0.000,0.000,0.000]
[G59:0.000,0.000,0.000]
[G28:0.000,0.000,0.000]
[G30:0.000,0.000,0.000]
[G92:0.000,0.000,0.000]
[TLO:0.000]
[PRB:0.000,0.000,0.000:0]
ok
Homing
ALARM:8
Homing fail. Cycle failed to clear limit switch when pulling off. Try increasing pull-off setting or check wiring.
Grbl 1.1h [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
<Alarm|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
[MSG:Caution: Unlocked]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
$HZ
ALARM:8
Homing fail. Cycle failed to clear limit switch when pulling off. Try increasing pull-off setting or check wiring.
Grbl 1.1h [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
[MSG:Caution: Unlocked]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
$HX
ok

The wires you are pointing towards are the Z axis stepper motors wires.

The only feedback I’m gett8ng back from the manufacturer is that its the mainboard. They’ve said thos without any attempts at establishing that this is the route cause.

MikeyH · July 2, 2026, 1:43am

Did they mention anything about a replacement?

DonoG · July 2, 2026, 3:29am

Yeah, they said i need to replace it and sent me a cost.

NicholasL · July 2, 2026, 3:48am

Could be mainboard, could also be one of the z-limit switches not working - either the upper Z-limit switch, or the touch probe switch, or the wiring. Since the problem came up after your monthly cleaning?, this could be a wiring issue - something knocked perhaps.

When I asked if you could disconnect the touch probe you said:

I don’t really understand what you meant by “disconnect the probe that is connected to the switch”.

So I would still be interested to know what happens if you disconnect the connections you are pointing your finger at in your post #24 - and see which connection if disconnected might cause the Pn:Z to disappear, check with ?.

Basically, if you could confirm:

? Pn status (all the characters between ‘Pn:’ and ‘|’) with the touch plunger pressed in, and status when you check again with the plunger out.
? Pn status with the upper Z limit switch pressed in and the status when you check again with the switch out.
For each of the two wiring plugs at the top of the laser module, one at a time: power off, disconnect the plug, power on, send ? (the machine will be in an alarm state from failed homing but ? should still work), record the Pn: reading, then power off and reconnect before doing the other plug (please don’t unplug these with the machine powered).

These three results will help confirm whether the fault is in a switch, the wiring, or at the board as the manufacturer says. If the motherboard and switches will be replaced under warranty then it’s a no-brainer - as long as wiring & connectors come with the switches.

P.S. I’m assuming that a Pn:Z in the status line at idle is not normal, it may be worth asking iKier directly (since you already have an open support ticket) if Pn:Z at idle is expected on this model.

DonoG · July 14, 2026, 5:45am

Hi Nicholas,

I haven’t had any feedback from Ikier in relation to the fact that the Pn:z status is idle.

Further more I’ve just returned from a trip and haven’t had a chance to run some of the test you requested, I see this thread closes soon and i won’t have that info until tomorrow morning. Do I start a new thread with that info?

Cheers Donovan

NicholasL · July 14, 2026, 6:05am

Hi Donovan, no problem, you can keep posting here, I just made an adjustment to the timer on this topic.

DonoG · July 15, 2026, 7:28am

Hi Nicholas,

Here is the info you requested.

In this image I’m pointing to the probe I mentioned thats attached to the limit switch. The limit switch is part of the laser module but the probe can be removed.

Here are the readings when I press the probe in

And here are the readings when I release:

ALARM:1
Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended.
Grbl 1.1h [‘$’ for help]
[MSG:‘$H’|‘$X’ to unlock]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>

There is no upper limit switch which I have on a few occasions sent the Z axis to the max and it keeps going. Rather dangerous.

I first remove this cable and got the following reading

<Alarm|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
[MSG:Caution: Unlocked]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
?
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
Grbl 1.1h [‘$’ for help]

This was followed by the cable in the next image and the reading was

<Alarm|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>
ok
[MSG:Caution: Unlocked]
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z>
ok
<Idle|MPos:0.000,0.000,0.000|FS:0,0|Pn:Z|WCO:0.000,0.000,0.000>.

Hope that all makes sense to you.

Cheers Donovan

NicholasL · July 15, 2026, 11:26am

Thanks Donovan,

That makes it very clear that the ‘Z2’ is the touch probe - which is functioning correctly.

That leaves the mystery ‘Z’ pin input which will surely be the Z axis upper limit home switch which must be present somewhere, you might need to lower the head to see it?