MX2 Dollyshield - Motor 0 will go one direction but not the other. Motor 1 will go both ways. Solder issue?
Submitted by jabbin on Sat, 02/04/2012 - 17:44
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Hello. I have the Arduino Duemilanove using with the MX2 Dollyshield. I was just wondering if I mis-soldered something. My motor 0 (zero) will only go one direction and not the other (will go "L" but not "R"). Motor 1 (one) works fine and goes both ways. I'm thinking this is a mis-solder or something. Any idea what the problem is and how to fix it? I also tried to reload the firmware, but the problem is still there. Thanks for any help.
Jabbin, It's a rare
Jabbin,
It's a rare occurrence, but does sometimes happens - it can be related to the L293B driver, the 74HC00N NAND gate, or a bad 100k resistor - check those three for good solder joints and no jumpers. Especially check the pins called out in the solder instructions as needing extra heat due to the ground plane connectivity which acts as a heat sink. If all else fails, replacing the L293B and the 74HC00N usually resolves the issue.
!c