# Fried Klon Zeners



## Svenson007 (Feb 23, 2022)

Hey guys I asked a question I thought I knew the answer to a while ago here to confirm before building a Klon for somebody. It was confirmed. I asked if a 12v 1n5242 1/2 watt Zener diode was ok instead of the 1watt version. I didn’t and other people didn’t see a problem. Well one fried while I was testing it with one 9v adapter. I fixed it and played it with an ehx adapter no problem. I sold one of the two builds and when the guy got it he said he plugged in a one spot and it won’t work.

Why would this diode fail like that?? It’s super disappointing as I’ve never had a build fail like that and he seems annoyed and is getting his money back. I don’t think he’s open to clipping the diode and having me guarantee that if anything happens to the chip it’s on me.

I knew I should have left it out and just risked the chip… as it can handle plenty of power.

So my question again is. Why the heck wound these zeners be failing?


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## music6000 (Feb 23, 2022)

Svenson007 said:


> Hey guys I asked a question I thought I knew the answer to a while ago here to confirm before building a Klon for somebody. It was confirmed. I asked if a 12v 1n5242 1/4 watt Zener diode was ok instead of the 1watt version. I didn’t and other people didn’t see a problem. Well one fried while I was testing it with one 9v adapter. I fixed it and played it with an ehx adapter no problem. I sold one of the two builds and when the guy got it he said he plugged in a one spot and it won’t work.
> 
> Why would this diode fail like that?? It’s super disappointing as I’ve never had a build fail like that and he seems annoyed and is getting his money back. I don’t think he’s open to clipping the diode and having me guarantee that if anything happens to the chip it’s on me.
> 
> ...


The original Klon uses a 1n4742.
 The standard 1 SPOT is 1500ma, it was probably too much surge!
If you leave it out and he uses 18v by accident he'll fry the Charge pump


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## Big Monk (Feb 23, 2022)

Svenson007 said:


> Hey guys I asked a question I thought I knew the answer to a while ago here to confirm before building a Klon for somebody. It was confirmed. I asked if a 12v 1n5242 1/4 watt Zener diode was ok instead of the 1watt version. I didn’t and other people didn’t see a problem. Well one fried while I was testing it with one 9v adapter. I fixed it and played it with an ehx adapter no problem. I sold one of the two builds and when the guy got it he said he plugged in a one spot and it won’t work.
> 
> Why would this diode fail like that?? It’s super disappointing as I’ve never had a build fail like that and he seems annoyed and is getting his money back. I don’t think he’s open to clipping the diode and having me guarantee that if anything happens to the chip it’s on me.
> 
> ...



Because you are putting more than 1/4W through them?


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## Svenson007 (Feb 23, 2022)

Big Monk said:


> Because you are putting more than 1/4W through them?


I meant 1/2 watt.I’m guessing this is a dumb question, but how do our other components survive down to 1/8 watt then?


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## Svenson007 (Feb 23, 2022)

music6000 said:


> The original Klon uses a 1n4742.
> The standard 1 SPOT is 1500ma, it was probably too much surge!
> If you leave it out and he uses 18v by accident he'll fry the Charge pump


My bad the ones I have are 1/2 half watt. The original Klon is 1 watt. Some very knowledgeable (much more then me) people said it’s fine. Some top posters. 

Are you sure about the one spot? Wouldn’t it be frying all sorts of pedals? 1500 ma?? 

If your not building tens of thousands of pedals a small chance of replacing a chip isn’t a huge deal I wouldn’t think. At least they wound know it’s their fault for plugging in 18v.


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## music6000 (Feb 23, 2022)

Svenson007 said:


> I meant 1/2 watt.


You said you fried one when Testing, That should have sent you a Red Flag!
Most pedals don't have the 1N4742 diode protection for the Charge Pump & most people don't put 18v in them *BUT*.
Does your pedal state 9V DC only on the face????
I use a 9v 1000ma power supply, the pedal only draws what it needs!!! 


