Build Your Own Clone Message Board

Folks,

Lazy sprocket 2.0 build for some (I thought) easy fun. No "new builder caveat"- so this has me stumped - and I am on losing side of needing bifocals.

Wasn't getting any swell effect (in fact it was reversed) and started troubleshooting- noticed the lowest diode under the attack side was reversed, fixed that, now nothing..only bypass and no LED.







Thoughts?

Tug on your wires, make sure they have a solid connection. Reflow your solder joints to make sure they are fully flowed and fill the eyelets. If you have a signal tester, you can find where the signal is dying out to help isolate the problem area(s). Make sure your component placement is correct, and let us know what you come up with.

_________________
The tone is in my hands?!
Email: nick@buildyourownclone.com

I don't see any components misplaced, so I would definitely start with this. More guidance here: viewtopic.php?f=9&t=52188

I assume you're sure that you mounted the JFET in the correct place and have tried adjusting the trimpot?

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

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

reflowed all points, JFET in correct slot, battery/wall plug/ etc, etc still nothing-

The concern I have is that somehow inverting that diode caused some other issue- particularly in hastening the failure of a component.

Are there any test points and voltages that are available that could help debug this?



thanks again in advance.

The LED is confusing me. Did the LED work before you swapped that diode, and then stopped working? I wonder if you caused some kind of short to power when you made that change.

_________________
Scott

My band, Austin Hollow

everything, including LED, was working aside from a strangely high decay (no intended effect). Once the diode switch nothing.

I am stumped as well, which is why I am asking for that SOS

I'd be checking voltages to see if the circuit is getting power. Do you have access to a multimeter and know how to use one to measure DC voltage?

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

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

yes, though I am terrible at calculating what is expected

The schematic shows what voltages you should see at the important parts.

http://byocelectronics.com/lazysprocketschematic.pdf


'+9v' is supposed to be your power supply voltage, so somewhere around 9v

'Va' will be your filtered 9v, and will be very close to the +9v voltage.

'Vref' is the voltage coming off the voltage divide, so it will be 1/2 your input voltage, typically around 4.5v.

If you look at page 4 of the 741 datasheet, you will see the pin designations: http://www.ti.com/lit/ds/symlink/ua741.pdf

Pin 7 will be your positive voltage, and should be the Va voltage.
pin 4 is your ground connection for the opamp, and should read 0.


If your LED isn't lighting, make sure you have proper voltage to the circuit, and that your ground connections are solid. The LED is switched directly from the footswitch, so it is sort of independent of the circuit. The power for the LED routes directly from the + eyelet on the board, through a 4.7k resistor, then into the anode (positive end) of the LED. The cathode (negative end) is then tied to lug 1 of the footswitch, with the ground connection being made by lug 2 of the footswitch, which is tied to ground.

_________________
The tone is in my hands?!
Email: nick@buildyourownclone.com

thank you: will look...stand by

Power at supply is 9.37v

Both Pin 7 and 4 are reading 9.37v

LED on negative end has continuity to lug 1 of the footswitch.

Admittedly hazy on the schematic regarding the end point of Vref test point, could you clarify for an old dog?

Can you pull the opamp and test again please? This shouldn't happen, and means there is a short between power and ground.

_________________
The tone is in my hands?!
Email: nick@buildyourownclone.com

Black is ground
Red is +9V
Purple is Va
Yellow is Vref



I also noticed some errors in the schematic, so I updated it, if you're following along with the schem, you should reload the PDF.

_________________
The tone is in my hands?!
Email: nick@buildyourownclone.com

same result with opamp pulled.

Also, let's get some more images please. This time show your updated soldering, your footswitch wiring, and power jack wiring.

_________________
The tone is in my hands?!
Email: nick@buildyourownclone.com

Tested all of the points mentioned and they are all reading either 0 or 9.36 (which is unexpected).






some liquid electrical tape on connectors to prevent shorting (the black stuff)

How is your output jack wired? If you orient them according to the instructions, the wires should cross. It could be that for the pic, they uncrossed, but just checking.

It's strange that you are getting no 1/2V (Vref) readings. I think next would be a continuity test to see if there is a short somewhere.

First, use ground as a reference, by that I mean place your meter into the continuity setting and place one lead to a ground location. If you install the jacks in the enclosure for this test, you can use a screw hole (I recommend this method because it's easy to just place a lead into the screw hole and leave it, instead of having to hold the probe to a ground location).

What you want to make sure is that all the ground locations have continuity and that none of the power locations have continuity when attached to ground, if that makes sense. The black spots in the image I posted should all beep, with none of the other locations doing so. If you see a spot that is connected to ground that shouldn't be, take a closer look at it to see if there is any stray solder or wire touching it.

Without the proper voltages, the circuit won't work right, so that is something you'll need to figure out first. Did you say it has the same symptoms on both a fresh 9v battery and a proper power supply? Make sure you are using either a fresh 9v or a 2.1mm tip-negative 9v power supply, preferably something designed for use in pedals.

_________________
The tone is in my hands?!
Email: nick@buildyourownclone.com

Everything offered as a solution/test have been done with a fresh 9v as well as a 1 SPOT wired connection.

CMOS has remained "unplugged"

All "ground" test points (the black ones in the illustration you provided) have continuity
No positive points (the red points indicated) have any continuity.

Retesting voltages yields the same results, and there is no LED when powered, and "plugged".

Starting to feel like this is crazytown for how silly the solution is, and I am, as always, in your debts for any help.

You mentioned the led ground has continuity to the stomp. Did you measure the voltage on Borge sides of the led? You should have about +4.5. I also noticed that the trimmer hasn’t moved positions and I didn’t see the answer to whether or not you adjusted it.


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_________________
Pedal building is like the opposite of sex. All the fun stuff happens before you get in the box.

Trimpot has been moved.

I am getting 0.0 voltage readings on either side of the LED with both 9v battery and wall plug.

But you’re getting power to the board?


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_________________
Pedal building is like the opposite of sex. All the fun stuff happens before you get in the box.

yes