[Haberdasher 'Pepper Spray'] The 100uf cap keeps exploding!

[UHaveMySthapler]

I made a photo album of the before-and-after here: http://imgur.com/a/REw6B. I took pictures of the packaging for the 3 axial caps I used.

C1 is a ceramic 100pf cap, D4 & D5 are 1n4148's , and D1 & D2 are 1n34A's instead of 1n695's.

This is the THIRD time this has happened, and probably the quickest time it took to explode. The first time it was  a 100uf 35V cap, which allowed me to hear the pedal actually work, fuzz and all, for about three seconds, then BAM, the cap exploded. Tried it again with a 50V cap, still the same result. I meant to record this last test on video, but it exploded 2 seconds after I plugged in the power supply. The effect wasn't even on; it exploded just from being plugged in and bypassed!

I can check transistor values in the morning if that's necessary. Any help is appreciated! My Mudbunny build went without a hitch, I'm surprised something as simple as a Percolator is acting this crazy.

[DutchMF]

I'm not completely sure, but it looks like all your electrolythic caps are the wrong way round. The layout in the doc indicates where the '+' should go, and most caps have an indication for the '-' side. Check that orientation, might be an easy fix.

Paul

[Mike B.]

You have it in backwards. Electrolytic caps are polarized. The side with the stripe is negative while the other side (with the longer leg) is positive. The square pad on the PCB indicates the pos. side.

[Marv Mod]

Check your C3 and C4 too as they also look like they're in the wrong way round.


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[UHaveMySthapler]

Wow. I could've gone my entire life making pedals thinking that the striped side was the positive side. I knew the long leg on LED's was the positive one, but I guess I can't put 2 and 2 together when it comes to caps. 

I replaced the caps and put in new ones in the CORRECT orientation, and now it works, no explosions whatsoever! I flipped the 2n3565 around (flat side facing "north" in relation to the board) as well, because I couldn't get much fuzz with it oriented the way it was originally.

Now, is there a way I could allow it to have even more fuzz? It sounds nice as is, but I have to really crank the knobs to get the amount of gain I want. Changing the diodes in D4-D5, perhaps?

Also, anyone have any ideas what I could use my leftover 2n404A and 2n3565's for? I suppose I could just make another one of these percolators, but where's the fun in that?

[rullywowr]

I replaced the caps and put in new ones in the CORRECT orientation, and now it works, no explosions whatsoever!

Now with 100% less explosions!  Excellent job.   

The long lead on electro caps is still the positive side (like LEDs) but the stripe on the can assuredly points towards negative.  Glad you didn't lose an eye or something....BANG!
 

[GermanCdn]

Now that you have successfully blown up a few caps, the next fun surprise you're in for is one of the following:

1) Not putting the CLR on your indicator LED, quickly followed by a bright light, a fizzle, a pop, and some smoke if you're lucky or

2) Putting a dual opamp in backwards, then wondering where that burning smell is coming from and why you get no signal.



Welcome to the addiction.

[alanp]

I've done both of those, Curtis

Think of these things as learning experiences. It's like being told "don't touch the hot stove element", you're going to remember a LOT better if you actually do the mistake yourself 

[Guybrush]

The smell of burning IC's and transistors is so strange.

[pryde]

Forget "diode-destroyer"

He went straight for "electrolytic exploder" 

[billstein]

Only had that happen once. Totally freaked me out. If that thing had hit me in the eye I'd be one of those blind guys singing the blues right now. Blind Cappy Billie.