# Problems with Caesar chorus



## Jkhicks (Jan 19, 2022)

I just finished the Caesar chorus only to find that Im not getting power through the jack. I can plug a 9v battery to the pedal and it gets hot to the touch. Take the jack out hook it to a 9v power source and it will turn on an unwired LED. With the jack in the pedal and the unwired LED touching the posi and negative jack post 
,I get nothing. Any help appreciated


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## benny_profane (Jan 19, 2022)

Post a picture of your jack and wiring.


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## Jkhicks (Jan 19, 2022)

benny_profane said:


> Post a picture of your jack and wiring.


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## Jkhicks (Jan 19, 2022)

It’s says file is too large for server. Photo is too large


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## jimilee (Jan 19, 2022)

Jkhicks said:


> It’s says file is too large for server.


Make it smaller, or post it somewhere and put the link here. Sounds like something is wired backward, but not necesarily.


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## Jkhicks (Jan 19, 2022)

finally. Lol


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## Stickman393 (Jan 19, 2022)

If the 9 volt gets hot when you plug it in to the pedal DC input, that means that your circuit is pulling *a lot* of current.

I would measure the resistance between positive and negative on your pedal.  I'd bet you'll read close to 0 ohms.  If that's the case, I would start looking at the ground and positive connections to your PCB, to the left of your depth pot.  I wouldn't be surprised if you've got a solder bridge or a whisker from your hookup wire creating a short circuit across your power supply.

Also - I noticed you haven't populated the LEDs in the LFO shape circuit.  Without these, your triangle LFO shape won't work.


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## Jkhicks (Jan 19, 2022)

Stickman393 said:


> If the 9 volt gets hot when you plug it in to the pedal DC input, that means that your circuit is pulling *a lot* of current.
> 
> I would measure the resistance between positive and negative on your pedal.  I'd bet you'll read close to 0 ohms.  If that's the case, I would start looking at the ground and positive connections to your PCB, to the left of your depth pot.  I wouldn't be surprised if you've got a solder bridge or a whisker from your hookup wire creating a short circuit across your power supply.
> 
> Also - I noticed you haven't populated the LEDs in the LFO shape circuit.  Without these, your triangle LFO shape won't work.


I blew up the picture above to look for that. I can’t see a bridge. Is it possible I have a bad pcb?


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## Jkhicks (Jan 19, 2022)

What leds go there?  I saw nothing on the build document


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## Robert (Jan 19, 2022)

Don't worry about this for now, figure out the power supply issue first, but...


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## Big Monk (Jan 19, 2022)

Jkhicks said:


> What leds go there?  I saw nothing on the build document


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## Robert (Jan 19, 2022)

Jkhicks said:


> I blew up the picture above to look for that. I can’t see a bridge. Is it possible I have a bad pcb?



The bridge could be on the back, not visible form the photos.

A bad PCB isn't _impossible_ of course, but not the most likely cause of this sort of problem.



See this little sliver of a wire strand right here?




If you have one of those right _here _(on the back side, they usually occur on the side the wire is entering the PCB) it could cause the problem you're having.





You'll have to pull the PCB out of the enclosure to check.   Post pics when you do, and go ahead and install those two LEDs while you're at it.


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## Jkhicks (Jan 19, 2022)

There was a stray on the back side. I’m getting 9v to the board,but not through the 9V1 zener. I’ve ordered the leds and a new zener. Also no power to the switch. I hope it’s the zener…edit. I just misssed the leds. I guess I thought those were just power indicators as usual.


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## Robert (Jan 19, 2022)

Voltage isn't supposed to pass through the 9V1 zener, it goes to ground.

It's purpose is to hold the voltage at 9.1V.    You should measure around 9V on one end, but no voltage on the other.


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## Jkhicks (Jan 19, 2022)

Then I have no idea…


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## Robert (Jan 19, 2022)

Check and see what voltage you have on pin 8 of one of the 4558 opamps.


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## Stickman393 (Jan 20, 2022)

Take a deep breath - you'll be fine.  Think of this as a learning opportunity.

Potentially uncomfortable truth: You probably either made a mistake, or you have a bad solder joint somewhere.  It's not a big deal.  Even experienced pedal builders fuck up from time to time, especially when taking on a new circuit.  It's normal, it's part of the process.  

