I recently assembled an MK-160 kit (the latest of many I have assembled) and accidently applied reverse polarity to the DC input. Now it acts as if it is on all the time (LED illuminated) and I assume the malfunction resulted from the reversed polarity. If so, how can I repair the damage?
Please check the diagram: The circuit is protected agains wrong polarity with diode D1.
The problem must have a different cause. Check your assembly.
Make sure the problem is not caused by the 741 op-amp as indicated in this post:http://forum.velleman.eu/viewtopic.php?f=7&t=4735