I have built M188, output LED indicates all is working OK but output relay is not switching. Transistor has 1.7V on base, ~12v on Collector and 0v on Emmitter, Relay tested OK, Relay diode checked OK, transistor replaced (from 2nd kit bought at same time). Supply volts adjusted within range.
Beginner at this, any ideas? Have multimeter and variable power supply
It would be best if you could some Very Clear and Sharp pictures of the top and bottom of the kit?
You will need to post the picture on a free website and post the links here.
Maybe some might spot the error.
I reasoned it out myself - transistor connected wrong way around. Incorrectly assumed label writing would be visible when installed, not tight up against relay. Missed thick guide line on PCB. Drawing 13 could be improved. Works fine now. Thank you.