Random Reboot Shortly After Power On

Occasionally, and randomly, my glowforge reboots shortly after power on.

I’ve tried using my glowforge with and without a power strip and the problem persists.

So far the glowforge only goes through one self-reboot. Once it self-reboots once it doe not self reboot again.

Can anyone tell me what’s causing this, and if it is a risk to my glowforge’s long term well being?

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How frequently you talkin’? I think this is what it does when it gets an update.

I too share the same behavior. I sent an email to support about 2 weeks ago with requested date/time information; “they are looking into it” is where I’m at.

When your Glowforge powers on it checks for updates. If there are any updates, it’ll install those updates and may reboot if the updates requires a reboot. All of this happens before you’re able to start a print. An update won’t interrupt a print.

I’d like to investigate the reboots you’re experiencing, but I’ll need a bit more information. Could you please let me know the date and time this occurred last? Thank you.

A Power Strip only serves to protect the plugged-in equipment from voltage surges. It does nothing to eliminate noise on the line or to mitigate voltage drops, either of which can upset computerized electronics.

If you think your power is the problem, you should consider a small battery-backed UPS. This would protect you from the same voltage transients and noise as an outlet strip but would also give you a minute or two of “ride through” in the event of a power drop-out.

I can’t say for certain when the last random reboot was, but looking at my log files, I have very small log files at the following dates and times:

3/27/2018 3:24 AM
2/28/2018 2:50 AM
2/24/2018 6:27 PM
1/20/2018 5:05 AM

The 3/27/2018 sounds about right for the last self-reboot, but the time stamp is off.

Vee, I just sent my log files to support@glowforge.com with the subject

Attn: Vee - Log file for Mike10 random reboot issue

On potential clarification – a plain “power strip” provides zero protection against surges – you’d need a surge protector (often found in a power strip form factor) to protect against any type of line surge.

No protection:

Surge Protection (but no battery):



Agreed. But most strips nowadays contain the necessary “MOV” device to suppress transients. It’s a component that costs pennies. But yeah, valid point, make sure the strip you get says “surge” or “transient” protection or it’s not doing anything more than the wall socket it’s plugged in to.

P.S. I use the Pro 700 for my workstation PC where it gives me about 15 minutes run time. The GF is plugged in to a smaller 300VA UPS since I’m just looking for “ride through” on short voltage dropouts, not sustained operation without AC power.

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Have you tried unplugging the UPS while the Forge is attached to it and it is running? You may be disappointed. There are maximum wattage ratings for UPSs, which when exceeded, cause them to shut off immediately. This wattage limit is typically about 60% of the VA rating.

Did you catch the rest of that sentence you quoted?

Good point. You’re right. I’ve switched to a 550VA that’s good for 330W.

Yes, I did. If the load exceeds the max wattage of the UPS, it shuts off immediately. There will be no “ride through.”

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That may not be quite enough for when it the Forge is cutting:

The Forge is rate at 800W, so to eliminate any chance of overloading the UPS and shutting it off, you’d need a 1500VA. That is, unless that 800W rating is very conservative.

Why nearly double the VA? If the power factor was unity VA and W would be the same. To pass CE it should have a PSU with power factor correction and that would make it very close to unity.

see https://www.power-solutions.com/watts-va

The power rating of the UPS
UPS have both maximum Watt ratings and maximum VA ratings. Neither the Watt nor the VA rating of a UPS may be exceeded. It is a de-facto standard in the industry that the Watt rating is approximately 60% of the VA rating for small UPS systems, this being the typical power factor of common personal computer loads. In some cases, UPS manufacturers only publish the VA rating of the UPS. For small UPS designed for computer loads, which have only a VA rating, it is appropriate to assume that the Watt rating of the UPS is 60% of the published VA rating. For larger UPS systems, it is becoming common to focus on the Watt rating of the UPS, and to have equal Watt and VA ratings for the UPS, because the Watt and VA ratings of the typical loads are equal.

What a mess!

The GF should have a power factor close to unity, so you need a UPS with a VA and W rating both bigger than 800 to be conservative, or probably 400 in practice.

Maybe a bit higher than 400 to be safe, since that is what Dan was measuring during cutting operations. If we shoot for 500W, then an 800VA-900VA UPS should be pretty reliable.

Looks like it although how you could legally sell a UPS with VA rating and no W rating that could not accept a unity power factor load I don’t know.

It makes sense to have both ratings or state just state VA and have W the same, but to have an implied power factor of 60% is bonkers. Especially since power factory correction has been mandatory here for IIRC about 10 years for things like computers.

Thank you for helping us investigate this. We’ve tracked down the bug responsible. While we don’t have a fix available now, the behavior is harmless, and doesn’t affect any other aspect of your machine or its operation. Thank you again for letting us know so we could investigate it for you.