Oh...yes guess I thought that went without saying....there is a 0.1uF cap a= cross the power pins. ----- Original Message ----- From: "davidcou@aol.com" To: Microcontroller discussion list - Public. Cc:=20 Sent: Wednesday, May 1, 2013 3:10 PM Subject: Re: [EE] Simple things in life...that don't work Try adding a .1uf on the power pins of the 'HC74. And for sanity check, you= could try putting a 10 Ohm resistor in series with the Vdd pin of the 'HC7= 4 then caps directly across Vdd and Vss of the chip.=20 Just 2 cents.=20 David Sent on the Sprint=AE Now Network from my BlackBerry=AE -----Original Message----- From: alan smith Sender: piclist-bounces@mit.edu Date: Wed, 1 May 2013 13:57:11=20 To: Microcontroller discussion list - Public. Reply-To: "Microcontroller discussion list - Public." Subject: [EE] Simple things in life...that don't work I'm feeling quite like an idiot..because this should be obvious...and so si= mple...its EE101 stuff =A0 74HC74 dual D flip flop =A0 clear and preset tied high (5V) thru a resistor (10K) =A0 D connected to !Q =A0 clock driven by a 555 timer as a one shot from an external trigger =A0 Q drives into another circuit =A0 Customer does NOT want a programmable part.... =A0 So the 555 generates the active high pulse just fine =A0 The D ff doesnt behave.=A0 The Q ouput just follows the length of the clock= pulse.=A0=A0=A0 It should toggle states on each rising edge of the 555 oup= ut.=A0 Q out is low,!Q is high,=A0clock comes in....D goes hi...but goes ba= ck low when the clock pulse goes away. =A0 grrrrrrrr....... --=20 http://www.piclist.com/techref/piclistPIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclistPIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist =20 --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .