Hesine prusa i3 forced into dry run

Hi,
I have bought a 3dprinter online but it's being forced into "dry run" whenever i try to change it ( on the printer with display ) it snaps back from off to on everytime i try to change it.
i have no heat. none in the heating bed and none in the extruder..
So i can't print.. any suggestions?

Cheerio's!

Jay,

I think you are going to have to be a little more descriptive about your problem.

it's being forced into "dry run"
Meaning the hotend header is being shut off?

whenever i try to change it ( on the printer with display )
it snaps back from off to on everytime i try to change it
Change what?

I think what you are saying is that both your hotend header and bed heater shut off almost as soon as you turn them on. I'm guessing you have a power issue. The heaters use more power than anything else on the printer. I'm guessing your power supply is browning out and your whole board is resetting. Put a volt meter between the + and - of the power supply and perform this test again. Note if the voltage dips way down once you turn on the heaters. Try one heater at a time and see how much effect each of them has on the voltage.

Well you nailed it

I try to shut change "dry run" from "on" to "off" but it changes back the whole time.

I'll check the power!
Thanks!

Ah, I see. Dry run is a setting in the firmware. Sorry, never used it. So is there an indicator in your host software or lcd that shows rather this setting is turned on or off?

Yes correct it's a setting in the firmware and unfortunately it's turned on..

I just took apart the heatbed (red reprap plate with an aluminum plate on top) and i see there that the thermistor wires are not connected to each other
is that correct?
because in the extruder they look like they are connected..

OK with the thermistor wires maybe not being connected, perhaps the firmware flips on dry run for safty whenever it can't read from the temp sensors. I don't know what temp sensors you have, but if you have just the standard 100K termisotr witout any exta fancy boards between it and the controller, then the two leads of the thermistor just go straight to two different pins on the controller. Same for both the heated bed and the hot end. They should ever be shorted together.

What firmware are you running?
What controller board do use?
What temp sensors do you have?

So the wires of the thermistor should be seperate?
Should i tape them off? because with all the metal around them they will "connect" anyway

I dont have very much information from the vendor but i managed to get a few words out of them..
I know i have a Melzi V2 motherboard and when i boot it it sais "Omni_1.4" and "M505"

OK, so here is the reprap page for the Melzi. Lots of good stuff on there.

I can't figureout the firmware based on Omni. The link above provides a link over to a RepRapPro Page which in turn provides a link to a github repo RepRapPro git repository for Huxley and monochrome Mendel which says it's marlin. There is probably some kind of command you can run to figure it out, I'm just not farmiluar with it.

Yes, the leads on the termistor need to be insulated and the wires all the way to the controller need to be insulated wire. Most peope have some realy skinny PTFE tubing to slide over there thermistor legs so they won't short together. I didn't have this on my first one, but did have some kapton tape that I used.

Based on the pics on the reprap menzi page it looks like the right two connectors on the board are for your temp sensors. One lead goes to each crew of the connector. Once you get them connected right and not shorting, you also have to tell your firmware which temp sensor your are using. If this isn't done and it isn't defaulted to the one you have it won't be able to read them right and still won't work right any way.

I would get the vendor to give you a link to the firmware.

Edited 1 time(s). Last edit at 07/20/2015 11:13AM by appdev007.

okay so i took the thermistor out and put a new one in. it fixed the problem
So i think my system was indeed forced into save mode (dry run) because a sensor was broken!

thanks for the help! been at it for 4 full days i'm glad it works now!

Cheers!

Awesome! yeah it should keep your hot end or your heated bed or causing fires. You don't want those things run away and get as hot as it wants to. Good luck.