Deep breath…
Hokay build seems to be fine, apart from-
X and Z will home, but Y moves in opposite direction, fan spins up ok, Printhead thermocuple works (will register body heat), heated bed shows 738.8/55 centigrade, extruder motor not working either!
Am banging my head here please advise
Hy, for Y axis maybe you invert cables.
I suggest you to verify all solders and cables first. If you think that all is ok, maybe you will have to send back the mother board for repair 
The heatbed temp signs out a short in the thermistor wiring. Check for that.
To correct the Y axis movement direction you an either swap the wires on the motor wiring, or reverse the direction in firmware.
Alrighty then!
The bed thermistor is kaput no 2 ways aboot it, I did a quick test with a heated ali plate, NO response, reads 30ish on the meter. Hotend however does register ali plate. Luckily I have a replacement due in the morning, lets hope that cures it!
Hmm, don’t want to be hacking the firmware just yet, I will have to look at a pinout on the connector and see if that works.
One step at a time! lets get this bed working first!
Unplug therm 2
The software should go to 0C
Check the resistance at the plug (not the board) for therm 2
Should read around 100K
New bed thermistor installed, unplugged (software zeros out) tested at aboot 100k on both of them to make sure, when plugged in and connected the bed still showing wayy off scale on the software!
Did the pinout on the motor last night now moves in the right direction, albeit a bit jerky, No not belt tension!
NOW what? am beginning to think either duff heatbed, wiring or (hopes not) control board/firmware??
Did you measure what resistance the bed thermistor gives at the plug?
If not, unplug it and measure across the plug contacs.
Can be there is a short in the wiring.
Update:
Tried a different approach: disconnect the bed completely, fire up the extruder- yup job’s a good one, it works (in as much that it heats correctly, but no activation of the extruder motor yet). Then all over the bed like a baad rash with the multi meter, first a bleep check for continuity, both circuits sounded out, then over to Mr Ohm he reads in the high 90’s all the way down the line to the control board for the thermistor, and a comparable amount on the heater to boot!
I’m suspecting that the controller may have a gremlin inside! T1/H1 works just fine so far… mebbe T2’s input is fritzed on the board…???
[quote=“wormster”]
I’m suspecting that the controller may have a gremlin inside! T1/H1 works just fine so far… mebbe T2’s input is fritzed on the board…???[/quote]
That would be simple to check. Just connect the Hotend thermistor to THERM2 (swap the plugs) and compare the readings.
been there… done that already!
Deffo the controller board!
What temp readings do you get on THERM2 when its not connected, and waht when it’s shorted?
Unplugged it reads zero/zero, when plugged in it reads 50/730 degrees.
Then the board is NOT dead.
Either the thermistor is dead or you have a short in the wiring.
HOW can I possibly have a short in the wiring WHEN going to CONTINUITY on my multi meter and testing T2 it bleeps (confirming the circuit is ok) AND when I measure the resistance of the thermistor I get a reading of 90+.
90+ Ohms or 90+ KOhms (kiloohms)?
90 Ohms is way too low.
The Thermistor should have around 100kOhms (100000 Ohms) at room temp.
I get a reading of 98+ when switched to the 200k setting in the ohm range.
Then The value is ok. But the 700+ °c reported by the board indicate a short. (you can verify this by shoting the THERM2 pins:
The reading should go from 0°C (open) to 700+°C (shorted). If so, the board should be ok.
Where did you measure?
On the thermistor itself or on the pins of the unplugged connector?
Measured at the thermistor, solder joint on the heatbed and at the molex connector.
Right I tried your trick of unplugging T2, and when I did the temperature dropped to 0/0, putting a crocodile clip in the prongs of T2’s terminal on the controller board it goes up to 50/730,
Strange.
Do you have continuity to ground or +5v on any of the Pins of the unplugged molex connector?
(the plug not the onboard pins)