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Hi guys, I recently made the Analog Vibrato pedal and to my surprise it was working great when I put it together! I went away for a weekend vacation and upon return the vibrato no longer works. I am getting the LED lighting up, a bypass signal, and when I turn the knobs sometimes a very faint vibrato appears. The ramp switch doesn't do anything. I have tried reflowing my solder joints but I am worried that with all the extra heating I might be frying my components. Can someone have a look at my board and see if anything jumps out that I might be missing? This is my first pedal build, first soldering project at all actually so I'm sure it's a fix that I'm not seeing. Thanks in advance!

Photos: https://imgur.com/a/gKz3Xc1

Pedal behavior of the kind you describe is nearly always due to a poor solder joint somewhere in the build. Looking at your photos, your component soldering on the PCB looks quite good. Your wiring....not so much. If it was my pedal, I'd go through and replace ALL of the wiring and clean up the footswitch and jack tabs with a solder sucker and/or desoldering braid before rewiring the pedal:

https://www.amazon.com/TBBSC-Desolderin ... B08XQF9WYV

https://www.amazon.com/gp/product/B008O9VLA2/

I'd also recommend reading through these informational posts to help improve your wiring quality:

https://www.byocelectronics.com/board/v ... f=9&t=6401

https://www.byocelectronics.com/board/v ... =9&t=52211

https://www.byocelectronics.com/board/v ... =9&t=33293

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks so much for the reply! I hadn't even considered the wiring as a culprit. I've just ordered a pump and wick so I will have a go at that over the weekend.

Yikes well in my attempt to get the wires out of the pcb I accidentally pulled out three of the solder pads on the component side. The ones labeled 1, 5, and 4 on the bottom left. Is this just ruined now?

It may well be salvageable, and perhaps without too much difficulty. It would be helpful to see crisply-focused photos of that corner of the PCB, both sides please. It will be time to use a continuity tester to see whether any parts of the affected pads that may still be attached to the PCB still connect to the other ends of their traces--luckily, pads 1,4, and 5 don't connect to lots of different places. If you like, we can help guide you to the places on the PCB where the other ends of the traces should be found. (If you are comfortable with reading schematic diagrams, you can try to match the connectivity shown on the schematic diagram to the lighter-green traces on the PCB to help see what you need to achieve, and where.) It's likely that you can just install some additional wire jumpers or leads to provide the continuity that may have been lost due to pad damage, and sometimes just a well-formed new solder joint can do the trick.

The good news is that the traces between all three of those eyelets and their PCB connections are located on the back of the PCB. So while the solder pads on the top of the board may be gone, if the ones on the bottom are still intact, you may have "dodged the bullet," as the saying goes. And even if some or all of those are also lifted, the damage is still quite easily repairable. But the first thing I'd ask you to do is to post a high-quality photo (good lighting & focus) of the back of the PCB where those eyelets are located so that we can see their condition.

FYI, here's what each of those eyelets connect to on the PCB:

• #1 - The cathode (round solder pad) of the LED immediately adjacent to the eyelet
• #4 - The trace that runs down the back of the board from the input jack tip connection. So this one would be a very easy fix--just disconnect the wire from the input jack tip to the IN eyelet and instead run a wire from the jack directly down to lug 4 of the footswitch.
• #5 - Connects to the first component of the effect circuit, the R1 10K resistor located just to the right of the LED.

And below is what a repair of all three broken eyelets (if necessary) would look like. The remainder of the footswitch would be wired as you currently have it.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thank you both for your replies. It looks like on the back the solder pads are in fine condition so that’s a plus! I don’t own a continuity tester so it would be great to avoid that step but obviously I’ll buy if needed. I’ve attached crisper photos here. Thanks again for the replies.

Yep, those pads on the back of the PCB look fine.

