I just assembled the rolling message kit. Upon plugging it in to the 9-12 VDC power supply for a few seconds, the voltage regulator (VR1) TS78L05 gets very very hot. I unplugged the power supply for fear of a meltdown! I wasn’t able to get it working, aside from VR1 heating up.
I’m going to start troubleshooting, but I thought I’d check here first to see if anyone has any advice.
I’ve been using a 60 watt soldering station, so I question whether the heat could have possibly damaged a componenet (such as VR1)? This seems to be a relatively simple project, and all of the diodes, caps, etc. have been soldered in with the correct polarity. I’m not quite sure where I went wrong on this one. I’m thinking about replacing VR1-
Either you have inverted the regulator, or there is a short/low impedance at the secundary side of the regulator. Check your assembly. Watch for shorts, solder bridges, correct resistor values, diode direction, etc…
I removed the battery holder that screws into the solder side of the board, and one of the two wires connecting the battery had been crimped between the holder and the soldered leg of a component. It seems that this was causing a dead short. I put some heat shrink tubing around the damaged battery lead, carefully remounted the holder, and all is well
