Can anyone help with why the right hand relay is on once power is applied without pressing the trigger - I’ve managed to get it goi g for a Chap with a different board but this is bugging me -
Please help
I think the RH relay coil is as indicated by the red coil on pic. If so,
Check the blue dotted line track for any solder blobs shorting.
Check the devices at the end of the blue dotted lines (transistors).
As the relay is being energised when it should not be.
Thanks Mike for getting back to me , when I get back home later I will update a bit further , they is voltage coming out the little rectifier and down that blue line.
So - constant supply from the rectifier
As you can in the other pic they is a jumper and diode - I removed one side and relay didn’t come on - so went further back with it to the npn and that tests fine . Anything else you can see guys
How are you testing the transistors ?
Reason I ask is that they may show as good on a tester but leak when in circuit causing the false triggering of the relay.
Alsoi worth checking for shorts/bridging between some of the soleder pads (some look dodgy !
Hi Mike , I’ve tested them in the board and out the board - I’ve swapped the timer ic still the same - new voltage reg - still the same - the little npn are 92pu45a was trying to find a replacement and swap the two and be done with it , swapped caps too
Looking at this again correct me if Iam wrong please do , looking at the solder side - both npn are switching A relay on ? So if the other one is working ok then must be that ?
Well Mike you was right - they was breaking down once voltage was applied I owe you a pint bud - replaced both at first and both relays came on so checked data sheet and I had them back to front but the board for my own sanity is going again - but at least that Clarke has lived on and the owner is happy with his upgrade for free . Thanks again Mike