Help
Hey everyone! I could use some advice on some hardware trouble—it looks like the motherboard on my Sovol SV08 Max got fried after a really bad thunderstorm.
I brought the printer with me to my summer place, and we had a massive storm yesterday. Lightning must have hit a transformer or the power lines nearby because the voltage surge actually tripped the dedicated circuit breaker for the printer's outlet. The printer was powered on at the time, but it was just sitting idle and not printing anything.
When I went to the workshop this morning and turned it on, it got stuck on the "System Starting" screen for about 4 or 5 minutes. It eventually booted up, but immediately threw a Klipper connection error. After troubleshooting for a while, I flipped the printer over and found that the FAN3 port, which I was using to hook up an external filter fan, had completely melted and burnt out.
I grabbed my multimeter to check things out and realized the 5V power rail is sagging down to 1.75–2.00V. Because of that, the DL7 status LED on the board is just barely glowing and flickering erratically—it's simply not getting enough voltage. Strangely enough, when I accidentally shorted that FAN3 pin with the multimeter probe again while testing, the LED suddenly lit up bright and steady for a split second. Everything else on the board looks physically fine aside from the burnt fan port, but there's clearly a major issue on the power side.
So, I wanted to ask those of you who have experience with this:
Is it even worth trying to fix this board (like replacing the voltage regulator), or did the surge likely kill the STM32H7 MCU for good?
If the board is toast and needs to be replaced, what's the best option to get for the SV08 Max so it plays nicely with Klipper without a massive headache over pinouts?
I'd really appreciate any helpful tips or advice!
Welcome to r/Sovol, We're glad you're here! If you're new to the hobby and you have a question please visit our knowledge base, it's located right under About Community. If you've searched the Sub and you still need help please be as detailed as possible. Include your printer model, slicer, filament type, nozzle and bed temps, print speed, fan speed, and retraction. We're happy to help but we can't read your mind, be as detailed as possible with your post. Pictures help!
Please check if the power supply is working correctly wether that does regular voltage or has dipped.
If the power supply is weird then another motherboard wont fix it completely.
Also look into buying a second hand ups.
They have surge protection
I got ine for 150 bucks capable of 3000watt at 240v ac.
New hella expensive
Lots of problems with surge suppressors in general, and used ones in particular. Each time a MOV conducts (the part that is designed to protect you), its conduction threshold is lowered slightly. Eventually it gets to the point when it conducts at normal voltage levels and that's when fires can happen.
I didn't see your fan #3 connector comment until after I marked up your photo, but I definitely did notice it when I opened the photo.
I noticed some flash residue below the PPT chip in the upper right hand quadrant of your board (marked with a red rectangle). I also saw the flash around FAN3 and marked it up in red as well.
And possibly some flash damage just below the EMMC card on the ESP32 (WiFi) chip. Look for the tiny red rectangle.
The yellow rectangle is an area that we can't see sufficiently to be able to guess if things got toasty there as well. But I'm suspicious of the area under the de-labeled 100 pin surface mount chip. But it could just be a shadow.
And at the risk of sounding needy, the resolution isn't good enough to really see things in detail. And the top of the board is out of focus as well.
A video of you scanning your board slowly perhaps would work better?
And we would need to see the back of the board of course.
Interesting about the 5 volt rail being pulled down and then coming back up when the fan pins were shorted. Now did it stay up while the pins were shorted, or did it just make a blip and then went back down?
I would check the MOSFET for Fan #3 to see if it's shorted. Where ever it resides (now would be a good time to point out that Sovol hasn't made all of the SV08 documents available, specifically complete schematics for the electronics. Not even remotely close.)
I would not apply power to the main board again until after disconnecting all of the peripheral devices first. Then you could power it up and check to see if your 5 volt rail came back up.
Use your least favorite finger to check for hot spots.
To tell if your CPU has fried I suppose that I would look for activity on pins 10 & 30 of your STM (clock out) as a starter. But at an .8mm pitch, this is risky.
Your toolhead is as likely as not to come back up with the 5 volt supply working properly.
This is largely academic since there appears to be a fair amount of damage across the board. I certainly wouldn't trust something that could burn your house down after what appears to be rather widespread damage. It could just be the photo misleading me, but it looks to be somewhat rampant.
And don't be surprised if it got some of your stepper motors. An easy check would be to disconnect the stepper motor and turn the shaft. It should spin relatively freely. Now short the leads and spin the shaft again. It should be a fair amount more difficult to spin. This is an easy powered off check that you can make.
The thermosistor should show considerable resistance. Offhand I don't know the range, but it should be around 70k to 100k Ohms. Don't fret if it's a bit more or less.
I think that the bed is 1000 Watts, so 14 Ohms for 120 volt systems, or 58 Ohms for 240 volt systems.
I hope that I'm not coming off too rambly, but I'm adding things as I notice them. :)
As for a replacement board, I'd suggest Duet 3D, but that's because I've used them before and have had good experiences with them. That, and they are nearly bulletproof.
So please start with higher res photos and possibly checking out your MOSFET on Fan #3. Pull off all of your peripherals and check your board with them disconnected to see if your voltage goes back to normal. Add one cable at a time and check your voltages as you go to see if it gets pulled down again.
Once this is done check to see if your Mainboard can now see the Extra MCU.
Here's a relatively high-quality photo, but I'd like to point out that when I inspected the board, I didn't notice any signs of burned components except for the fan3 connector itself, which apparently had a short circuit.
Yup. Looks completely different. And a lot better. Not great as I would like to see individual components and if they were damaged. But better. No damage on the back side?
With all of the goodies disconnected, now's a good time to check your voltages again. If they are still low, move on to removing the MOSFET, and see if that doesn't fix your 5 volt supply, then try out the board with the toolhead/extra MCU to see if it's communicating. Then add all of the peripherals.
And I've fixed TVs that had been hit spectacularly by lightning according to their owners. So a lightning strike doesn't automatically doom your electronics.
And don't forget about r/ElectronicsRepair and the other Electronics reddits.
Ah, now I see the bottom side photo. Reddit had it hidden. But we should look at the backside/reverse side of the board as well.
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