A continuity check is one of the settings available on almost all digital multimeters (DMM). If you don't own one of those....you should! They have many uses beyond DIY electronics projects. You can get a perfectly serviceable basic one at your local Harbor Freight or online for $10 or so. I picked this one up for $35 a while back and have been extremely pleased with its many functions and accessories:

https://www.ebay.com/itm/295549345897

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Ok got it, so basically I would use the MM to test from the solder pad to the pad that it leads to?

Basically, yes. I'd actually recommend testing from the wire or component lead of one side to that of the other--that way, you're also confirming that both of the solder joints are making good contact.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Alright so I got the MM and did the readings, looks like the continuity is fine. I've been working through the rewiring but have been having a hell of a time with it. Still no vibrato coming out. Is there a next step for identifying the bad connection? Am I correct in assuming that if the input and output jacks are producing a bypass signal than the issue is elsewhere?

Which (one or more) of these, if any, are correct in the pedal's current state?

(1) When in bypass, the signal fed to the input jack also appears at the output jack, and the LED is off.

(2) When NOT bypassed, the LED is on, and the signal fed to the input jack appears at the output jack, but with no vibrato effect, no matter how the DEPTH and RATE knobs are set, even if the RAMP toggle switch is OFF.

(3) When NOT bypassed, the LED is on, but no signal at all appears at the output jack.

I would recommend having the two internal trimpots at the centers of their ranges when investigating, for the time being.

If something else other than (1) (2) or (3) is going on, please describe it.



Yes, that is correct, but the "bypass" position really "bypasses" almost everything in the box, so "elsewhere" is a lot of territory!

Alright so I’ve got (1) and (2) right now. Haha ya that’s a good point on the bypass, I guess at least I won’t need to rework the wiring on the jacks again. Should I begin testing all the connections with the multimeter? Thank you for the continued help, you guys are all keeping me sane as I am in a bit over my head.

OK, then you've shown that the problem must be somewhere on the PCB, since you are getting "dry" signal all the way through the effect circuit. What you're missing is the "wet" signal that creates the vibrato effect. Time to crank up that multimeter and measure some DC voltage levels. I'd start with the 4558 IC (which functions as both the input and output buffers) and the TL022 IC that is at the heart of the LFO (low frequency oscillator) that creates the vibrato's pitch modulation. You need to get a full set of pin voltage readings on each of these IC's. Here's what to do:

Leave the Ramp switch off and set the Depth and Rate pots to their halfway points. Set your multimeter to the DC voltage mode, indicated by a solid line above a dotted one. Use the 20VDC range setting if it's not an auto-ranging meter. Your power source needs to be connected and there needs to be a cable in the input jack. If the pedal is assembled into the metal enclosure, put the black probe into one of the corner screw bosses of the enclosure--this is your ground connection. If the "guts" are out of the enclosure, use the sleeve tab of the input jack for the ground connection. Then touch the red probe to each point that you want to measure. See image below for the numbering of the pins. Report your results here. Be aware that some of the pins of the TL022 should show rapidly changing voltage levels, if the LFO is operating correctly.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Alrighty now we're getting somewhere! I used the MM to test the voltage levels of both chips you mentioned. Results below. Anything tagged with RN was producing radio noise through my amp when I touched those pins. It also seemed like when I had the black end on the input jack sleeve, I could only get a reading directly on the solder connection, and not on the majority of the metal sleeve above the connection. Is that normal? The TL022 readings were changing a lot like you said but I tried to grab the most common number. Thanks!

4558 IC
1 - 2.57
2 - 0.02, 2.55 (RN)
3 - 2.54 (RN)
4 - 0.04
5 - 2.52 (RN)
6 - 2.55 (RN)
7 - 2.54
8 - 4.8

TL022
1 - 2.44
2 - 2.44
3 - 2.38
4 - 0.04
5 - 1.69
6 - 1.29
7 - 2.30
8 - 0.02-4.80

OK, first things first: You have a power problem somewhere. Pin 8 of both of those IC's should be at your power source voltage, nominally +9VDC. You're only seeing about half of that.

