I bought one of these from Amazon. And when I could not get it to apparently power up I returned it and got a replacement. Same thing. So assuming this is actually a good device, any suggestions? They are nifty enough I may buy a second one just to turn it into a full time frequency counter.

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at just over $20 the price cannot be beat if they work that is.

 

hi W,
This link has a number of 'fixing' video's for this module, it may help.
E
https://www.youtube.com/results?search_query=Model:PLJ-8LED-H

 

Thanks, I had the wrong cable on the power supply. I would have never figured that out by myself. Looks like it's going to be a fairly usable module.

 

By the way, if you're looking to get some more you can usually find them on eBay and AliExpress for under $10. Such as this one: https://www.aliexpress.com/item/3256803117820058.html

 

Amazon is usually not the cheapest, but they are almost always the fastest. Not to mention their easy return policy. I am in the process of designing a 3D printed box to make a simple frequency counter out of it. It will probably use a 9 Volt battery ( rechargeable lithium). The one thing I got from those YouTube videos is it this thing is a major current hog.