K8086 problem


I’ve assembled my K8086 and as soon as I plug the 12V the relay is triggered, even without the phone line attached. Then when the phone line ring nothing more happen with the relay.

I’ve checked my assembling for reversed polarity components and everything is good and according to instructions.

Also, when I connect the phone line alone or with the 12V the LED lit a little bit, then it’s brighter when the phone line ring.

Please help me find the problem, I really need this device to work.

Thanks you!

Most likely an assembly problem.

Check for soldering problems and check R4, R3, T1, R5, C3
Make sure opto-coupler is correctly inserted.

I forgot to post my reply, I found my problem, it was indeed a soldering problem, I use a type of solder that have a resin that stay kind of greasy and I didn’t washed it. I then washed it and the unit began to behave correctly.

I have the same issue and have checked very carefully all soldering joints seem good. I have done soldering for over 40yrs… and while I need readers to se clearly up close… I think this all looks good… but I am not 100% sure of the IC directions, the Socket was clearly marked with a notch… but the IC only had a dot on one corner I assumed that was Pin1, I used Safety Wash and carefully cleaned and checked to ensure there is no cross over from one solder point to another…

Here are a few pics from before I cleaned the board today.