The question was presented by Mr. Kenndy and was solved through the following email discussion:
I am writing you from Sweden and have some problem with timer for my ordinary coffeemaker.
The problem is when i´ve wired it all up and start the machine it works fine all time to the time elapse after about 35min, but if i will start it again 1 hour later then it not works nothing happens, seems that circuit is locked up or something.
I have sent you my schema that i use and may be you can please look at it and perhaps have some solution.
My circuit uses the coffeemakers on/off switch.
Looking forward to your answer
The circuit is unable to break the latch created by the diode connected between its pin#11 and the output pin#13. The circuit will need to be reset.
For this you will need to switch OFF power completely and wait for sometime and
then switch ON to restart the unit.
Alternatively you can add a momentary push-switch between positive line
and pin#12 of the IC, pressing this momentarily will reset the IC and
enable it to restart normally.
Thanks for your answer.
Even if i switch of power and disconnect from the mains so after 2 hours
it dont work. But a pushswitch between pin 16 and pin 12 do the job
but this little circuit is built in to coffemachine so i can´t use that
Is there any way to fix this in electronical way.
Iám looking forward for your answer and thanks once again.
Kendy, it could be happening due to the charge in the filter capacitor...try
adding a 2k2 or 4k7 resistor between pin#16 and pin#8 of the IC, this
should solve the issue.
A resistor between pin 16 and pin 8 (2.2K) solved the issue.
Thanks for taking your time to help me, I am very grateful.