SOLVED Dielectric boost - no change when boost channel is engaged

[Jono SPR Pedals]

First pedal build, and it's been a learning experience. I've got to the stage where the pedal will engage, and sounds as I'd expect it to. The issue is when I engage the boost side which should be then controlled by the single pot. The sound doesn't change at all, and turning the pot makes no difference. The LED engages though.

I've tested the footswitches and they're OK, as is the cabling between the footswitch to the board. The connections to the power and jacks all seem to be correct when I use a multimeter. I think I've got all of the components the right way around, so I suspect it's a cold solder joint. I did this using a $10 soldering iron that I had bought years ago from the likes of an Aliexpress. I managed to pretty much melt that during this build, so I have decided to treat myself to a Hakko FX888d which should arrive in a few days. Happy early Father's Day to me. That should make the soldering a lot more reliable going forward. If I do have to resolder some components, it would help to know which ones to focus my attention on. Can anybody advise which ones to pay special attention to, I can't work out what the path would be once the boost switch is engaged. I'm assuming I've got the switch wired up correctly, I used multiple colours to help me differentiate which wire went where. There still aren't any build docs so I've based my build off some gutshots of other people who've successfully built a pedal using this PCB.



I don't come from an electronics background, just giving this a go as a hobby and to prevent me dropping obscene amounts of money on pedals again. Once I've got this thing working properly I'll post my trials and tribulations in the build forum. Any pointers would be appreciated

 

[Feral Feline]

I see you joined the forum two years ago, but this thread is your first post — sssooooo...

WELCOME! Even if you've been lurking, welcome welcome welcome.



You've noted yourself there's some reflowing to be done, but I'll chuck in 2¢ further to that thought.

One thing I noticed, is that a lot of your soldering doesn't seem to be penetrating.
For instance, on MichaelW's Dielectric Boost build, if you compare yours, MW's has solder reaching the pad and component lead on the components side — even though soldering on the non-component side, your PCB-pad and component lead should get hot enough to wick some solder through to the component side.

Check the #1 lug (upper left corner) of your "DPDT" switch, the blue wire — I can't even see any solder. Conversely, the bypass switch on the left shows a lot of solder on the lugs, big blobs of solder can mask the fact that it's still a cold solder joint. It might even beep on your DMM's continuity setting, but may not be making a solid continuous connection. I've had instances where I had a cold-solder joint, but the probing action of testing for continuity put enough pressure on the joint to close it up so it tested/beeped okay, but it was not.

All three of your pot's connections look bulbous and one or more legs might not have good continuity in the circuit.
Go for those perfect miniature Mt Vesuvius volcanic cones!

MW's gutshot from his build thread, linked to above — note the solder wick'd through and @MichaelW's perfect conical pot-soldering:

 

[Robert]

These are the components/points involved in the "boost" circuit.

Does your Gain pot have any effect at all when the boost is on or off?

 

[spi]

just giving this a go as a hobby and to prevent me dropping obscene amounts of money

 

[spi]

These connections look a bit suspect to me, especially the one on the right. There's some like that on your switch board too.
@Feral Feline's advice is solid.





Wait for your new soldering iron, it should give you better control of the heat.

 

[swelchy]

If he only knew… Son you gone learn

 

[Feral Feline]

Yeah, the rabbit hole may be deep, but it only leads to a larger burrow, that's then connected to the warren that's deeper and stretches further...

 

[Jono SPR Pedals]

Thank you all. It's alive, and sounds glorious. The culprits were a couple of cold solder joints. When the new soldering iron finally arrived it made a world of difference, I can even overlook its Ikea blue and yellow colour scheme. It did take me a while to get started, I've had the PCB sat in a drawer for ages. My wife says that if procrastination was an Olympic sport I'd be a 4 time gold medallist and considered the GOAT. So two years to get around to building it sounds about right. The rabbit hole is beckoning, working on the case design for the next one from the drawer of procrastination. Maybe I'll knock that one out in under two years.