Help with DIY guitar pedal - Page 1
Forum section: electronics / projects

author: Scornn
author_rank: Contributor
timestamp: April 29, 2024, 11:56:02 am
content: Not having too much luck with this pedal I bought as a project. I am able to get power and bypass but no actual signal when its switched ON. I did take it to a shop to have it looked at and had a resistor replaced and things cleaned up a bit (thats what got the bypass working) but still not working as intended.This is the data sheet I followed:https://www.diyguitarpedals.com.au/shop/boms/LichKing Chorus.pdf

author: CaptDon
author_rank: Super Contributor
timestamp: April 29, 2024, 12:39:33 pm
content: Holy crap, soldered by a 6 year old? There isn't much to go wrong. Probably wrecked the I.C.'s? Clean up the piss poor soldering, snip off the excess leads of the through hole components and look for solder bridges between components. There may even be shorts under the I.C. sockets. What is with all the arms and gator clips holding parts like a deco art mobile in mid air?

author: moffy
author_rank: Super Contributor
timestamp: April 29, 2024, 01:29:39 pm
content: If I had that given to me, I would desolder everything and start again, if that was at all possible.

author: mag_therm
author_rank: Frequent Contributor
timestamp: April 29, 2024, 02:42:18 pm
content: I had a batch of those pressed wafer type of 1/4 mono jack.The solder tag can be open circuit I think due to poor press during manufacture.Intermittents there can be tricky to find , they work on bench test than fail while the musician is dragging the cable around .

author: Terry Bites
author_rank: Super Contributor
timestamp: April 29, 2024, 10:42:40 pm
content: What the flux mate! Did you kick off this project at beer o'clock?The pcb needs a good clean and a detailed inspection. I bet there are some dodgy joints and shorts around.Methodically check through all the wiring and component locations. If that fails, I'd say it's time for a rip up and retry.On the up side you socketed the ics. Rescue them and just junk all the passives and any other stuff you soldered in direct to the board.Use a solder pump and solder wick to remove all the affected parts, they're all dirt cheap and easy to find.Invest in a selection of hookup wire colours, it'll redcuce the brain ache.Bucket brigade delays are very noisy and very lo-fi, so 80's, hissssss.

author: Scornn
author_rank: Contributor
timestamp: April 30, 2024, 06:59:51 am
content: Okay so did I mention I was very new? So I've got mutilple coloured wires now, had the board cleaned, replaced the ICs and clipped the wires but no signal when on still

author: donlisms
author_rank: Frequent Contributor
timestamp: April 30, 2024, 10:46:08 am
content: I might put it this way, if I was trying to helpful, rather than... well, like those guys.Let's assume, to begin with, that the parts are okay. Maybe a bad assumption, but you gotta start somewhere. The other thing that's going to make the pedal work or not is how those parts are connected.I don't know your impression, but after doing it my whole life, my opinion is that good soldering is not an easy thing; it doesn't just happen. Any acquired skill deserves an investment - you learn and practice. You need to have a solid idea of what a good joint looks like, then how to get there. And it's good to do that as an exercise separate from your project, so you can make mistakes, as many as necessary, without doing harm. Once you have your skills lined up, you just do the project, and it's perfect.You're kinda beyond that point, I guess. But I would set it aside, learn and practice soldering until I could tell "those" guys how to do it, and then come back to the project. Watch a bunch of videos - some will be better than others. Practice. A lot. Most importantly - evaluate what's wrong, for yourself, and figure out (for yourself) how it went wrong, and what you're going to do to fix it. Practice enough that you can see trends, common problems you're encountering all the time. I just soldered several hundred SMD resistors, progressively smaller, because my SMD skills were marginal. Do 10, evaluate them, improve techniques, do 10 more. And again. It made a huge difference.I can't see the finer details in your pictures in this tiny phone screen, but I'm going to make a guess that you have some shorts, and/or possibly other connection problems. I see too much solder in various places, and you can suck that up with solder wick or other mechanisms. There are other potential issues.You're going to have to double check every connection. Not most of them, not the easy ones - all of them. You need to know every connection is right, and none are missing, and *then* you can ask "Okay, so what's wrong?"

