Velleman K2579 Universal Start/Stop Timer Kit

Hello I recently bought a Velleman K2579 Universal Start/Stop Timer Kit. The kit works perfectly but their is only one thing i would like to change. I would like to have the time adjustable between 1-15 seconds and have those be the maximum and minimum i just want the timer to run for 8 seconds so i want some room to work with. Is it possible to put a smaller capacitor in the kit maybe around 33uF 16v or how small could i go with this kit without ruining it?

You can’t do much harm by lowering the value of the timer capacitor. Experiment.

Hello so i went to my local part store and they had a 10uF 35v I wanted to replace it with a 16v but all they had was 35v. I removed the IC before i switched capacitors and when i put the IC back in the kit worked just like i hoped…Kind of. The next time i pressed the start buton it was like the start button was the timer, I would press the start button and the light would go on and when i released the start button the light went off. This happened for quite some time then the timer worked as it should, then it went back to the start button problem. Is this because i put a higher voltage capacitor in the kit? I think 10uF is what i want but should i get one that is rated 16v and will that fix the reliability? Thank you

Voltage of the capacitor is not important as long as it’s higher than the real voltage that will be applied to it. So 16 Volts is enough but 35 Volts or even more is also no problem.
Intermittent problems are in most cases bad connections: didn’t you damage a pin of the IC or a contact of the IC socket? Did you remove the old solder before putting in the new capacitor? …

So that capacitor works? Alright well do not have any desoldering itmes around here i just heated the solder and pulled out the component and heated the solder back and put the new component in. The solder joints don’t look cold, but is there any way to fix this problem?

Sorry, can’t diagnose from a distance… Very high resolution and SHARP pictures (not from a phone) can help people here finding your problem.

I think I found my problem when I tried to put the IC back in pin 8 bent and was not always making contact I re put it in and all seems to be working fine the new capacitor works as well I might even go to a 4.7uF capacitor thanks do much for your help!

You’re welcome!


Please help!
I set potencio meter the 6 minutes to the maximum time :frowning:
How can I fix it for 30 minutes?


Could you post pictures of your kit?
It should reach the 30minutes.

Best Regards