Did i burn up my heat bed?

[kevo3]

As of late, ive been having heating issues with my print bed. Using both matter slice or the LCD. For what ever reason, it cant seem to get above 86. After first building the printer, i could reach temps as high as 110 no problem, but soon it began to struggle a bit, and eventually, it began to fluxuate around the target temp quite a bit. Now when ever it reaches about 86, it simply stays there there a while. Now this wouldn't be to bad of a problem, as i can easily print at that temp, except, now it will reach the temp, then after a few minutes begin dropping back down to 72. Target temp still stays what ever it was set to, the actual temp keeps going down. Then whenever i update the target , it does it all over again. Ive re solderd the wires a few times now, and ive noticed that the positive one is looking a little rough. The material around the metal is chipping from the heat, and i can see a bit of copper(i believe).Is it possible ive soldererd it so many times, ive destroyed the plate for the wire? or are we looking at another issue? If i have messed it up, is it fixable? or should i begin ordering a new one?

[ccavanaugh]

Measure the voltage at the heat bed when it's first turned on. It could be a weak power supply. It's about the easiest failure mode to check before you start swapping parts.

[kevo3]

Measure the voltage at the heat bed when it's first turned on. It could be a weak power supply. It's about the easiest failure mode to check before you start swapping parts.

i dont have anything on hand to test it with, but i can get something tomorrow probably. Any chance it could also be a PID issue? because after it drops down to 72, it goes right back up to 85.

[Xenocrates]

that almost sounds like more of a thermistor issue, if it's immediate. If it takes a while, then it may be a PID issue, or a loose connection somewhere (such as between the power supply and the rambo, the auto fuse being poorly seated, or loose connectors to the bed, not just the solder connections.) In my opinion, as far as dealing with the chipping on the bed, if you can, get some Conformal coat, and spray the areas where copper is showing to insulate it.

Go ahead and try to get a reasonable multimeter, which can handle at least DC voltage, resistance, and continuity.

Another question. Are you using the older ATX power supply, and if so, is it original or a larger capacity one? If it's the original ATX supply, it may be the cause of the issue.

If the power supply voltage is OK, and gets to the bed unmolested, then it may be an issue elsewhere. Check for continuity between the pad on the bed and the rambo terminal for each wire. Then check the resistance of the bed itself. Disconnect power before doing this. If you don't, you may blow a fuse on the rambo, in your meter, or some other component that is more expensive to replace. The resistance should be ~1.1 ohms I believe. if it's far from this in either direction, replace the bed. If the wires fail continuity, remove them and test the removed lengths. If they fail, replace the wiring to the bed, and then retest (normally I'd say just replace it if it fails, but you said that there's damage to the solder pads.) If they pass, or the replaced wires fail, then replace the bed.

Inspect the power terminals and the fuse. Make sure the large fuse is seated properly, and that the connectors are free of melting or charring. If there's much corrosion, melting, or charring, send the board to Ulitmachine to be repaired.

Other things:
If the ambient temperature has changed much, then your max bed temp would go down.
check your temp readings against something more accurate. a thermocouple (maybe with the multimeter we just told you to get) would work well for this.
Make sure the thermistor is still properly potted, and not attempting to wriggle out.
What sort of solder have you been using? (Rosin core, Lead free, leaded, silver, or god forbid, pipe?)

[kevo3]

that almost sounds like more of a thermistor issue, if it's immediate. If it takes a while, then it may be a PID issue, or a loose connection somewhere (such as between the power supply and the rambo, the auto fuse being poorly seated, or loose connectors to the bed, not just the solder connections.) In my opinion, as far as dealing with the chipping on the bed, if you can, get some Conformal coat, and spray the areas where copper is showing to insulate it.

Go ahead and try to get a reasonable multimeter, which can handle at least DC voltage, resistance, and continuity.

Another question. Are you using the older ATX power supply, and if so, is it original or a larger capacity one? If it's the original ATX supply, it may be the cause of the issue.

If the power supply voltage is OK, and gets to the bed unmolested, then it may be an issue elsewhere. Check for continuity between the pad on the bed and the rambo terminal for each wire. Then check the resistance of the bed itself. Disconnect power before doing this. If you don't, you may blow a fuse on the rambo, in your meter, or some other component that is more expensive to replace. The resistance should be ~1.1 ohms I believe. if it's far from this in either direction, replace the bed. If the wires fail continuity, remove them and test the removed lengths. If they fail, replace the wiring to the bed, and then retest (normally I'd say just replace it if it fails, but you said that there's damage to the solder pads.) If they pass, or the replaced wires fail, then replace the bed.

Inspect the power terminals and the fuse. Make sure the large fuse is seated properly, and that the connectors are free of melting or charring. If there's much corrosion, melting, or charring, send the board to Ulitmachine to be repaired.

Other things:
If the ambient temperature has changed much, then your max bed temp would go down.
check your temp readings against something more accurate. a thermocouple (maybe with the multimeter we just told you to get) would work well for this.
Make sure the thermistor is still properly potted, and not attempting to wriggle out.
What sort of solder have you been using? (Rosin core, Lead free, leaded, silver, or god forbid, pipe?)