It's extremely unlikely that you have a bad Zener.  MAYBE there's a bad component in the mix, but it's far more likely that there's simply a problem with the build that you're not aware of yet.  Double check all your component values.  Inspect the board for solder bridges or whiskers.  Figure out where the problem is before you go changing out components - trust me, de-soldering is time consuming, has plenty of potential to rip out a trace or two, and more often than not won't lead to the desired result.

Find, then fix.  The other way around will lead to frustration and a pedal-shaped hole in your wall, if you're like me.

The good news is that you can continue troubleshooting without the red LEDs for the triangle wave LFO.  Just know that the shape switch won't do anything until you get those red LEDs installed.


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## Jkhicks (Jan 20, 2022)

Robert said:


> Check and see what voltage you have on pin 8 of one o





Robert said:


> Check and see what voltage you have on pin 8 of one of the 4558 opamps.


I’m getting 9v there. On the upper pin on the right side of the chip


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## Jkhicks (Jan 20, 2022)

I’m getting power through the board except where you feed the switch. The board is completely dead there. I’ve disassembled the pedal and there are no bridges. Reflown some suspicious joints.


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## Stickman393 (Jan 20, 2022)

Have you double checked all component values?  It's tedious, but going through resistor-by-resistor and cap-by-cap could lead  you to something that is incorrectly placed.

Another step that could help us diagnose what's happening here: take your voltage to ground across all IC pins.  They're numbered like so:

1.       8
2.      7
3.      6
4.      5

Post those measurements for all 4 ICs.  That may help us pinpoint the problem 

Another question: does your LFO LED light up and pulse when you plug the pedal in?  If not, that's an indication that your LFO is not operational, in which case no signal will pass through your MN3207.  This should light up regardless of if the pedal is "on" or "off".


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## Jkhicks (Jan 20, 2022)

I’m using a depleted 9v battery with an adapter that plugs into the power jack. It show 7.3v which I’m getting to pins1234678. There is no power down to where the 3PDT hooks to the board so the switch is dead. The Mylar film capacitor in the C1 position has power on one side but not the other. I’m getting voltage all the way down the board until it reaches that C1 cap.


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## Jkhicks (Jan 20, 2022)

I’ve just completed testing all values of resistors and caps and they are correct. As far the the LFO,I’m waiting for those to arrive. All I have here are 5mm leds and they won’t fit. Thank you for trying to help.


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## benny_profane (Jan 20, 2022)

The LFO should function without the LEDs by the switch installed. All those LEDs do is alter the shape of the wave. When power is applied to the pedal, you should see the LFO indicator LED (i.e., the Rate LED) cycle.


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## Jkhicks (Jan 21, 2022)

Stickman393 said:


> Have you double checked all component values?  It's tedious, but going through resistor-by-resistor and cap-by-cap could lead  you to something that is incorrectly placed.
> 
> Another step that could help us diagnose what's happening here: take your voltage to ground across all IC pins.  They're numbered like so:
> 
> ...


TL022 pin one=7.23v,pin two=7.17v,pin three=6.9v,pin four=7.42v,pin five=7.1v,pin six=6.79v,pin seven=7.1v,pin eight 0v.
MN3707 pin one=0v,pin two=3.4v,pin three=6.3v,pin four=6.7v,pin five=7.26v,pin six=2.5v,pin seven=0v,pin eight=3.41v
MN3102 pin one=7.2v,pin two=3.3v,pin three=6.4v,pin four=6.4v,pin five=0v,pin six=3.4v,pin seven=6.2v,pin eight=6.7v
45580 pin one=3.6v,pin two=2v,pin three=2.5v,pin four=7.2v,pin five fluctuating 0-6v,pin six=3.5v,pin seven fluctuating 2-5v,pin eight 0v……..9v depleted battery supplying 7.7v to the pcb. I don’t remember the power fluctuations the first time I checked it earlier.


