Build Your Own Clone Message Board

I'm on day four of working on this octave pedal, I wanted to wait to ask for the forum's help until I had exhausted all of my available resources so here I am looking for some insight into why my pedal isn't working. When the pedal is off the signals flows through as expected. When the bypass footswitch is engaged the LED turns on the the signal cuts out entirely (no sound). When the bass only footswitch is engaged the LED turns on and the guitar signal and tone stay normal (no effect applied). Neither of the switches or potentiometers are doing anything when they're being adjusted.

I originally thought that I may have switched up some resistors (even though I sorted them out into respective piles before starting as I always do) so I double checked all the color bands with a magnifying glass, nope not the case. Yesterday (day 3 of staring at this board) I decided to go through and use my meter on each individual resistor and while I had correctly color coded each of my resistors it turns out that 14 of them are not coming up as the proper impedance. The resistors in each of the following spots are measuring at extremely incorrect values, R46, R43, R44, R60, R61, R6, R8, R5, R39, R25, R29, R19, R20, R15. If it would help I can post the values that they're measuring at, so let me know if that info is pertinent to my issue.

I'm so sick of staring at this board and trying to figure out why it doesn't work so please someone give me some insight before I start going crazy.

I haven't built this one, but I can tell you this much - resistors measured in circuit will OFTEN give erroneous readings. So don't worry about what your meter is telling you - those resistors are probably in parallel with others, which will change your reading accordingly.

Your time might be better spent with a good magnifier, inspecting each solder joint. You want to watch out for unintentional bridges, joints that are dull rather than shiny, and joints that look like a bubble or blob rather than a nice pointy cone. Reflow any ones that look suspect using a hot, clean, shiny, tinned iron tip. 3 second or so should be enough - just make sure the solder liquifies and the iron tip is in contact with the component leg, the pad, and the wet solder. That should fix up any bad joints. Might want to trim away those frayed wire ends too, just in case.

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Thank you for clarifying the resistor issue I thought I was having CaptainPeyote.

I've gone through and reflowed my joints that weren't perfect cones but I'm still having the same issue... there weren't any bridges to begin with and I even desoldered a few joints that looked like they could have been close.

Depending upon how they are connected in the circuit, measuring installed resistors may or may not give the expected values. As Cap'n has noted, there may be parallel resistance paths present, which causes the resistance to read lower than the resistor rating.


Very sound advice. It only takes one bad joint in the wrong place to render a pedal mute. Also clean up any stray bits of solder and trim down protruding component lead ends to the top of their solder joints.

If the pedal still isn't working after this inspection & touch up process, you'll need to get into more in-depth troubleshooting methods. That effect has a lot of IC's, which tend to be the most failure-prone of the components used in these effects.

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

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

Sorry that it's taken me a bit to get back to you guys I had to walk away from this pedal and work on some other projects so that I could come back to it with fresh eyes. I've reflowed the entire board, made sure that I didn't have any bridges, and I've trimmed all excess wires and leads but it's still having the same issues as before. Is there a resource that anyone could recommend on how to troubleshoot the IC chips?

Another update, after continuing to try and reflow parts of the board now the left LED is on at all times and only turns off when I engage the right footswitch. In addition to the left LED not turning off I now have no signal unless the right footswitch is engaged.

I wouldn't worry about the left side LED always being on at this point--it's strictly an indicator of whether the effect is bypassed or not, and is not part of the effect circuit. Also, that particular LED is operated by a different type of circuit known as a "Millennium Bypass" that's often employed when there aren't enough unused footswitch lugs for the more common mechanical bypass hook-up.

You stated, "... I now have no signal unless the right footswitch is engaged." Are you saying that the effect works when engaged, but only with the "Bass Only" switched on? Or do you not have clean signal when the left footswitch is in bypass?

A fresh set of photos may be useful, too.

Do you by any chance have another pedal available with a socketed dual op amp? Doesn't have to be a JRC4558D--any standard dual op amp (TL072, TL082, NE5532, OPA2134A, etc.) would be fine.

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

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

+1 to everything DVM said.

If you have mix fully CW and the ringer switch off, do you get any signal in effect mode? How about the aux send jack? Do you have signal there in both bypass and effect modes?

It sounds like the op amps might not be getting the voltage they need to pass signal. Take voltage readings from pins 4 and 8 from each op amp. Pin 4 should have close to -9 volts DC and pin 8 should have close to +9vdc. The remaining pins should be close to 0vdc.

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MasterDelayer/Reverbrador/Ampaholic/TopJacker

I apologize for not being specific with my statement about the guitar signal. When the bass only footswitch is engaged there is no effect at all, I'm just getting the dry guitar signal and I no longer have any dry signal unless the bass only footswitch is engaged (which is the only way the left LED will cut out). This has me thinking that when I reflowed the board I screwed something up because in the beginning I just wasn't getting the pedals effect. When I get home from work I'll open up some of my other pedals and see if I can pull an op amp from one and I'll get some fresh photos online tomorrow afternoon as well.

