Re: Steppers not moving.
@magicmodel, It may be too late, but you have your cooldrvs mounted wrong way round. The pins marked A1,A2,B1,B2 should be closest to the motor connector.
View Articleheated bed and extruder not heating up
my heated bed and extruder refuse to heat up anymore they used to but don't now. i have a 12 volt 17 amp power supply but it doesn't work. any suggestions?
View ArticleRe: Steppers not moving.
Cheers bobc. I knew you would spot something obvious! I will go and try that now. Fingers crossed.
View ArticleLevel shifter issues
Hey all, Long story short, I'm working on a project connecting an LPCXpresso 1769 with my RAMPS, using some protoboard and a ton of wire. Since the LPCXpresso is a 3.3V board, I decided to use a level...
View ArticleRe: Level shifter issues
In case anyone's curious: just talked to the guys over at the Smoothie irc channel, and it turns out the problem is that the level shifter is the wrong component for the job, since MOSFETs draw such a...
View ArticleRe: Solving CPU overheating problem
My wiring on the printer is a little untypical. It is done with unusual thick wires and they are very close to (sometimes even attached to) the iron metal rods and I did twist them with each other. I...
View ArticleRe: Level shifter issues
Hi m8! The TXB and TXS level shifters are for logic, e.g. weak current. For example one of these cant even drive I2C coz of current limits. I suspect fet input gate capacitance may have something to...
View ArticleRe: Level shifter issues
Yeah, gate capacitance is an important but often overlooked characteristic. Everyone "knows" about gate voltage, but applying the right voltage is half the story. It is perhaps fortunate that we can...
View ArticleRe: Level shifter issues
Yup, changing a power mosfet with another power mosfet shouldnt matter much because the high capacitance is coming from the big physical geometry required to channel big currents, and that is more or...
View ArticleRe: Level shifter issues
For example looking at IRL3803 the total gate charge is 140nC and turn on is 14ns, so this is worse scenario than previous one, peak is now 10A. If its a mosfet driver with 1,5A, it needs a resistor...
View ArticleRe: Level shifter issues
Cool, thanks guys! Yeah, the gate drivers worked well on the XpressoSmoothie board, but some recent changes in Smoothie locked down the use of a bunch of pins to I2C and SPI, and unfortunately, they...
View ArticleRe: Level shifter issues
I think you could try running mosfets directly even at 3.3v. The problem isnt as much with mosfets themselves but more with the lack of current in the uC driving pin, which by being limited it then...
View ArticleRe: Level shifter issues
QuoteIf its a mosfet driver with 1,5A, it needs a resistor in line with gate to limit the peak current at 1,5A. Are you sure? I mean, currents are usually limited to avoid overheating. But if this...
View ArticleRe: Level shifter issues
If the mosfet driver has a rating of maximum 1.5A *peak* current and tries to charge a parasitic capacitance that tries to draw 10A peak current, that cant be good. It may work, but its not inside...
View ArticleRe: Level shifter issues
Ah just read it again and realized it was missing "peak" word under first number, as both are peak ratings. E.g. in the example 1,5A was peak rating of the mosfet driver, and 10A is peak current drawn...
View ArticleHeated Bed Safety Issues
Hi everyone, We are looking into putting together a 12" x 12" heated bed for our new printer and are probably going to go with a nichrome wire heated version. We are concerned about safety issues with...
View ArticleRepRap kit buying
I'm new to the forum so I apologize if this post is posted on the wrong folder. I nearly bought this "RepRap complete kit" from Amazon.com: Reprap complete kit Ramps1.4,LCD2004,heatbed...
View ArticleSome problem of electronics
Hello I'v constructed a RepRap Prusa Mendel for almost a month. And I've bought an R2C2 3D Printer controller for my 3D printer. I connected all the electronics include stepper motors , extruder, and...
View ArticleRe: RepRap kit buying
Your motors should have some markings on them, but sometimes its hard to identify coz there are lots of versions of exact same looking motor, sometimes even bipolar and unipolar look identical and...
View ArticleRe: Heated Bed Safety Issues
Yes I use resettable thermal fuses on my heated beds that use resistors. The PCB ones are self limiting because the resistance increases with temperature. The other issue is the wiring has to be...
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