Im modding a 1/18th nylint rock crawler remote control vehicle. I did some wire re-arranging & everything worked.But I wasnt happy with the negative battery wire joint.So I re-worked it which it gave me some trouble. Why Im not sure.I guess the tip of the iron was dirty or I didnt use enough flux at first.I used a pencil tip iron (35w). There isnt any signs of burn marks on the board so Im thinking I just got it too hot and popped something on it somewhere. Im not that electronic savvy so I'd like to use this as a starting point to get to know a bit more on it. I messed around with the ohm meter & traced some lines on it. I tested the voltage on the battery itself & then plugged it in to the board (switched on) & went from there. Ive seen I get power down near(not on) the yellow wire which is the negative servo wire. The voltage there is the same as the battery. I did some other testing with the ohm meter near the red & white motor wires (to the right of them). The voltage there is near the battery voltage. When I touch ground and the red or white wires of the motors I get readings of .100-.245 for the front and .025 for the rear. I also did some continuity checks on some of the stuff. The motor wires are good after finding a broken + wire on the front motor in the axle. Again Im not that electronic savvy so Im just using common sense on how to do these checks. Its why Im posting too. Lol. The resistors on the board near the bottom of the picture is to slow the replaced servo down. I replaced the stock steering setup. Can anyone tell me the names of the parts I have the black arrows next to? And can anyone help me get this board running again? I would like to fix this. Just need to know the technical way of checking this out and finding what is exactly wrong with it. If you need a clearer image just ask. I had to shrink the size of it down a bit because of the host. Heres the picture
It looks like the arrow is pointing to a surface mount transistor.
As for the negative wire, you may have damaged the board. You should be using rosin core electronics grade solder, not solder in which you have to use an external flux. If you used acid core or used the wrong flux, you will be forming conductive bridges between the pads where the flux flows. Also the heat may have lifted the trace from the board.
Remote control truck board
Posted - Jul 26 2007 : 1:54:00 PM