To answer Morgans questions about the signal, the only time I'm getting any signal at all is when the bass only footswitch is engaged, this is also causing the left LED to turn off, and when I engage the bypass footswitch the LED doesn't cut off and the noise that comes through my amp is horrible to say the least. I will test the op amps tomorrow, do I need to remove the IC's from their sockets or can I test the ends on the solder side of the board?

So, so both outputs behave the same way? The reason I ask is that the aux out has a different pathway.

To get voltage readings from the op amps, you touch the red probe to the op amp pins, above the pcb you can access them where they insert into the sockets.

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MasterDelayer/Reverbrador/Ampaholic/TopJacker

OK, bear with me here, because this is pretty convoluted:

The way the Millenium Bypass (M/B) circuit for the main footswitch indicator LED works is this: When the M/B circuit is not connected to the output of the effect circuit, it lights up the LED. This is because it needs a connection to the ground resistor at the output of the effect circuit for the M/B circuit to switch off the LED. Lug 8 of the main footswitch is the effect circuit output, lug 7 is the connection to the main output jack, and lug 9 connects to the M/B circuit. (The Divided Octave schematic shows lug 9 going to the output and 7 to the M/B, but this is incorrect.) So when the footswitch is in the engaged position, the M/B circuit lacks the connection to the effect circuit needed to turn off the LED. When the footswitch is in bypass, the M/B-effect circuit connection is made and the LED shuts off. So the fact that your main footswitch LED isn't always shutting off when it should indicates that the connection to the effect circuit isn't always being made. So what's up with that?

The connection to the effect circuit can go two ways, depending upon the position of the "Bass Only" (B/O) footswitch. When it's engaged, the B/O LED lights up (it's a regular LED circuit, not another M/B) and lug 8 connects to lug 7, which is the B/O portion of the effect circuit. When not engaged, lug 8 connects to the full bass + ringer effect circuit output at lug 9. (Lugs 7 & 9 are switched on the schematic for this footswitch, too.) In both cases, the required ground resistor for the M/B LED turn-off is present--R34 for the full effect path and R17 for the B/O path. See labeled PCB diagram below.

What appears to be happening in your pedal is that connection through the B/O switch to the ground resistor is working for the bass setting but not for the full effect path. This would seem to have to be due to one of three possibilities:

1. The B/O switch is not making the lug 9-lug 8 connection internally in the switch, i.e. the switch is bad.
2. There's a problem with the wire connection between lug 9 of the B/O switch and the PCB.
3. There's a problem with a solder connection on either R34 or R35 on the PCB.

Of these, the first one is probably the most likely. But you can determine which of these is the problem by disconnecting the power source, setting the B/O switch to the full effect position and testing for continuity/resistance from lug 8 of the B/O switch to (1) lug 9, (2) the top leg of R35, (3) the top leg of R34, and (4) ground. The resistance results should be ~0 for (1) and (2), approx. 560 ohms for (3) and about 22.6 Kohms for (4).

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

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

Thank you for the detailed response duhvoodooman, my readings with R34 and R35 were along the values that you stated they should be, but both lugs give a wildly fluctuating reading for about 10-15 seconds then stop at either .5 or .6.

I've inspected the connections for R34, R35, and lug 9 between the pcb and the footswitch as well and they're all solid. So should I order another footswitch and trying that next? Or is a .5/.6 reading close enough to 0 when taking these kinds of readings?

Also I decided to resolder some of the other footswitch to pcb connections and now both LED's are working properly and I'm back to my original issue (no effect) , I'm starting to lose hope that I'll get this pedal working because it seems to just be one thing after another haha.

Take heart! We have not yet begun to fight!!

Please answer the following questions:

1. Have you done the DC voltage measurements yet on pins 4 and 8 of each of the JRC4558D op amps? If so, what did you find? For reference, for my Divided Octave supplied with 9.55VDC, all the pin 4's read -8.2V and the pin 8's are +8.8V.
2. I am still not clear whether the pedal passes clean, unprocessed signal when the main footswitch is off. Yes or no?
3. Do you have signal output through the AUX output jack? This jack should pass clean signal for either of the main footswitch settings. When the main footswitch is engaged, the AUX output signal goes through a zero-gain buffer on the PCB, but should change very little in tonal character vs. the bypass signal, and it will not be affected by any of the pedal controls.
4. How about that fresh set of pics?

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

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

I'm glad that your optimistic about this situation I'm in DVM!

When supplied with both a standalone 9v adapter and as part of my one spot chain I'm not getting any readings at all from any of the IC chips. I've measured voltage before but never with this meter so I'm not sure if it's the pedal or the cheap meter that I'm using.

The pedal doesn't pass any signal at all when either of the foot switches are off or on, the only time I'm getting a clean unprocessed signal is when I use the AUX output instead of the normal output.

Attached is a new picture of the solder side of the board.