Hi all!
Back in 2017 I got a DIY LCR Tester kit on the AY-AT layout (this one in particular:
https://www.aliexpress.com/item/32645279970.html) but only now got around to putting it together.. and it doesn't work. I need to mention that I'm new to electronic circuits in general, in the process of learning (hence the DIY kit instead of a fully built one).
I will preface that I tried searching this topic in particular, as well as went through the FAQs on github - but couldn't find a solution:
it only turns on the backlight of the LCD screen when I press the rotary encoder, and nothing else (backlight turns off when I release it). Led is also always off, never turns on.
I've tried powering it either at 9v directly on the pads, or 12v on the barrel connector (both from a bench power supply) - and I only see about 0.14A when the backlight turns on.
As suggested in the FAQ, I checked the soldering and re-heated / added solder where it didn't look perfect, then I checked all caps (in-circuit, using a cap meter - UT601 - and am getting values for all of them - so my assumption is they're functional, albeit maybe a bit off).
I checked all resistors before installing, and other than a 5.1K one being around 4.96K, most were very close to their rated values.
When I press the rotary encoder, I get 5v on the LCD pins, nothing otherwise.
At this point, I'm not sure what to check - any suggestions?
I'm attaching a pic of the board layout (for reference, since the components are only identified by their values), and one of my built one (maybe you notice something off?)
Thank you in advance for any pointers!