Svenson007 said:


> My bad the ones I have are 1/2 half watt. The original Klon is 1 watt. Some very knowledgeable (much more then me) people said it’s fine. Some top posters.
> 
> Are you sure about the one spot? Wouldn’t it be frying all sorts of pedals? 1500 ma??
> 
> If your not building tens of thousands of pedals a small chance of replacing a chip isn’t a huge deal I wouldn’t think. At least they wound know it’s their fault for plugging in 18v.


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## music6000 (Feb 23, 2022)

Sorry, the 9v 1Spot Single is actually 1700ma!


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## Svenson007 (Feb 23, 2022)

music6000 said:


> Sorry, the 9v 1Spot Single is actually 1700ma!


So basically he fried it. Anyways I’m getting mixed up. I build nice looking well soldered pedals, but when it comes to very finicky circuits I’m still a bit ignorant. I’ve learned a lot but there is always something new.

I’m a bit confused because you say you use a supply with 1000ma and pedals only draw what they need. That was my understanding. So why would the one spot with 1700ma be too much surge? Isn’t that contradictory?

I just read that some Klon clone builders clearly state not to use a one spot because the voltage varies too much and can out out significantly more then 9v dc. That seems about right.


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## music6000 (Feb 24, 2022)

Svenson007 said:


> So basically he fried it. Anyways I’m getting mixed up. I build nice looking well soldered pedals, but when it comes to very finicky circuits I’m still a bit ignorant. I’ve learned a lot but there is always something new.
> 
> I’m a bit confused because you say you use a supply with 1000ma and pedals only draw what they need. That was my understanding. So why would the one spot with 1700ma be too much surge? Isn’t that contradictory?
> 
> I just read that some Klon clone builders clearly state not to use a one spot because the voltage varies too much and can out out significantly more then 9v dc. That seems about right.


My mate has 2 Klons, One Original & One I built to spec including the Enclosure, I own 2 that I built for myself as per Original Specs.
He has used a One Spot for close to 10 years with the Klons & never had an Issue!!!

The Issues were the time he plugged 18v after the first time he plugged 18v & fried the 1N4742 & CUT it so it would still work.
Fried the Charge pump under all that Goop
Here is my repair:






Here is my Klone:


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## jesuscrisp (Feb 24, 2022)

I know it's popular to shit on the One Spot, but I've never had any issues with it frying pedals, charge pump or not. 
If I fried anything with it, it was because of sloppy work shorting something out. 

More than anything your story sounds like there is some fault in the build that makes the diode fail. Or you had some serious bad batch with those diodes. 

My advice in general is to replace the diode with a small current limiting resistor. If that also fries in your build though, you know it's not the diode's fault.


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## Robert (Feb 24, 2022)

The mA rating of the power supply isn't the reason the zener diode failed...   The circuit was powered on a voltage above 12V or the zener diode was defective.   The wattage of the zener isn't critical in _normal_ operating conditions because it isn't conducting significant current.    The wattage comes into play when over-voltage or reverse polarity is applied.

You could have used a 100,000mA power supply, as long as the power supply voltage was below the zener voltage of the diode it would not cause any problems.   I use a little OneSpot Slim 1700mA supply at my bench, it has never caused any problems and regulates just fine.

Parallel (diode to ground) polarity / over-voltage protection is a bad idea, but it's how the original circuit was designed.    Replacing the wire from the positive lug of the DC jack with a 100 ohm resistor probably wouldn't be a bad idea and could prevent future failures.


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## music6000 (Feb 24, 2022)

Svenson007 said:


> Hey guys I asked a question I thought I knew the answer to a while ago here to confirm before building a Klon for somebody. It was confirmed. I asked if a 12v 1n5242 1/2 watt Zener diode was ok instead of the 1watt version. I didn’t and other people didn’t see a problem. Well one fried while I was testing it with one 9v adapter. I fixed it and played it with an ehx adapter no problem. I sold one of the two builds and when the guy got it he said he plugged in a one spot and it won’t work.
> 
> Why would this diode fail like that?? It’s super disappointing as I’ve never had a build fail like that and he seems annoyed and is getting his money back. I don’t think he’s open to clipping the diode and having me guarantee that if anything happens to the chip it’s on me.
> 
> ...


