Gen 6 power problem
May 09, 2011 09:18AM
Everything been working fine, but when I just tried to power up the reprap, the power LED and debug LED just keep flashing. The power supply light is flashing too which is strange, so is this a power problem or a board problem?

When I plug the power supply in on its own, the light stays on all the time so bit worried the board is fried..

If it is the board, anyone know what happened and/or why? Is it reversible?!

(Ps. Using a regulated 12V, 5.0A DC power supply)
Re: Gen 6 power problem
May 09, 2011 10:22AM
Sounds like the regulators are brown-ing out and reseting continuously. Do you have an obvious short in your system somewhere? Trying unplugging all your connectors then powering it up and seeing if it still happens. Then plug each one back in turn (with the power-off) and see if it starts blinking again, that might indicate where the problem lies.

JB
Re: Gen 6 power problem
May 09, 2011 12:34PM
Thanks for the advice JB.

When I plugged them in separately it was only the heater that makes it flash! So problem found, now how to solve it? I'm wondering if it could be something to do with the wiring (although it all looks fine), or whether it is definitely something to do with the board (which leaves me pretty starnded). Any ideas?
Re: Gen 6 power problem
May 09, 2011 12:48PM
What type of hot-end do you have? Heater block? Or, nichrome wire-wound around nozzle?

Two quick tests I would suggest, unplug the heater. Measure the resistance across the heater terminals on the heater plug. It should be somewhere between 6 or 7 ohms.

Also, measure the resistance across the thermistor terminals. It should be around 180k-ohms (depending on thermistor and current temperature).

If either of them are zero, you have a dead short.

Also, check continuity between all the terminals on the heater plug and the extruder nozzle, just in case something has broken and shorted to the nozzle.

Depending on what has failed, it might have damaged your board, or it might be fine (the glass thermistor on mine broke while I was trying to fix the nozzle with it powered up - dumb! - and it sparked magnificently, but everything was fine).

If something has failed on your board, chances are it should be easy to replace. You can download the schematic for the Gen6 board on its wiki page and you can start probing around on the board if needed and see if anything is fried. All the part numbers are there, you can order replacements and solder them down if need be.

JB
Re: Gen 6 power problem
May 09, 2011 02:50PM
Thanks again.

It's a heater block by the way. I'm a bit of an electronics novice so.. presumably the board has to be plugged in and running to test all the bits you suggested using a voltmeter?
Re: Gen 6 power problem
May 09, 2011 03:21PM
Nope, nothing plugged in and certainly not on. You want a multi-meter set to resistance (not voltage) for this measurement.

The heater block has a 6-ohm resistor in it that heats up to warm the block, if you measure across the terminals with the multi-meter, you should measure the resistance of this resistor. If you don't see around 6-ohms, something is wrong.

The heater block should also have a thermistor in it. This is a resistor that varies its resistance based on its temperature. As it gets hotter the resistance decreases. It's used by the hardware to determine how hot the heater block is and switch off the heater. This should measure around 180-kilo-ohms at room temperature.

If your regulators are really browning out, it suggests that there is a short-circuit somewhere which is drawing more current than the supplies can deliver causing the power supply to shutdown (usually a safety feature). I suspect that the resistor in the heater block is shorting out, giving next to zero-ohms.

JB
Re: Gen 6 power problem
May 14, 2011 05:58AM
how many amps does gen6 require, 4 or 5 amps?
I'm planning on converting an AT or ATX power-supply to power my rep-rap Mendel

Edited 1 time(s). Last edit at 05/17/2011 09:21AM by frosticle.
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