I had a short circuit by accident so the LM7805 blow up letting the 12 volt through. I changed the faulty LM7805 but the Steppers still don`t work so there is something else faulty. I still can connect to the board with printrun and read the heater temperature. One of the four pololu`s is getting very hot as soon as i connect the 12V. (dead i think) Another pololu does have 0,0V on the Vref (also dead i think) The two pololu`s left do have normal Vref and don`t get very hot. Is there a guide available how to test a pololu (by voltage or resistor value) and to test where on the sanguino (1.3a) the problem is ? mfg Chri https://reprap.org/forum/read.php?158,148142,148142#msg-148142 Mon, 16 Mar 2026 23:40:36 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?158,148142,148598#msg-148598 https://reprap.org/forum/read.php?158,148142,148598#msg-148598
Thinking about it, you should be able to use an oscilloscope to check that pulses are being produced by the chip and measure the enable pins on the stepper driver header.]]> yellow_fish Sanguino(lolu) Thu, 16 Aug 2012 17:53:58 -0400 https://reprap.org/forum/read.php?158,148142,148142#msg-148142 https://reprap.org/forum/read.php?158,148142,148142#msg-148142
I changed the faulty LM7805 but the Steppers still don`t work so there is something else faulty.

I still can connect to the board with printrun and read the heater temperature.

One of the four pololu`s is getting very hot as soon as i connect the 12V. (dead i think)
Another pololu does have 0,0V on the Vref (also dead i think)
The two pololu`s left do have normal Vref and don`t get very hot.

Is there a guide available how to test a pololu (by voltage or resistor value) and to test where on the sanguino (1.3a) the problem is ?

mfg Chri]]> Chri Sanguino(lolu) Tue, 14 Aug 2012 10:54:33 -0400