StepSticks Prevent Electronics From Starting.

Hey everyone,
I’m having some problems with my electronics, basically when I connect a Stepstick to my gen 7 1.4.1 board running the Teacup firmware it won’t boot. When I remove them it starts fine and Printrun detects the printer. It’s kind of strange because everything else seems to work fine. Anyone got any ideas what the problem could be? Is it the Board, Stepsticks or Firmware? I don't know where to start.
Thanks in advance,
Leo.

Check that the stepstick doesn't have a short across the signal voltage pins.

The stepstick (like a pololu) has 2 voltage inputs:
Low (signal, marked VDD) voltage - usually 5V
High (motor, marked VMOT) voltage - usually 12V or 24V, depending on your electronics, power supply, etc.

Most electronics that use 5V to drive the stepstick/pololu will also use that to power the electronics (Gen7 does this). If this is shorted out, the electronics won't get power, so it won't boot.

Had a similar experience... move the jumper next to the atx24 to the other position so the atmega gets power from the 24 pin header.

Peter

What might be the reason for this? Is there some room for a better design?

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

No the 4 pin header was added to the PCB for use if you short out the green.black on the ATX - i.e. then the 4 pin molex is providing power ALWAYS

With the jumper in the other position, you're powering the ATmega from the ATX standby 5v line... therefore getting power even if the ATX is in standby. While in standby the molex pins dont provide any power.

I suspect original poster has it set to 4 pin molex. And not shorting his ATX to be always on....

In terms of design - no the flexibility is a nice feature - i've had PSUs that didnt provide more than 3.9v in standby - for them shorting our the green/black on the atx, and powering the atmega from the Molex saved the day!

I think its not very clearly documented to someone who hasnt studied the circuit.

Peter