Fuzzstortion – Bypass OK, No sound when engaged and touching metal? (Elec.Dummy)

[Anonymous]

First off, I am electronics illiterate. I can barely use a multimeter. I do not know what the difference between a farad and a nanofarad is, and I don’t know what a volt is.
Second, I have built six pedals, and all of them work (I somehow managed to bias the parts in two of them). They are all significantly more complicated than this kit.
Third, I am colorblind, and determining components by color alone is practically impossible for me. My wife has to help me sort when kits from other companies come in. HAHA.

For the life of me, I can’t figure out what’s going on with my Fuzzstortion build. I have double checked the wiring, remelted all the solder points, and still I can’t get sound when the effect is engaged (but I do get sound in bypass).

When the power is engaged, the LED lights up. If I touch the input cable with one finger (and raise my other hand in the air), the effect seems to work–I hear buzzing, and the volume and gain knobs impact the buzzing. But if I touch the metal of the enclosure, the jack sleeve, or the metal of the input jack, the audio completely cuts out. When plugged into a guitar, bypass works great, but engaged there is only buzzing, and a little popping when i touch and untouch metal on the guitar. I thought maybe my ground connection was faulty, but I have it hooked up all over the build (I’m pretty sure…).

Any ideas what the heck is going on? Here’s a gutshot. This is driving me nuts! Your help is greatly appreciated.

[Billy]

Can you post a pic of the DC jack so we can see the connections to it

What are you using to power it and which transistors are you using

 

[Anonymous]

Thanks for the the reply.

The transistors are labeled PF5102 and MPSA13.

I’m using a 9v wall wart that works with all of my other pedals. It puts out a little noise, but it has worked fine for testing.

I took some more photos of the power jack, solder points, and PCBs.

Thanks for your help!

[Billy]

I should have said a pic of the front face of the DC jack so we can see which solder lugs your wires go to

Everything looks correct I can’t make out whether your power wire goes to the middle battery lug or top lug

Edited

[Anonymous]

I’ve done that before and checked this time…it looks like the wrong lug in the pictures, but it’s the correct lug.

Do you think it could be one of the components? If it is, how do I check?

[Billy]

All component values and orientation that I can see look correct, does it do the same out of the enclosure

It does sound like a power fault hence the questions

Do you have a multimeter if so check what voltage you get on the main pcb ground and +9v pads

Some of your solder joints look as if they lack solder

Add a touch more, heat the pad and component pin for around 4 seconds and add a little solder you want a nice shiny adhesion between pad and component

[Anonymous]

Ok, will do. I’ll probably get around to it tonight. Thanks again for your help on this.

[Billy]

These ones stand out you can see some look dry and don’t appear to have good solder adhesion between component and pad

I’d also reflow any ball like joints they may be dry inside as I say just reflow for around 4 seconds with your iron set to around 370°C

[Anonymous]

VICTORY! It works!

I redid each solder joint. I also moved the 9v power wire to another pad on the PCB. After I did this, I measured the voltage at the transistors, and it was SIGNIFICANTLY higher than it was before.

Now that I’m thinking about it, I wonder if I stripped some of the stranded wire away with the insulation on my first go? I have never done that before, but I did notice a weak connection at my initial 9v pad.

 

Anyways, thanks so much for your help. I leaned a lot today (for example, I never knew about counting to 4 when soldering).

[Billy]

9 times out of 10 you’ll usually find when you get wierd goings on, crackles and hums it’s a power problem either dodgy ground, poor connection or inverted power connections, centre positive DC jack or power supply

If you check voltage to the main pcb power pads and get either 0v or – 9v etc, a minus or anything but +9v tells you it’s inverted or yuv got poor solder joints etc

Any troubleshooting is a process of elimination first thing you should do is visually check all component values and orientation, check solder joints for potential dry joints or bridges, then as you’d done check all offboard  wiring connections

If you got 0v you’d simply check all your solder joints have good connections and trace it back to where power comes from in this case from +9v, D1 cathode through R6 to VA then up to all your VA points you can see on the schematic, which should all be around the same

You’re always learning and the more you do it you’ll begin to recognise symptoms eg what mis biased transistors and ICs sound like and so on

Glad you got it going

[Author]

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