From the ragged appearance of it, I would suspect either the DC jack connections to the PCB or the jack itself. Can you get a DC voltage reading from the + eyelet there on the tab at the top of the PCB?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Ah ok I see. I don't actually have anything plugged into the jack, I'm running off a 9V battery so would I get the reading from the + eyelet of the battery connection? Where am I putting the other end of the MM?

I should also mention I rewired the DC jack and it's a lot cleaner now. I also don't think I have an adapter with the right voltage or I would try what you had suggested. Just stuck with the battery for now, but if needed I can go pick one up.

Better get a fresh 9V battery--that one appears to be on its last legs. When using a battery for power, pull the cable out of the input jack when you're not using the pedal--this breaks the ground connection for the battery and keeps it from draining. The footswitch is NOT a power switch, contrary to what many people may think--it just switches the effect circuit in and out of the signal path, i.e. bypassed or engaged. The circuit is energized whenever power is connected to the pedal AND there's a cable in the input jack to provide the necessary ground path for the power source.


What you need is a 9V regulated P/S with a center-negative plug. Optimally, that would be a "brick" style supply with multiple isolated outputs--these run about $100 and up, depending upon number of outputs and features. This unit from MXR is a good one at a reasonable price: https://www.sweetwater.com/store/detail ... wer-supply

I you don't wish to spend that much, there are single supply units for a fraction of that price. We recommend staying away from the Truetone 1 Spot; it's a popular unit but seems to cause a lot of problems with BYOC pedals.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

You could put the "common" (probably with a black probe) at the - eyelet of the batter snap wire, and then the other (V, probably "red") at the + eyelet, and with a 9 V battery attached the meter should read somewhere between +7 V and +9.5 V, depending on how fresh the battery is.

It's not always easy to hold narrow probe tips on solder lumps while also keeping an eye on the meter, so we often look for a hands-free way to make that connection ("common"; black conventionally). Let's assume you are putting the "common" (black) probe at the circuit "ground," which is what we do most of the time. Sometimes there is a little alligator clip on the black probe and you can clip it to the ground (sleeve) lug of the input or output jack. Otherwise, you might sort of diagonal the narrow probe into the output jack sleeve (probably you have a plug in the input jack, as it is needed to complete the power circuit). If the guts are still in the box, you can stick it into one of the four enclosure screw locations, since it is nearly certain that the box itself is also connected to ground. If your wire to the input or output jack sleeve lug is well-soldered but without the lug hole filled with solder, you might be able to stick a narrow probe tip in there.

I almost hate to ask this, but is it possible that the problem is that the 9 V battery originally in use got mostly drained over the weekend and the remaining 4.8 V power supply is just not enough? The data sheets for the MN3102 and MN 3207 both claim that +4 V is sufficient, and if a signal is getting through with the pedal engaged then the 4558 can't be too unhappy with that power supply. But I do see on the BA6110 data sheet, in a figure, that +/- 2.4 V is implied to be ok, but the output at its pin 8 (which drives some current that helps the MN3102 do what it is supposed to do) would only be about 2 V, and perhaps that is not enough, given some diode drops that follow. Perhaps the MN3102 is generating the needed clock signals but they are not being modulated properly, hence no vibrato. The TL022 datasheet I am looking at claims +/- 2 V "works" but elsewhere it implies that the output can only get within 2 V of each rail, so that may be another way in which modulation could be absent.

Well I feel like an absolute idiot right now, just tried changing the battery and things immediately are working exactly as they should. Thank you so much for the suggestion and sorry for the time waste on what ended up being such an easy fix. Now I'm off to order a dedicated power supply

We are glad you are back in business and that you are not asking *us* about our own most stellar moments. You know, like the time I could not figure out why my newly-constructed pedal wasn't working and when I took the back off to start fiddling with it I saw the empty IC sockets.

Not to worry--we've all been there with the "silly stuff" that turns out to be a simple fix. Glad to hear that a new battery got your Vibrato vibrating!

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thank you both for your patience with this! This is such a welcoming community. I'm sure I'll be back soon enough with another issue on my next build lol.