Reference voltages needed for Tonepad's FV-1

[Stu]

Hi all,

I've had a FV-1 built with the exception of the 3.3 volt regulator (can't find them anywhere locally).

I figured that I should be able to get 2 LEDs and a resistor to give me 3.3V and after breadboarding it - I had what I thought was a voltage reg.

I hooked it up and the 3.3voltage dropped to 0.8V, I took off the 3.3v regulated voltage and even without any voltage apart from the main 9V and earth connected I have 0.49V on what I would expect would be an 0 voltage trace.

I think something's fishy with my voltages and was hoping someone would be kind enough to measure some voltages around the place to help me debug.

Currently I have:
On the FETs - G 2.29V (seems too low)
                     S 5.21V
                     D 9.00V
On the Input to the FV-1 0.99V (Could be a reason that I'm getting 0.49V - seems about half of the voltage on the input).

I'm worried that I fried the chip.

If anyone has any tips on how to figure out if my chips blown that would be handy too.

Cheers,
Stu

[peterv999]

Hi all,

I've had a FV-1 built with the exception of the 3.3 volt regulator (can't find them anywhere locally).

Exar spx1117m3-l-3-3(/tr)

-P-

[differo]

I could check my papers at home, but basically you'll have 1,65V (or close to it) on inputs, outputs, and voltage reference pins (for instance pin 3). The most important thing is to get crystal working. I'm still debugging my build, but I have a commercial pedal which uses this chip and I measured voltages for debug purposes. My build works but not all the time but when it works it sounds is gorgeous! I used lm 317 to regulate 3.3V but that too might be a problem. I've bought some 3.3 regulators but it would be nice to get this to work cause its more generic way (read:cheap).

[Stu]

That 1.65V sounds about right (bias to the middle for full voltage swing).

I'm just back from holidays, so I'll be looking over this a little more in the next couple of nights.

I still think I fried the chip, so I'll work with that assumption until I see otherwise.

Thanks for the replies! 

[Ice-9]

sorry i missed the post and repeated the same info,  REMOVED