def 0/Bdef 0 Sudden Def...

[Gr8Scott]

I just can't win. I have put in the hours and busted my butt working on this machine for slightly more than a year now. Had to take a sabbatical from it for a while because I had thrown a lot of money and effort at this thing only to have it fall short time and time again. Now I am getting no readings on both thermistors when I turn on the Rambo. Checked both thermistors at the plugs going into the Rambo and both read 99/98K (room temp). This means that two of my ports are now dead right? Last night I was trying to dial in my first real print and I kept getting lockups where the machine just simply wouldn't continue on and essentially had to be reset and started over again only to fail again and stop printing a short time later. Is there a fuse for these sensors or am I just SOL on this? I have two available ports left that I can possibly reprogram the pins on Config H with, but it really stinks if I am down half my ports on the whole card as of now with no more spares and no room for future expandability.

Suggestions are most welcome at this stage. I'll take any help I can get.

[Polygonhell]

There to is no fuse on the thermistor pins, generally you destroy the input on the arduino when they go.

[Gr8Scott]

Found a thread that explains where the pin references are kept. [on a tab called 'pins.h'] Scrolled 90% of the way to the bottom of the page (or you can do a search for "Rambo Pin Assignments") and found the following segment.

Code: Select all

#define HEATER_BED_PIN 3
#define TEMP_BED_PIN   2 

#define HEATER_0_PIN   9
#define TEMP_0_PIN     0

#define HEATER_1_PIN   -1 //7
#define TEMP_1_PIN     1  

I revised this to say the following instead to make my two ports hopefully work again...

Code: Select all

#define HEATER_BED_PIN 3
#define TEMP_BED_PIN   3 

#define HEATER_0_PIN   9
#define TEMP_0_PIN     1

#define HEATER_1_PIN   -1 //7
#define TEMP_1_PIN      0  

We shall see how well this works later on once the wife passes out asleep and I can monkey with the printer without her claiming that I spend more time with the printer than with her. LOL I don't think she should be able to claim the time that she is sound asleep as "her time" as well.


_______________________________________________________________________________________


Edited to add that after checking to see how well this worked. It worked like a champ. Now the printer seems to be back on line and I can get back to making crappy looking prints with it. LOL


_______________________________________________________________________________________

Edited to add that I must have spoken too soon. Bed started heating up like nobody's business, but only showed 30 degrees regardless of how hot the bed got. Turns out the bed is now linked to the hot end thermistor (both are).

[Gr8Scott]

None of the other three ports are working now. Can I possibly solder on some new capacitors on (C3, C64 and C59) to get these ports working again?

[Polygonhell]

I doubt it's a failed capacitor, the most likely problem is a damaged ATMega chip, the analog inputs are extremely sensitive to over voltage, even slightly exceeding VREF will kill the port.
Worse the ports actually all use the same single ADC internally and with enough voltage you can kill that.

[Eric]

You made an oops. The thermistor ports are on analog pins 0, 1, 2, and 7. Not 3.

As for fixing blown ports, there are unused analog pins. Reassigning them to existing ports would involve cutting a trace and soldering a jumper wire for each one. I'd only advise that for people who understand what to do and are comfortable doing so.

Or you could add additional thermistor circuits/ports on an external board. The unused pins are all found on the "Analog-Ext" connector. You still need to understand what you're doing, but you don't have to modify your board, other than to add a header to the connector.

[Gr8Scott]

I have rewired the ouput section of a Peavey Butcher to take EL34 tubes and individually bias each tube using test points installed at the back of the amp. I'm comfortable with cutting traces and soldering in jumpers. LOL

Of course, that was on a much larger scale than these little beauties... I contacted Ultimachine and they are gonna fix it for me. I was startled by the level of customer service. I'm used to companies ringing their customers like cash registers, but these folks don't seem to be inclined that way and seem to genuinely want to help customers that have problems with their products. Just waiting on the shipping slip now and I should have my machine up and running again soon.

I will spend the downtime re-doing the notches on my X/Y/Z stepper motors to eliminate that problem for the foreseeable future. That really caused me problems as I did notch them, but didn't notch them very deeply. I assumed that the combination of a shallow notch and blue loctite would be good enough to prevent slippage. I'm REALLY going to put a serious flat spot on each and every stepper from this point forward to prevent that from happening again. I'll get a fresh container of blue loctite fluid (I used the gel last time) for the worm screws as well. That slippage on the Z axis was causing me untold misery all this time.