Hello All

i have bought a megatronics v2 from ebay, i think its a sainsmart as most of them are (correct me if im wrong).

i had a problem with the endstops shutting the board down, i found a cure for that the connectors were labeled different then the original one.


but i still have the problem that i cannot use the board without the usb cable, if i remove the jumper that supposed to make it rely on 12V the board doesnt start. i found some topics related but not stating the same problem i have and how to fix it.
Next to that the fan controller doesnt work, not from repetier and also not if i send a gcode to start it. its not the fan i tested that and it works fine on a 12v line from i atx supply.

i would really like some help cause i cannot find a post from someone with the same problems

regards
Weedz

You popped the on-board 5V regulator when your mis-wired endstops triggered and caused a short. Whatever regulator Sainsmart used is hyper-sensitive from my experience. My fix was to power the board from USB and forget about the on-board power.....

aah nice :|
do you think it is replaceble? or can you wire it witouth being hooked up to the pc (like a phone charger or smt)


do you think that it could be related to the fan problem aswell

Edited 1 time(s). Last edit at 02/24/2015 07:14PM by Weedz.

Lmao I did this last night. The part you are looking for is "AS1117 5.0" Going to have to go back and do some probing before I connect the stops again.

my endstops are working fine now only the board only powers from usb.....

and my fan doesnt work, but i dont know if this is a boardmallfunction or something wrong with the pins or whatever

Same problem about LCD only work with USB power , any advise ?

IC2andFuse.bmpHello
This is the same problem mate forum samotras
and it was met with success
checks the route, 12v entry into the pin3 of IC2
path: power supply, fuse, diode jumper and pin3 ic2 in the back of the card
the output of the regulator is 5V ic2

I've managed several with the same problem,
the replacement regulator you can search the web for SOT223 5V regulator
Substitute small list of regulators
LM1117 5v
ams1117-5v Ams1117 1117 5v
Mic5207-5.0
ld1117s50tr / ncp1117st50t3g
ap1117e50g
   lm2937imp-5.0

The regulator is required 5V output does not work with 3.3V
Check the route in the image..

This is to repair the LCD volage without USB

regards
Bernard