555 timer causing my counter to start at 20 seconds

[psurob600]

I'm building a timer and it works perfectly using a signal generator for the clock pulse but when I added a 555 timer to it the counter always starts at 20 seconds. I am trying to attach the schematic but for some reason it wont attach.

[psurob600]

I am trying to attach the appropriate files.

[AGJ_CR]

Maybe the 555 is generating unexpected pulses at the beginning which causes the timer to jump ahead. You could use a simple switch to enable the output of the 555 after a while when we know it’s stable.

Check the attached file as a reference.

Regards,

AGJ

[aa232004]

hello guys.

I have it opened in MS14.

It works OK and begins to count almost immediately - the first pulse is little longer than other but not for much.

take a look at the attached picture -

it seems to me the problem is with PC system and not with schematic.

with hope it helps

thanks a lot

Michael