Fulltone Choralflange problem????

[AC30Dirty]

Hey guys, ok...i have a Fulltone Choralflange pedal that  busted on me. In bypass mode everything is fine but when I turn the pedal on it makes a loud hissing, crackling noise thats similar to an old vinyl record player but way worse. i tried various differnt power supplies and with a 9V and still nothing. I tried contacting Fulltone but the way they have thier email setup is a PAIN!!!!! So, I thought i would come here as an alternative to see what you guys thought. To me, it sounds like a bad IC Chip but, I wouldn't know how to tell which one. Any thoughts or suggestions? Thanx

[R.G.]

I think most of the chips in that thing are socketed. You might try removing and re-seating each socketed chip before you go too wild on fixing. Sometimes socket contacts get dirty. Be sure which way the chip goes back in before you pull it out.

[Mark Hammer]

I'm sure some folks are tired of hearing this from me, but I'm an evangelist for this stuff called "Stabilant" (www.stabilant.com).  It is a liquid that acts as a contact enhancer.  It forms a stable nonvolatile layer on the surface of contacts that you apply it to.  In the world of electrons, sometimes that teeny micron or two of space between a contact and a pin can make the difference, and Stabilant can fill in that gap nicely.  I have personally resurrected several effects by applying a tiny poppy-seed-sized droplet to each pin of an IC socket and then re-inserting the chip.  Of course one could remove the budget sockets and replace them with higher-priced machined-pin IC sockets, but there is clearly a risk of damage to the board, particularly if the board is double-sided.  In such instances, a dab or two of Stabilant is the wiser approach.  Doesn't hurt to maybe lightly scrape the IC pins a bit and restore some shine to them if some tarnish has accumulated.

[AC30Dirty]

Hmmm....that stabilant stuff sounds interesting. Plus, I had never heard of it!!! I'm definitely gonna take a look at the IC's and remove the ones I can an replace them; maybe it is a bad contact??? I opened up the pedal and everything looks perfect and I was pretty thorough in inspecting it. This may be kinda of a dumb question but, is there something I can use that could possibly tell me where exactly in the circuit, things start to go bad??? maybe that'll narrow down a solution. Thanx for the suggestions so far!!!

[Mark Hammer]

Well, from your first post, it would appear that there is NO audio signal when the effect is engaged.  That suggests that the "problem" is not confined to just the delay chip and its adjunct circuitry.  Since Mike Fuller makes a big deal about true bypass, we'll assume that any problems in the power supply which might affect the entire circuit would have no bearing in bypass mode.

So, probably the first place to start is with the power supply.  Do you have a meter for measuring voltages?

[AC30Dirty]

yeah I do. like i said in the first post, I've tried it with different power sources....voodoo lab pedal power 2, trex fuel tank, dunlop dc brick, the fulltone power supply that came with the pedal and a 9V battery and i get the same thing with all of them. I have measured the voltages being supplied by all those units and everything is good to go.  What else could I try???
 

[Mark Hammer]

I wasn't thinking about whether the power supplies could be delivered, but rather whether the "delivery was made"; i.e., are the chips themselves giving indication of being appropriately powered?

[AC30Dirty]

OOHHH....now i get it!!!! It's been a LONG WEEK!!!! From what I can see everything looks fine.... i can"t understand how the pedal can work at one point, then I reconfigure the whole board and now its not working. Plus I'm 100% sure I didn"t over or under power it when I reconfigured my pedalboard or even before that...