I was being polite in saying it may have had a surge,
You admitted to frying the 12v 1n5242 1/2 watt Zener.
Was it the same pedal you sent him???
It should have been fine with a 9v power supply, something else has played a part In Frying it the First Time around!


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## Svenson007 (Feb 24, 2022)

music6000 said:


> My mate has 2 Klons, One Original & One I built to spec including the Enclosure, I own 2 that I built for myself as per Original Specs.
> He has used a One Spot for close to 10 years with the Klons & never had an Issue!!!
> 
> The Issues were the time he plugged 18v after the first time he plugged 18v & fried the 1N4742 & CUT it so it would still work.
> ...


Cool Klon dude. That’s some tidy de-gooping. I’d have no idea how to go about that!


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## Svenson007 (Feb 24, 2022)

jesuscrisp said:


> I know it's popular to shit on the One Spot, but I've never had any issues with it frying pedals, charge pump or not.
> If I fried anything with it, it was because of sloppy work shorting something out.
> 
> More than anything your story sounds like there is some fault in the build that makes the diode fail. Or you had some serious bad batch with those diodes.
> ...


I might try a small current limiting resistor. This happened on two separate builds. Something is fishy.


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## Svenson007 (Feb 24, 2022)

music6000 said:


> I was being polite in saying it may have had a surge,
> You admitted to frying the 12v 1n5242 1/2 watt Zener.
> Was it the same pedal you sent him???
> It should have been fine with a 9v power supply, something else has played a part In Frying it the First Time around!


No these were two separate builds. That’s why it’s so weird 🤔


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## Svenson007 (Feb 24, 2022)

Robert said:


> The mA rating of the power supply isn't the reason the zener diode failed...   The circuit was powered on a voltage above 12V or the zener diode was defective.   The wattage of the zener isn't critical in _normal_ operating conditions because it isn't conducting significant current.    The wattage comes into play when over-voltage or reverse polarity is applied.
> 
> You could have used a 100,000mA power supply, as long as the power supply voltage was below the zener voltage of the diode it would not cause any problems.   I use a little OneSpot Slim 1700mA supply at my bench, it has never caused any problems and regulates just fine.
> 
> Parallel (diode to ground) polarity / over-voltage protection is a bad idea, but it's how the original circuit was designed.    Replacing the wire from the positive lug of the DC jack with a 100 ohm resistor probably wouldn't be a bad idea and could prevent future failures.


Thank you! I’m honestly leaning toward defective diodes. It happened on both klons I built. I’m going to try the 100ohm resistor.


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## music6000 (Feb 24, 2022)

Svenson007 said:


> Thank you! I’m honestly leaning toward defective diodes. It happened on both klons I built. I’m going to try the 100ohm resistor.


Can I ask why you used MAX1044, they can only handle around 10 volt Maximum Input?
Your Max 1044 Charge pump should crap out before your 1N5242, that 1/2 watt may have saved it ?????
They are not a  popular choice, TC1044S & 7660S can handle 12 Volts.
The only one I will use is *7660SCPAZ. *


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## Svenson007 (Feb 24, 2022)

music6000 said:


> Can I ask why you used MAX1044, they can only handle around 10 volt Maximum Input?
> Your Max 1044 Charge pump should crap out before your 1N5242, that 1/2 watt may have saved it ?????
> They are not a  popular choice, TC1044S & 7660S can handle 12 Volts.
> The only one I will use is *7660SCPAZ. *


I just wanted to build it as an exact clone. Also I wasn’t sure if maybe there was a reason for it that would be circuit dependant. Like a high pitched whine etc. I have some alternate charge pumps around. I’ll give em a try. I have used the max before with no problems, but I’ve also heard plenty of horror stories. I hate using components that are pushing it tolerance wise.


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## Betty Wont (Feb 24, 2022)

If you want to build an exact clone, you'll need to goop the hell out of the wrong choice of charge pump.


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## Bricksnbeatles (Feb 24, 2022)

Any reason you couldn’t just use an LM317 with a 240 Ω and 1.5K Ω resistor pair to regulate anything up to 40V down to 9.06V before the charge pump? It would only add three components, and instead of frying from over voltage like the zener, it would just step every down to a level that’s consistently safe for the charge pump circuit. Am I missing something?


