Hot End Temps Falls Short

[BuildingBuda]

Hi, I've had the Max v2 for about five months now and had no real problems other than replacing the thimester? (suckers just so small and thin) but now the hot end is giving me fits.
About 2 weeks ago, it stopped reaching working temp. Temps will get anywhere from 23 to 18 degrees to working temps and then stop, hover around that and then start dropping.
Now here is the part that has me really going nuts, when I run the PID to test the hot end, it works fine like nothing wrong!
So I've run the PID test, set the temp manually at the printer, went to print connected and disconnect from computer (win7), checked the wiring at the hot end and board (which is fine), so
right now the PID test is the only thing that will get up to operating temp. Any ideas on how to solve this would be great (btw it's a stock printer) . . . . . thanks.

[Mac The Knife]

Have you tried printing without the bed heated? Yes, the print won't stick, but if the hotend gets up to temperature that way, I would look first at where the power connects to the printer, make sure the connections are tight, they have loosened up for some people. Second would be to measure the power supply voltage when both the hotend and bed are heating.

[BuildingBuda]

Thanks MTK, I checked the power connectors on the board and some of them were loose. Next I tried to print w/the bed heating up and when the temp stop rising at about 180 something I turned the bed temp down to 0. The temp did get up to within 3 deg (set at 200 got to 177/8) so still no printing. I don't have a volt meter and not sure which one would best serve me since I've never had a use for one. I'm guessing that the readings should be between a certain number and if so what would that be if both bed and hot end are heating up?

[bot]

Check the connection near your hotend, where you crimped the resistor leads to the 18 gauge wire. I bet it's charred and falling apart. Time to replace and redo that, I bet.

[duvdev]

take a mulimater and check the resistance on the hotend resistors I think you shoud have a reading of about 3.5 to 4 ohms.
if not then one of the resistors is nor working

[BuildingBuda]

Thanks all, after closer inspection of the hot end, both leads and trimester(I know it's spelled wrong) were wobbling in their sockets. So instead of going through this
every two or three months, I'm thinking to go with the e3d v6 hot end. Not sure if I want to with the 24v or stick with the 12v and keep the same power supply.
I'll read through the form to see what others have to say about it.
Again, thanks

[BuildingBuda]

Hi all, I'm back.... so after pulling all the leads from the board checking for charred ends/loose connections and reseating them, I pulled
the heated bed and checked that. With out routing the wires just connected them and tested again. Hot end heats up fine reached temps
no prob. As soon as the bed temp is turned on the peek fan slows down and hot end temps start dropping. I checked the fuse which is
fine. Could it be the power supply or some other thing on the board that's not regulating power correctly? BTW the bed reaches temp
regardless.

[K.E.N.]

Howdy, had to work on that problem a few week ago, Yes, you need a cheap multi meter, you can order one from harbor freight or get a cheap one from Wal-Mart or Radio Shack if they did not close around your area. Check for 12 volts on the output of the power supply, voltage should be about 11.7vdc or more, or system will not heat right... Next, check for 3.4 ohms at the print head for the heater resistors, should be able to find a bear spot on the resistor leads easy enough, be aware though, that the resistance can change on the resistors a little, so they may read about 4.2 ohms over time. Check the resistance of your meter leads by setting to the lowest ohms reading and make sure they meter leads read 0 ohms, if not take that difference into account when testing low ohms resistances. If the resistance is say 6.8 or more, then you have an open resistor in the heated print head. By the way, use a digital multimeter, not a old anolog or you can't take a good low ohms reading OK. Now that out of the way, I have found that most of the great power supplies for computers can very on there 12 volt rails up to 1.5 volt lower over months of use. I work on a lot of old computers and find that true. Will make you thing that there is something wrong with memory and such when that happens, that's not always true, just power issues, as low power out of the different rails of the power supply, oh well. Now that said, if you have low voltages and not bad heaters, there is a true adjustable power supply out there that will fix the problem period. Get it through Amazon, Name of MegaWatt, has 30amps out with a 33amp surge, more than enough power for what is needed. I have 2 RMv2's and both now sport this power supply, love them, can be set to the voltage you want and stay that way, and if you ever want to adjust the voltage out for any reason, you can. I run my power supplies at 12.8 volts to make sure the heaters can do there job always and deal with no tweaking of speeds to get enough filament out of the print head at all times, if anything, I now run at speeds of 120% and extra flow at 102% with great results, of course I am using PLA for most of my projects, the extra speed keeps the filament from stringing bad. There is 2 things to do to the filament feed if you are up to it, the first is mount a copper heat sink on the back side of the feed motor with a fan, my unit I found a 50mm size, works great, hold the temp down to about 20 degrees above the surrounding air. Second if you are using 1.75 mm filament, take the feeder that pulls the filament and pushes it to the print head off and notch the middle evenly all the way around, can do that with a very narrow dermal wheel stone, I mounted my feeder on a drill bit and ran the drill at a high speed, placing the narrow stone at the very middle of the feed to wear it down only wide enough that both sides of the feeder grabbed the filament with the middle still able to pull some, that stopped that taking bites out of the filament causing some of my jam-ups in the tubing. For now, that's all I got, beside making ya tired of reading, have a nice day! K.E.N.

[geneb]

Dude. Paragraphs!



g.