ad3208 analog delay not working... help please!

[spacecowboy78]

About a month ago i built the ad3208 analog delay from general guitar gadgets but is not working. I saw people who already has built that one here so if you can help me i will appreciate it. I've been testing with the multimeter and the only mistake i found was that in the mn3205 there was 1.71V on pin 5 and 0.92v on pin 8 and the led is off. This only happens when i put those ICs on the PCB because if they are off the PCB i measured voltage in their sockets and there was 8.5V on pin 5 and 7.98V on pin 8 and the led is on. I'm not sure that's a mistake but in the datasheet shows supply voltage of 5V. I'm using a 9vdc 1200mA adapter.

Hope you can help me

[armdnrdy]

Good place to start:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[mcknib]

I'm not familiar with this build what are the MN3205 voltages supposed to be? because if they're supposed to be what you get with the IC out of socket that would suggest either a faulty IC or a possible bridge somewhere that only shorts /draws current when the IC gives it a path.

I had this recently with a TS build where I got weird voltages with the IC in socket and perfect voltages with it out of socket, I tried several other IC's with the same result and eventually went over the solder joints with a magnifier and noticed a very small solder bridge between 2 resistors, snipped it out and all was good.

Best to do what Armdnrdy suggests though - follow the troubleshoot guidelines and give us as much info as you can images of the front and back of the board, off board wiring and voltages etc if people can see it they may spot something you've overlooked like incorrect orientation, wrong values etc it's easy to overlook something when you're frustrated and it's a fairly complex circuit


I don't want to sound like a broken record but if you phone your mechanic and tell him your car's making a noise it's unlikely he'll diagnose it over the phone without seeing it! and we all know pictures speak a thousand words! and hopefully those that know a lot more than me ( and there's a lot of them) will spot your problem