I need a little help

[bluvet79]

I need a little help Please

I purchased a Velleman K2625 tachometer kit. I assembled the kit as per the diagrams. I misread the part about powering up the unit for test and setting. I powered the unit with 9 volt AC and pop-ed the voltage regulator in the circuit. I replaced the regulator and then powered the unit with 9 volt DC. The unit powered up. I then applied the 9 volt DC to the in or signal port. The tach would not convey a tach reading. I slept on it last night and realized I needed the DC for the + to power the board and the AC for the in or signal to the tach. I connected everything this morning and it works except when I adjust the RV2 Trimmer to set the tach at 7200 it will only go to 3200. Can someone please take a look at this diagram and see what I am missing or what I have done wrong. I have racked my brain and I am at a loss. I need a little help.

This is the weblink and pdf is the complete instructions diagrams and all.
http://www.velleman.be/ot/en/product/view/?id=9060

Thanks;
bluvet79

 

[JimB]

Check the resistors R8 and R9 and capacitor C10.
Make sure you have the correct values, that is the most obvious thing I can suggest to try first.

JimB

 

[bluvet79]

Thanks for the advice but I found the problem The Trimmer at RV2 Had to be changed from a 47k-ohm to a 200k-ohm. It works like a charm now.