Hi, I purchased three of these kits. First kit is built,boxed, fitted to car & working well. Kit number two is built,worked for short time on test,then stopped. Kit number three is built & working fine on test. Using kit 3 to obtain voltage measurements it is noticed that pin 3 on kit 2 is staying at 13volts(my test voltage) at all times & not dropping voltage to allow relays to operate. I have replaced 555 timer & C3 elect cap. LED stays on but nothing else happens. All resistors,capacitors & diode appear correct & all solder connections checked.
Help please for further checks. Thank you JohnDale.
Hello,
Have you checked D1 for proper polarity?
Hi, Yes d1 diode is correct. All three kits built exactly the same. I have even remade all connections on PCB in case I had a dry joint. The only thing I can’t check is the multi pole rotary switch. Both relay coil connections stay at test voltage +ve while on the working kits one connection goes -ve to operate coil. An interesting puzzle.Thanks for your interest. JohnDale.
Hi, Having now had time to study the circuit diagram I see the problem had to be caused by the diode D1. Having previously replaced the original diode with one from a packet of 25 I did not recheck it. I now find it is a faulty diode. Diode replaced again-kit now works fine.
Moral-just because a component is new doesn’t mean it’s OK. 