Using the newest power supply, with the open terminals.
Ive retested it a few times and its now getting up to 90 and a bit higher with little difficulty, BUT it will occasional dip down into the seventies then right back up.
I happen to have some automotive fuses on hand, so if need be ill replace the one on the board, But i doubt this is the issue.
As as far as solder goes, the first time around, i was using some thinner lead free that for what ever reason, refused to stick to the pad, (thus the damage to the pad, as i stayed on that one for a good while.) but it still became a hack job. I went back with a solder wick, took it up and redid it with thicker silver bearing lead-free solder (bonded exceptional well BTW)..
as far as ambient temperature, the room has gotten a bit cold lately, so i brought in a heater and kept the printers personal corner warm.
I really cant give any details on the flow of electricity till i get a hold of a multi meter, so sorry about that, but im open to speculations till then.

[ccavanaugh]

Measure the voltage at the heat bed when it's first turned on. It could be a weak power supply. It's about the easiest failure mode to check before you start swapping parts.

i dont have anything on hand to test it with, but i can get something tomorrow probably. Any chance it could also be a PID issue? because after it drops down to 72, it goes right back up to 85.

Make sure HEATED_BED_PID_MAX is set to 255. This will limit the maximum energy that can be pushed to the bed. I learned this the hard way when I was first getting started.

[geneb]

You should also check the compression terminals on the rambo to make sure you've not burned them up.

g.

[Eaglezsoar]

I wish that one of the requirements for buying a 3D printer is that the buyer also has a Volt Ohmeter to test voltage and continuity.
They are the handiest piece of electronics that anyone with a printer and other electronics devices can have.
They can be found for less than $10 on the net or at Harbor Freight. The second most important is a soldering iron with rosin core flux solder and
the third probably would be a meter that can accept a thermocouple to measure temperature. The laser type of temperature measurement is extremely
inaccurate when measuring reflective surfaces like the hotend and the glass on a heat bed.
There are Meters that incorporate the VOM and the thermocouple together as listed here: http://www.amazon.com/Extech-MN35-Digit ... uple+meter

[Windshadow]

Eaglezsoar.... good point.

I think its when you see printer kits being sold to folks that are not already a part of the maker movement (or just old tinker types like myself that could go to the boxes and find a temperature control antique soldering iron from my Heathkit youth) so they don't have the basic gear that folks that have been in the reprap world have been working with before making the jump to a 3d printer build project, that this problem shows up. and as 3d printing become more mainstream it might make sense to offer these items as add ons to the kits you sell.
In fact it might even make sense to sell them at cost when ordered at the same time as the printer kit.

[kevo3]

Measure the voltage at the heat bed when it's first turned on. It could be a weak power supply. It's about the easiest failure mode to check before you start swapping parts.

i dont have anything on hand to test it with, but i can get something tomorrow probably. Any chance it could also be a PID issue? because after it drops down to 72, it goes right back up to 85.

Make sure HEATED_BED_PID_MAX is set to 255. This will limit the maximum energy that can be pushed to the bed. I learned this the hard way when I was first getting started.

can i do this through the LCD? or only matter control in the eeprom settings?
Edit: checked it in matter control, Bed heat PID max was set to 200.changed it to 255 Gonna test it out now.

[kevo3]

Seems to be a tad bit more consistant. stil likes to drop to about 83 when its set for 90, but quickly brings itself back up.The Heated bed PID minumum is set to 80 i believe, should this be higher as well?

[ccavanaugh]

Seems to be a tad bit more consistant. stil likes to drop to about 83 when its set for 90, but quickly brings itself back up.The Heated bed PID minumum is set to 80 i believe, should this be higher as well?

I would leave the min alone. It will prevent you running at lower temperatures should you need to.

A heat spreader will help with the temperature drops a bit with the extra thermal mass. Have you verified your voltages?

[kevo3]

Seems to be a tad bit more consistent. stil likes to drop to about 83 when its set for 90, but quickly brings itself back up.The Heated bed PID minumum is set to 80 i believe, should this be higher as well?

I would leave the min alone. It will prevent you running at lower temperatures should you need to.

A heat spreader will help with the temperature drops a bit with the extra thermal mass. Have you verified your voltages?

Unfortunately for the voltages, i couldn't get the multi meter today. Ill have to find one in the very near future, as ive been needing one. Perhaps walmart? or would i be better off ordering one?

[barry99705]

Seems to be a tad bit more consistent. stil likes to drop to about 83 when its set for 90, but quickly brings itself back up.The Heated bed PID minumum is set to 80 i believe, should this be higher as well?

I would leave the min alone. It will prevent you running at lower temperatures should you need to.

A heat spreader will help with the temperature drops a bit with the extra thermal mass. Have you verified your voltages?

Unfortunately for the voltages, i couldn't get the multi meter today. Ill have to find one in the very near future, as ive been needing one. Perhaps walmart? or would i be better off ordering one?

Walmart would work. I'm pretty sure I got mine from Lowes or Home Depot, can't remember.

[Windshadow]

also any hardware store of even moderate size such as a tru-value affiliate ,a NAPA auto parts store, or a radio shack will have inexpensive multimeters

[kevo3]

I have tommorrow off of work, so i shall make a stop or two to pick one up, ive been looking for an excuse to get one any way.