Problems with Printrboard RevD

[RickRap]

I Just installed my new Printrboard and I am having some challenges. It is driving a QUBD TwoUp which is a simple Cartesian 3d printer. This printrboard replaces my my previous printrboard which was damaged when a spool of filament fell on it. Up to that point, my original board was working fine.

I installed the new board and uploaded the same firmware I used on my previous board.

Problem 1
As soon as I power up the board, the cooling fan turns on. It will not turn off using M107 command. However, once the machine moves in the z-axis, the fan will turn off. However, after 2-3 minutes the fan comes back on.

Problem 2
On my previous board, I had the stepper current tuned to 1.45v reference voltage on all my steppers. If I use that same setting on this board, my stepper motors skip or jam during a print. I can tune these down to about 1.2v, but then they seem to lose torque.

Is this something in firmware or is my board defective?

[zhangxueyou]

What is the version of your prvious board?

[RickRap]

This is my original printrboard:

WP_20150513_001 (Custom).jpg (196.83 KiB) Viewed 11385 times

This is the board I received from geeetech:

WP_20150513_001 (Custom).jpg (196.83 KiB) Viewed 11385 times

[RickRap]

apologies. those were the wrong images.

This is my previous board:

WP_20150513_002 (Custom).jpg (223.95 KiB) Viewed 11385 times

This is the board I received from geeetech:

WP_20150513_003 (Custom).jpg (220.17 KiB) Viewed 11385 times

[zhangxueyou]

Please check if this place is short circuit.

QQ截图20150514134613.png (685.34 KiB) Viewed 11382 times

[RickRap]

I tried to get a closeup picture but it's not clear. There does appear to be some issues around those pins. When I hold it at an angle I'm able to see a little under the pins and there may be some solder behind them that is shorting out the pins.

[zhangxueyou]

If you have multimeter, please check if that 2 pins are short circuit.

[RickRap]

of course. what was I thinking.

yes! I measured all pins on the chip. there appears to be a short across 4 pins directly behind the jumper that you identified. Some of the pins are reading 0, others are reading around 150k. All other pins have no readings. Following the traces I can see they lead to the fan.

[zhangxueyou]

Do you have needle or electric iron? If you have, please break where the short circuit is.

[RickRap]

or, how about you send me a new board that's not defective?