Hi,
We have completed an MK129 Crawling Microbug and are having problems with the motors. One operates all the time whilst the other pulses occasionally. Adjusting the speed and sensitivity does not make much difference. Can you help? I have taken a couple of pictures as suggested elsewhere on the forum and posted them on Flickr.
flickr.com/photos/130870426 … otostream/
and
Make sure T7 and T8 are part number BC557
T7 and T8 are both BC557
Make sure potmeters have correct values.
Set SW2 to ‘straight’, set both sens. potmeter to same position, make sure both LDR’s receive equal amount of light, next check behaviour and compare voltage at different points in motor driver circuits. This will allow you to spot an assembly problem or defective transistor.