- Joined
- Sep 22, 2018
- Messages
- 23
I have only found one thread on this topic. It was a long time ago and the OP has moved on to better tools. In case someone else has this issue...
Problem:
The motor would run nice and steady but the RPM readout would show a steady number for a while then it would flicker, numbers get dim, all 8's, 2's, then back to displaying. It was annoying to say the least.
Solution:
After poking around I found that the 5V power supply to the display board was bad. It was below 3V and fluctuating. I tracked the supply to the power board and U1 is a 78L05, 5V regulator. It was really hot. I found that the part was mounted backwards! I also saw some solder joints on the display and power boards that had flux on them. Typically manufacturers will clean their boards after assembly. I have a suspicion that the previous owner had this display problem and touched up solder joints hoping to find a cold joint. Not sure who installed the regulator incorrectly, manufacturer or the previous owner. I replaced U1 with a 7805, higher wattage.
Result:
Bob's your uncle. 5V is solid. Display is fixed.
Problem:
The motor would run nice and steady but the RPM readout would show a steady number for a while then it would flicker, numbers get dim, all 8's, 2's, then back to displaying. It was annoying to say the least.
Solution:
After poking around I found that the 5V power supply to the display board was bad. It was below 3V and fluctuating. I tracked the supply to the power board and U1 is a 78L05, 5V regulator. It was really hot. I found that the part was mounted backwards! I also saw some solder joints on the display and power boards that had flux on them. Typically manufacturers will clean their boards after assembly. I have a suspicion that the previous owner had this display problem and touched up solder joints hoping to find a cold joint. Not sure who installed the regulator incorrectly, manufacturer or the previous owner. I replaced U1 with a 7805, higher wattage.
Result:
Bob's your uncle. 5V is solid. Display is fixed.