Geeetech

1. My original gt2560 had a blown driver for unknown reasons. I replaced it and I installed the new one for the 2 extruder stepper. But the problem is that the head fan with PWM is not working. So I decided to buy a replacement from GEEEtech since I could not see any external or visible damage to the boerd. So I assumed the damage might be internal to the Atmel mega2560 Chip. Perhaps a damage resistor or the AP2302GN(Look at gt2560 sch .pdf from another post). No visible damage can be seen.

2 This is very disappointing since I thought I was getting a new board from GEEEtech. I mean REALLY dissapointing!!!!. take a look at that capacitor?? bridging a Diode?? to another capacitor?? near top of the induction coil. What??? The thing is that I bought the board a few months ago and didn't realized until issue 3 and 4 came along. Can I have it replaced? is this what is causing the other issues????

3 After a few very busy months I got to start fine tuning and setting up the new board. After just heatting up extruders and bed for a little while: power just went off on the board. My nuts just went to my throat and it was hard to swallow them back. I started trouble shooting and it came out to be the 5A fuse was blown. Lucky I had a good one on the original box. If not gum wrapper would have to do for a while since this fuses are hard to find locally.
Replace the fuse. Now the LCD would have different contrast With or without the printer on. In other words, the text on the screen is barely visible on USB power and constrast would be to high under printer PSU power.
I have to add that the original board and the new board use to have the LCD contrast level the same.

4 after the Fuse Issue the temperature reading and the temperature set on repetier hover over the set temperature about 15-20 degrees higher and it cools down to about 5-10 degrees still higher that the set temperature. either just setting the temp on repetier or directly on the printer dialog with the usb cable disconnected. After a little while I get a Maxtemp error. Sometimes the reading jups several degrees up and then down. This has me completely dumbfounded. I don't know if this is a firmware issue or hardware Issue. I reupload the firmware several times and the problem gets fixed once the it starts doing it again even tho I completely reset the system... I mean I ever rest my computer.
5 Extruder 2 tip is about 1mm higher that Ext1 tip. Replace ext holder and is the same. I tried correcting the original base and It broke (layer separation) Obviously printed one before attempting to force it to level. bed is level and X axis rods are level to the 0.02mm using the Z stepper motor brackets as guide with a China mater electronic caliper from Harbor freight. At the current state my printer is working as a single extruded one with dead weight on the head. Really... I'm starting to think I should just convert it back to a simgle head printer. provided I can print a new base for it.

Well... What I would like to achieve is:
1 can I get a replacement GT2560. Even though I purchase the board several months ago. Yeah there is the issue of honesty. What can I say?
2 I whould like to know GEEEtech is aware repair (refurbished) parts are being sold as new. Did I mention "I'm so disappointed"
3 can someone help me with ideas what could be wrong with the original board and the PWM fan not working.
4 Whats the deal with the temperature going haywire. Firmware reflashed.... Is there a new version around. I have the one posted in this forum.

you can contact the seller to talk about the replacement.
The PWM fan will not turn on during the print untill you set it in the slic3r, so have you set it? and how's the connections of your fan?
the maxtemp error, you can refer to the link here:
http://www.geeetech.com/forum/viewtopic ... 13&t=17030

Hi. Thanks for approving and replying.

How do I contact Geeetech customer support? My new GT2560 is deffective but it worked fine until recently. I didn't see the component (repair???) until I had this issues last week. Is it under warranty from manufacturing defects???? I bought about 3-5 months ago. I have to check for Emails. I received the new board on or just before May 31. See topic when this happened : http://www.geeetech.com/forum/viewtopic ... 18&t=16371


I performed Max low temp test with jumpers. Low temp test indicated 0 on all sensors and Min temp error. When shorted Max temp warning appears and temperature fluctuates about 5 degrees randomly. from 340 to 344. ie. 341..344..341..343..344..etc every second or so...
When I heat ext1 and/or ext2 to 240 both temperatures go over and fluctuates Ie. 265 led light for the ext. heater turns off then goes down to 245 then turns on (blinking) goes up some 7-10 degrees. temperatures never goes under set temp. 245. After a little while or after a couples of layers printed the temp. goes up little by little. heater LED goes on and off like normal but after a while it goes to high and I get MAX TEMP error. I see Max temp on my firmware is 344. I did not change that. (i haven't modified firmware). Both temp fluctuates so I think both thermistors are working... or both are bad (not possible)

Is this firmware or hardware? I reflashed the firmware 3 times using Arduino ide 1.0.1 as instructed. Flash or upload was successful. I have not burned a new bootloader.

I see Max temp on my printer is 344. Both temp fluctuates so I think both thermistor are working... or both are bad (not possible)



On the original/old gt2560

Fan is connected correctly in pwn output and it doesn't work at all. tested printing and with manual control in repetier. There is no power so I tested resistors in circuit and they give me their correct ohm reading 10 and 4.7kohm. I don't know how to test the mosfed label 00B0 to see if it is working. I might buy some and replace it. Nothing looks burned. Board is clean. I have this issue explained in this post: http://www.geeetech.com/forum/viewtopic ... 18&t=16371

PS let me know if you need more info or test to do. Thanks

You can contact the sales in geetech official website and they will help you to solve this.
And for the MAX temp I think it is not reach to 344, it just reaches the temperature you set here: Maybe you can try to lower the temperature about 190-210 for PLA and 220-230 for ABS.

"tested printing and with manual control in repetier. There is no power so I tested resistors in circuit and they give me their correct ohm reading 10 and 4.7kohm. "
Could all the other fans working when you turn the power on? what't the voltage of all the fan sockets?
you can check the voltage of the pin16 as the picture shows. when you manually turn on the PWM fan on the repetier host, you'll get 5V between pin 1and pin2, and when tun it off, it's 0V.

No power to fan solved.

I fixed the original GT2560 that came with the printer. No power to fans including PWM fan. It was pretty straight forward in the logic. I just forgot that there was no power to all connectors and mistakenly thought the problem was only PWM fan conn making me asume the problem was between the connector all the way to pin 16 and maybe including the atmega2560 being damaged internally. So I replaced the diode on the board from one I got from and old IBM server blade. It took me quite a while to find one in the motherboard graveyard. So the Vin comes directly from fuse to diode then + pin on all fan connectors including PWM. Part id 1N5819. I think 1N5818 can also be used. There is a Vin VIA/Test point/power output that you can use to test to see if the diode is bad.