PSU failure  

RE: PSU failure

Posted by: @adam-s48

Running an original Mk3 on a PETG 100% fill print (to test geometry for something I want to make transparent) and I came to find the printer off and stalled mid-print. I pulled the PSU fuse and found it had failed. I replaced with another of the same rating, and no luck. There is power to the surge protector that it is plugged into. I assume this is a failed PSU? What do you recommend as next steps? Did the 100% fill cause it to overwork the PSU from too much heat being continuously required? I don't know when it shut off. When I got there, PSU was warm, but not hot.

I've seen some other complaints of the PSU being unreliable and recommendations for a Mean Well alternative. Any up-to-date advice? Anywhere else I should look in terms of troubleshooting before I go out shopping for a new PSU?

Printer is 1.5 yrs old, so I assume all out of warranty.

Thanks,

Adam

 

I would measure the voltage at the output. If there is no voltage there, I suspect that the 11/2 years old power supply is defective. I would replace the original Prusa power supply with this one:

https://www.meanwell-web.com/en-gb/ac-dc-single-output-enclosed-power-supply-output-rsp--320--24

The powerpanic board also works with the meanwell power supply:

power_panic_replacement

RE: PSU failure

Thanks for the links. Tested the PSU and looked through the files. Seems a good alternative. Two questions:

1. How well does the Mean Well unit mount to the MK3 frame? Close enough for wiring or do I need to make new / longer cables?

2. Is there an existing mounting setup for this PSU (since it seems to be used by others already) or do I need to design one? 

Thanks again,

Adam

RE: PSU failure

@adam-s48

Don't know about the RSP series, but there is definitely cases and mounts for the NES and LRS series.

RE: PSU failure

@adam-s48

If you attach the meanwell to the original place, the cable lengths should fit. There are templates for a suitable housing at thingiverse:

https://www.thingiverse.com/thing:2863826

https://www.thingiverse.com/search?q=mk3+meanwell+320&type=things&sort=relevant

RE: PSU failure

@karl-herbert

Ordered PSU. Much appreciated for the thingiverse link. Hope to be back up this week 🙂

Adam

RE: PSU failure

Printing housing now. Before I go back to what I was printing when the last PSU blew, is there anything I was unknowingly doing wrong, or was the PSU on it's last legs anyway? I was printing a small test part at 0.05mm height with 100% fill in PETG using the Prusa PETG profile. Parts were not large. Printer had only run for ~1 hr. 

In short, it was the PSU, not the model, that caused problems, right? Any thing else I was doing push it over the edge / likely to push the Mean Well over the edge too? (I assume not, I assume the Mean Well is higher quality and more durable, but I want to check before doing something foolish).

Thanks,

Adam

RE: PSU failure

@adam-s48

Higher temperatures, especially bed temps, and cooler room temps will put more stress on the power supply, as does having 110/120VAC power.  Older firmware, before the PWM changes for the bed, could also potentially add some stress.  Other than that, it's just a matter of time and random chance.

It's not so much a quality issue.  The Meanwell supplies most people have used aren't really any better quality.  In fact, if you take them apart, they will look very similar.  The original Prusa supply was a bit undersized, from a normal derating perspective, and one of the parts was undersized for the usage profile of a 3d printer.  In that regard, the higher capacity Meanwell gives more headroom.  

While its always possible to have a random failure, I don't know of anyone that reported power supply failures after switching over to one of the Meanwell units.  I've been printing with PLA and PETG for over a year on my Meanwell.

RE: PSU failure

@william-m51

Thanks. Good to know. Hopefully the headroom solves the problem.

Adam