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## music6000 (Jan 21, 2022)

Jkhicks said:


> TL022 pin one=7.23v,pin two=7.17v,pin three=6.9v,pin four=7.42v,pin five=7.1v,pin six=6.79v,pin seven=7.1v,pin eight 0v.
> MN3707 pin one=0v,pin two=3.4v,pin three=6.3v,pin four=6.7v,pin five=7.26v,pin six=2.5v,pin seven=0v,pin eight=3.41v
> MN3102 pin one=7.2v,pin two=3.3v,pin three=6.4v,pin four=6.4v,pin five=0v,pin six=3.4v,pin seven=6.2v,pin eight=6.7v
> 45580 pin one=3.6v,pin two=2v,pin three=2.5v,pin four=7.2v,pin five fluctuating 0-6v,pin six=3.5v,pin seven fluctuating 2-5v,pin eight 0v……..9v depleted battery supplying 7.7v to the pcb. I don’t remember the power fluctuations the first time I checked it earlier.


This is how the 4558, TL022 pinout is. PIn 8 is power in = 9v & Pin 4 is GND!


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## Stickman393 (Jan 21, 2022)

Looks like your voltages are all over the place.  It also looks like you may have swapped the readings for the TL022 and the JRC4558.

Can you confirm that your voltages match the pattern in the photo that music6000 posted?

A few points from reading your posts: 
1) Reading different voltages across a capacitor is normal, a fundamental part of the capacitor design is a dielectric - that is, an insulator.  Something which does not allow for the passage of electrons.

They're often used in circuits to block DC voltage from one part of the circuit from influencing another part of the circuit.  Fun thing about caps - they don't allow DC to pass (DC will cause a capacitor to build a charge, but that charge won't release until the voltage acting on it is released).  It is this property that allows AC...E.G. audio signals...to pass across a capacitor...a trick of electromagnetism that I spent a good 30 minutes explaining to my apprentice earlier this week.

2) A lack of voltage as compared to ground simply means that there is no potential between that point and ground - that is, there is no difference in electrical pressure between the point that you are measuring and ground.  If you were to attach a wire between those two points, no electrons would flow.  This does not mean that there is a problem at this point unless you're measuring a point that is supposed to have some sort of potential to ground.

3)  You should not read much, if any, DC voltage on the left or right side of the footswitch - these are your input and output poles, and depending on the switch position they're either grounded or there is a capacitor between these points and any DC voltage source. The center pole may show potential to ground on the top terminal only but that will depend on the position of the switch as well.   If the switch is currently completing the ON/OFF indicator LED circuit to ground, you will not read DC voltage ANYWHERE on the switch.  If the switch is not completing that circuit, then you will see something in the range of your power supply voltage on the top center position ONLY.

If you do not see voltage on the center top terminal of your switch, it is either currently in the "effect on" position, or there is a problem upstream of that point.  That is, unless you have a bridge or a whisker or something shorting out the connections on your bypass switch.

-----

A lesson that stuck with me from my apprenticeship: In a troubleshooting mindset, you need to know what measurement you expect to see *before* you take a reading.  Otherwise it's just meaningless data.

That's where this board comes in.  We can help to interpret the data that you provide, but remember that none of us is sitting at your bench with a meter or an audio probe.  We can only see what is in focus and unobscured in your photos, and we can only interpret voltages if we know for certain where that measurement was taken.

Truthfully, I get it.  I know where you're at, because I was right where you are a little less than a year ago when I was first getting back into the whole DIY pedal thing.  I built a Klon that never got finished because I got too hasty with condemning components and eventually ended up ripping out a bunch of traces while de-soldering.  I posted a thread on another forum where I even questioned if my PCB was defective...which is a little less common than, say, getting a bad resistor.  Which is to say; buy a lottery ticket if you get a defective PCB.

Confirm those voltage readings for us, and it would probably be a good idea to build yourself an audio probe as well.


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## Jkhicks (Jan 21, 2022)

I think the whole thing is going in the trash.


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## Jkhicks (Jan 21, 2022)

I think I had the pots turned down. I’m gonna save the chips and enclosure, set the rest aside and try again with solid core 24g wire.


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## Stickman393 (Jan 23, 2022)

Sometimes that's all you can do, de-soldering can lead to board damage.  I've scrapped boards in the past; I built an unpleasant surprise that lived up to it's namesake.

Solid core wire is a good way to go: no whiskers.  I personally tend to use 26awg.  Just be careful not to put any strain on those wire to board connections and you should be fine.


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