Wierd problem, Macheen

[LaceSensor]

HI,

I recently built up the Macheen PCB, today in fact.
I tested the circuit outside of boxing up, by connecting up with crocodile clips the in out 9v and ground.
Everything worked fine, so I proceeded to box up. Lo and behold, now boxed up there is an issue.
The effect passes clean fine, when engaged, its SUPER low output, even with every control dimed.
I can hear the fuzz effect, but its way way way too low, way lower than when I tested without the switching in place.

Ok you say, you effed up the switching.
Uh uh. I unsoldered everything, hooked the ins out and powers up like before, and same scenario.
Now the only issue I had when testing was before I soldered the power leads in to the power supply connect, I decided to test with the battery again (I use a battery snap and crocodile clips).
Somehow I managed to touch them together. This is the only issue I see.

I dont see how that will have damaged the effect, but I wanted to point it out. Ive tried to test briefly the other connections and all pots and everything feels secure.

I cant see it being a grounding issue either.


anyone experienced something similar?

HELP!

[bigmufffuzzwizz]

Do you have an audio probe? I never touch the BS170's for fear of frying them from ESD. I would use the probe to see if the signal drops around either of those trannys.

[k.rock!]

It actually sound a bit like a grounding issue...Probably not the jacks though, otherwise you would be getting a loud hum. Either way I'll ask, are you using metal jacks grounded to the enclosure?

Check your ground connections with your DMM using the continuity function. You might have something connecting to ground somehow either your board or some other contact.

If your grounds check out (and also parts that are not supposed to be grounded) then you may try Magic's suggestion of the audio probe which most definitely will point u to your problem.

Good luck!

-Kaleb

[LaceSensor]

Hi. Found the issue. Dodgy joint on one of the pots 

Sorry guys!
Thanks for the awesome suggestions though. I do have an audio probe, that was my next, along with posting the voltages.

I tried using some rainbow ribbon wire - never again! gonna try to rewire all the pots.
Whats the best way to desolder the double sided boards again?!

[mgwhit]

I made a component value error on a Fat Pants board last night -- somehow mistook a 47K for a 470R.  Once I found the problem, I used desoldering braid on the pads and leads.  After I got the majority of the surface solder off I heated the leads from the component side and used a solder sucker on the pad side.  Once it started to look clean I started prying at it very gently with a tiny flat-head screwdriver.  Few more applications of the soldering braid got it loose.

I was scared to death of desoldering -- you've seen some of the boards on here!  But this really wasn't as bad as I expected it to be.  Still a bit stressful, though.  And my board looks fine.  You'd have to be looking for the marks to see them.  Good luck!

[bigmufffuzzwizz]

Yes he's correct. Some situations a solder sucker can be used with ease but on a board I always use the de-solder wick now. It can be hard to get the solder to melt with the wick down so put a little bit of solder on your iron before to help the heat transfer and melt the solder underneath. When you get it down it should suck almost all the solder out in about 5-10 seconds without any damage to the board. Then exactly like mgwhit said with prying it out. Took a little practice but works a charm once you figure it out. Also flux will help with wetting the solder instantly.
I actually found the rainbow ribbon wire to be a blessing. My wiring for the pots at least has become so much neater and the stuff is incredibly flexible. Takes some patience to get them seperated and stripped/tinned but I prefer it now.

[LaceSensor]

I think the ribbon I have is cheap - the copper wire is simply 5 strands I think, and its not robust enough.