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Topic: mother board problem

I fixed the R271 with a dob of solder and a inline fuse. When it was altogether I started a demo print and the inline fuse I added blew...grrr ... have checked the repair plus the connector and can't find the problem. When I test the extruder heater plug off the board I get a beep from the multi meter so I have continuity there.
Once the MB is back in place the screen lights up as usual and then when the extruder goes to heat up the inline fuse blows again. I'm at my wits end and still can't find the problem. Any ideas anybody??
Pete

2 (edited by Tin Falcon 2016-08-30 10:19:34)

Re: mother board problem

you can not check a heater by checking continuity alone . the heater should have IIRC about 3.5 - 7  ohms. less than that and you likely have a short.
Sound like a short to me.

Tin

Soliddoodle 4 stock w glass bed------Folger Tech Prusa 2020 upgraded to and titan /aero extruder mirror bed
FT5 with titan/ E3D Aero------MP mini select w glass bed
MP Utimate maker pro-W bondtech extruder
Marlin/Repetier Host/ Slic3r and Cura

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Re: mother board problem

Thanks Tim I have a new one on the way so I'll wait and see what happens
Pete

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Re: mother board problem

You may want to take an ohm reading on the new one and record the reading for future reference.
most heaters are 20 watt or 7 ohm for 12 volts.
Tin

Soliddoodle 4 stock w glass bed------Folger Tech Prusa 2020 upgraded to and titan /aero extruder mirror bed
FT5 with titan/ E3D Aero------MP mini select w glass bed
MP Utimate maker pro-W bondtech extruder
Marlin/Repetier Host/ Slic3r and Cura

5 (edited by Pete49 2016-09-01 12:54:00)

Re: mother board problem

thanks. Will do. Just checked this one and it reads 5.2 ohms
Pete

6

Re: mother board problem

so per   ohms lawyou ar drawing just over 2 amps and  35 watts.
             http://www.ohmslawcalculator.com/ohms-law-calculator

sounds a Little high but not crazy  may want to look at wiring and the bed  as well.
sound like a short but do not think a 35 watt is an overdraw. remember amps can get a bit high  on a 12 volt system.
1 amp at 120 v = 10 amps at 12.

Crazy question but what size fuse did you put in you fuse could be the problem.

Soliddoodle 4 stock w glass bed------Folger Tech Prusa 2020 upgraded to and titan /aero extruder mirror bed
FT5 with titan/ E3D Aero------MP mini select w glass bed
MP Utimate maker pro-W bondtech extruder
Marlin/Repetier Host/ Slic3r and Cura

7 (edited by Pete49 2016-09-02 03:07:13)

Re: mother board problem

Its a 5 amp fuse as I couldn't get a 4 amp. I just checked my kit built printers hot end and its showing 1.5 ohms so the other unit is definitely higher. Being away from electronics shops I had to order it so will be here next week I hope. the bed works fine and continues to heat while the hot end blows the fuse.  I was thinking of trying the kit printer just to see if it will work. I guess failing that a new motherboard is on the cards. Oh BTW its 240v down here LOL but same rules apply
Pete

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Re: mother board problem

After some other events keeping me away from the printer I have now replaced the extruder heater and all is well in the world of the Da Vinci demon.  I now know why the link on the board crapped out smile Cheers for all the advice.
Pete