author: sw_guy
author_rank: Regular Contributor
timestamp: April 30, 2024, 04:24:52 pm
content: Probably just the photo, but looks like R15 47k is yellow-violet-black-brown. Also R10 10k is worth checking.Anyway, it is easy to mix these:10k, 100k, 10M4k7, 47k, 4M7

author: themadhippy
author_rank: Super Contributor
timestamp: April 30, 2024, 06:09:06 pm
content: must say i aint impressed with the bypass that dont actually bypass.The diagram on page 18 breaks it down into sensible chunks ,test each bit for appropriate signals on the in and out of each block and narrow things down from there,as an example removing u2 and linking across its pins 3 and 7 will tell you if the input and output stages are working,is there a clock type signal on its pins 2 and 6 ,wots the lfo spitting out?

author: Scornn
author_rank: Contributor
timestamp: May 01, 2024, 11:04:22 am
content: So R15 was actually 4.7k when its supposed to be 47k, thats all fixed now but unfortunately it wasnt the problem

author: youngda9
author_rank: Regular Contributor
timestamp: May 01, 2024, 03:01:01 pm
content: What a poop show. The soldering was done by a blind monkey. The GND wire connection at the bottom of the board looks like there is a stray wire leading to the resistor just North of it. Left side of the resistor node looks like it may have a solder bridge to the diode above it (perhaps those nodes are supposed to be connected anyways).I would start with buzzing pin to pin on the ICs to see if there are any solder shorts beneath. Removing them will help to do that visually.

author: pipingmike
author_rank: Newbie
timestamp: May 02, 2024, 04:40:48 pm
content: You guys are so mean, no wonder people are hesitant to share projects

author: Benta
author_rank: Super Contributor
timestamp: May 02, 2024, 06:28:05 pm
content: @Scornn: don't be discouraged.You've had the misfortune to encounter a couple of the worst contributors on this forum (they prefer calling themselves "colorful").Most users are here to help.

author: DTJ
author_rank: Super Contributor
timestamp: May 03, 2024, 05:01:49 am
content: Try this.1) disconnect all the wiring to the PCB2) remove the ICs from their sockets.3) trim back the longer leads on the solder side.4) Check every resistor value with your multimeter against the build sheet / schematic.5) Check every capacitor value and also the polarity to see they have been installed correctly.6) Do the same for any diodes etc on the board.7) Solder power supply wires to the board.without the ICs installed check the voltage to the IC supply pins.9) refit the ICs. Check the orientation is correct.10) power it up - do any ic's get hot?

author: Scornn
author_rank: Contributor
timestamp: May 04, 2024, 11:26:53 am
content: Okay, so ive tried with a DPDT switch and its still the same, checked every resistor and diode and theyre all good. Ive replaced some caps except for 5 of them. The largest cap which is C7 220uf seems to get quite hot. Refit the ICs and I have a few TC072s and 062s. I have ordered a few more CD4046 chips and another V3207 and if that doesnt work then I have no god damn idea. Still bypass and power/LED works so we shall see when theres new chips arrive

author: CaptDon
author_rank: Super Contributor
timestamp: May 04, 2024, 01:14:27 pm
content: On a board like that the capacitor should not even get warm!!!! You have the cap in backwards or the power hooked up backwards!!! I would guess all of the I.C.s are probably shot. Probably time to shit can the thing and by a new one and carefully assemble starting from new. The unit you have is so hacked up by now it may never stand a prayer of working. The cap running hot tells me this thing is totally done for and you need to really decide if this project is within your skill set.

author: madires
author_rank: Super Contributor
timestamp: May 04, 2024, 02:36:43 pm
content: Yep, the 220µF electrolytic should stay cold. Please double-check its polarity. Are you using a 9V battery to power the circuit or something else? And I'd recommend to use colored wires for +9V, Gnd, In and Out to make troubleshooting and future repairs easier. For checking just the PCB it would help to remove the stomp switch and wire the PCB with a 9V battery, an input jack and an output jack (as in the PDF "Testing Your Effect").

author: themadhippy
author_rank: Super Contributor
timestamp: May 04, 2024, 02:47:54 pm
content: If the bypass is working something weird is going on,unlike most guitar pedals in bypass it still needs a working power supply and at least half of u1 to be working

author: madires
author_rank: Super Contributor
timestamp: May 04, 2024, 02:59:41 pm
content: Quote from: themadhippy on April 30, 2024, 06:09:06 pmPlease see page 14 (green wires). When the stomp switch isn't pushed the PCB's input is switched to ground and the output jack to the input jack.

author: themadhippy
author_rank: Super Contributor
timestamp: May 04, 2024, 03:09:30 pm
content: Quotebugger im miss reading the circuit,i thought s1 was the bypass

author: sw_guy
author_rank: Regular Contributor
timestamp: May 05, 2024, 05:41:28 am
content: How about taking new photos on both sides including all wires and connectors?