<p>I've just built my son's A6 and have connected all cables apart from the last power cables. The mainboard says hotbed line and extruder line but the cable says heatbed.</p>

<p>The cables are two red which are crimped together and two black crimped together.</p>

<p>All of the videos online show a different mainboard and connections.
There are more connections than cables because the wires are crimped.</p>

<p>I can't get my head around which wires go where, any ideas?</p>

The manual appears to be available here,
Installation Instruction_Anet A6 3D Printer - Elektor
However, according to
this comment
from
Hard copy of the build guide?
, there is a mistake in the PDF of the manual, with respect to the heatbed, and as such, it is better to follow the videos:
I find it is better to use the 3 videos:
3D Printer Instruction--Anet 3D Printer A6 Assembly Video 1
3D Printer Instruction--Anet 3D Printer A6 Assembly Video 2
Printer Instruction- A6 - Hot Bed Level Adjustment and Print Test
Only errors in the videos and i believe the instuction the Hetbed
fixing plate i have build diffrently , rotated by 180 degrees
vertical, since it is better for the belt and somewhere in the video
during fixating of the end-switch and the blower he interchanged the
screws.
However, looking at the manual, if it is to be believed, then be aware that
as well as
one connection for the extruder motor, there are two connectors
each
for
both
the extruder and the hotbed heaters:
One for the separate heating elements, of the extruder and hotbed respectively, and;
One for the thermistor sensor (both the extruder
and
the hotbed have separate thermistors).
This makes
five in total
for the extruder and the hotbed combined.
However, the power connections for the Extruder
motor
has four pins (in white at the top), whereas the heating elements for the hotbed and the extruder have two pins and are of a different shape (in green on the left). The sensor connections for both the extruder and the sensor have three pins (in white at the bottom), but it should be easy not to confuse them, so long as you follow the wires to check to which component they go to.
Additional points to be aware of
From
this comment
in the same thread:
I just built an A6 three weeks ago and with the videos it is really a
breeze to assemble the unit.
Just pay attention to the heat bed mounting plate as it is installed
bottoms up in the video. The bar connecting the outer two plates where
the heat bed is finally mounted should be below the plates, not above
as in the video.
Also, if you still have time, order some decent toothed belt, Igus
Drylin RJ4JP-01, and toothwheels for the Y and X belts and replace the
original pulleys, bearings, and belts before you even assemble the
unit. I just changed mine last week and it does make a hell of a
difference - with this little upgrades (cost me less than 30$ for
everything - at Amazon) you upgrade from an okay printer to a really
decent machine.
The belt:
https://www.amazon.com/Anycubic-Meters-Timing-Pulleys-Printer/dp/B0152ZNDLK
The pulleys:
https://www.amazon.com/Aluminum-Bearing-Timing-3D-printers/dp/B0188HW4Z0
The bearings:
https://www.amazon.com/Printer-Solid-Polymer-LM8UU-Bearing/dp/B06XPRCMJS
(actually, you need 8 pieces - not seven as in the images - 4 for the
Y-axis and 4 for the X-axis)
The above are not the actual articles I've bought because I am from
Europe where Amazon sells in different quantities.
If you want to go on the safe side, grab a second power supply and two
MOSFET boards to remove the high current from the mainboard:
PSU:
https://www.amazon.com/eTopxizu-Universal-Regulated-Switching-Computer/dp/B00D7CWSCG
(just as an example)
MOSFET:
https://www.amazon.com/Wangdd22-Printer-Expansion-Heatbed-Current/dp/B01MY50JL3
Power socket and switch:
https://www.amazon.com/URBEST-Module-Switch-Certification-Socket/dp/B00ME5YAPK
Last recommendation: get some 3mm borosilicate glass to lay (clip)
over the heatbed. This will make the prints stick better and also
provide a perfectly flat surface for the builds (still, you'll need to
do the levelling)
Glass:
https://www.amazon.com/Signstek-Printer-Tempered-Borosilicate-2132003mm/dp/B00QQ5Q3BI
When assembling the heatbed mount, pay lots of attention to the 16
screws. Tighten them one by one diagonally and move the bed around. If
the bed feels stuck, loosen the last screws and shift the mounts
around a bit. The lighter this mount moves, the better your prints
will be.
One thing that you must be aware: This printer is a great little unit,
but it needs love, dedication and plenty upgrades. Out of the box it
works okay, but with the upgrades it becomes a really good unit.