Premature ATX death? I’ve had this inland 600 Watt power supply powering my printer now for about 4 months. Now it’s getting flakey and I’m ready to pull it before it causes damage to the important bits.
Does it seem odd that a single 12v drain would cause premature death? It’s long enough that it doesn’t really seem like infant mortality, and what little I know about electronics makes me think it might not be properly spec’d for the job.
Buying cheap PSUs is rarely a good idea if you’re not 100% sure about what you’re getting into. The Inland unit is “rated” for 12V/36A (which is more common for 450W units), but since it’s a no-name unit, it’s likely only good for about 20A. It also has a ridiculous efficiency of (up to) 76%. Cheap PSUs often have group regulated rails, so you might be over-volting (and frying) some internal part that runs off the 1.8, 3.3 or 5V rail.
http://forums.anandtech.com/showthread.php?t=2178675
Toss the Inland and get one that is at least rated for 80+ - that usually is a good indicator of a PSU being at least of decent quality.
Looking closer at the labelling, it may also be that I’m running it off part that’s rated at 7.2W, rather than 432W (So, Molex sources for things like hard disks vs. the 12V source for the CPU), I used Molex as I didn’t want to chop the PS up if it wasn’t going to work for me, sounds like it’s been doing more harm than good.
Part of the problem is: there’s little visible difference between a cheap knockoff PSU and a good one. What’s a good source and a reasonable price to pay for a good one? (Now two as the next printer will need one as well.)
Why not just get a real one? http://www.amazon.com/Universal-Regulated-Switching-Computer-Project/dp/B00D7CWSCG/
That’s probably the better and cheaper option. While those aren’t super-high quality either, they seem to be working well for most folks.
Any benefit to going 24v vs 12v?
Less load on the wiring and transistors as well as happier stepper drivers. If the heater elements and your control board are cool with 24V.
RUMBA appears to be, and I’ll spec the plate heater to be 24v…will I blow up a 12v heater cartridge if I double the voltage?
Probably. Plus, instead reducing wiring and transistor loads, you’ll quadruple them.
24V heater cartridges are cheap and ubiquitous, so there’s no reason not to use them when appropriate.
I think it means I’ll buy one of each power supply. 12v for the delta, 24v for the Ingentis/QuadRap
@Mike_Miller you won’t blow up a 12v heat cart as long as you’ve got the settings in Marlin setup correctly. You can set the max duty cycle to be 50% on the hot end, which will keep you good I believe.
I can’t remember what specific setting it is off the top of my head, but it’s in one of the configuration files.
25% would be the correct setting there. That’s probably going to work, but I wouldn’t be comfortable with permanently using that kludge.
@Thomas_Sanladerer it wasn’t duty cycle, I think. IIRC it was PWM. So like a 50% PWM duty cycle when the heater was on…I’ll check into it. You certainly would risk problems if you flashed fresh firmware or something like that, so yeah - it’s a kludge of a solution.
With my comfort level in EE. I’d rather just use the correctly rated components.
@ThantiK P=U²/R (as per P=U*I and I=U/R), so 24V instead of 12V into the same heater (at a 50% duty cycle) is still going to give you twice the heating power. I’m not sure what resolution the firmwares use for their PWM logic (Arduino uses 8 bits / 256 values by default), but only being to use 25% of that resolution might leave you with a fairly harsh PID loop.