dtmf decoder 8870 not working

[Dalvir]

i used 8870 i connect the hand free to 8870 i press key it not generate any out put
i check crystal frequency it is 2.9MHz
so i replace the crystal
but problem still remain
then i replace both capacitor of 33pf & crystal
but problem sill remain i change ic 8870 with a ic 8870 which work in other circuit
but the problem still remain



i change the resistance b/w pin 2 &3 100k by 4.7k

 

[betwixt]

Change the resitor back to 100K or the input gain will be very low. How are you measuring the crystal frequency? Where is the 33pF capacitor connected?

Brian.