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## Svenson007 (Feb 23, 2022)

Hey guys I asked a question I thought I knew the answer to a while ago here to confirm before building a Klon for somebody. It was confirmed. I asked if a 12v 1n5242 1/2 watt Zener diode was ok instead of the 1watt version. I didn’t and other people didn’t see a problem. Well one fried while I was testing it with one 9v adapter. I fixed it and played it with an ehx adapter no problem. I sold one of the two builds and when the guy got it he said he plugged in a one spot and it won’t work.

Why would this diode fail like that?? It’s super disappointing as I’ve never had a build fail like that and he seems annoyed and is getting his money back. I don’t think he’s open to clipping the diode and having me guarantee that if anything happens to the chip it’s on me.

I knew I should have left it out and just risked the chip… as it can handle plenty of power.

So my question again is. Why the heck wound these zeners be failing?


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## Robert (Feb 24, 2022)

Bricksnbeatles said:


> Am I missing something?



You couldn't power the circuit (properly) at 9V because of regulator dropout.

The Klon is one of the only circuits I know of that even bothers to attempt to protect the charge pump from over-voltage....   I'd be tempted to just omit the zener altogether.


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## benny_profane (Feb 24, 2022)

Robert said:


> You couldn't power the circuit (properly) at 9V because of regulator dropout.
> 
> The Klon is one of the only circuits I know of that even bothers to attempt to protect the charge pump from over-voltage....   I'd be tempted to just omit the zener altogether.


Every VFE pedal would like to have a word with you.


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## fig (Feb 24, 2022)

Robert said:


> I'd be tempted to just omit the zener altogether.


As opposed to omitting it partially? You sly dawg you.


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## benny_profane (Feb 24, 2022)

I can see the utility in the zener to protect in cases of transient spikes. But as a protection measure for using the wrong power supply, destructive methods should be considered bad practice.


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## music6000 (Feb 24, 2022)

Svenson007 said:


> I just wanted to build it as an exact clone. Also I wasn’t sure if maybe there was a reason for it that would be circuit dependant. Like a high pitched whine etc. I have some alternate charge pumps around. I’ll give em a try. I have used the max before with no problems, but I’ve also heard plenty of horror stories. I hate using components that are pushing it tolerance wise.


The Klon only used 7660SCPA, not Max1044!!!!!
Here is the most accurate PCB below :


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## Coda (Feb 24, 2022)

Bricksnbeatles said:


> Any reason you couldn’t just use an LM317 with a 240 Ω and 1.5K Ω resistor pair to regulate anything up to 40V down to 9.06V before the charge pump? It would only add three components, and instead of frying from over voltage like the zener, it would just step every down to a level that’s consistently safe for the charge pump circuit. Am I missing something?



Toan = mojo…


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## music6000 (Feb 24, 2022)

Robert said:


> You couldn't power the circuit (properly) at 9V because of regulator dropout.
> 
> The Klon is one of the only circuits I know of that even bothers to attempt to protect the charge pump from over-voltage....   I'd be tempted to just omit the zener altogether.


I know why from First Hand experience, Took me around 2hrs with a dremel to get the Black Goop off that Klon fried 7660S Charge Pump after the 1N4742 was clipped after receiving 18 volts !!!!!!!!!!!!!!!!!!!!!!!!!!!!!


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## music6000 (Feb 24, 2022)

Svenson007 said:


> I just wanted to build it as an exact clone. Also I wasn’t sure if maybe there was a reason for it that would be circuit dependant. Like a high pitched whine etc. I have some alternate charge pumps around. I’ll give em a try. I have used the max before with no problems, but I’ve also heard plenty of horror stories. I hate using components that are pushing it tolerance wise.


Trust me, Change to the 7660SCPAZ, I have never had an Issue with around 50 Builds using them!!!


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## Svenson007 (Mar 7, 2022)

Robert said:


> You couldn't power the circuit (properly) at 9V because of regulator dropout.
> 
> The Klon is one of the only circuits I know of that even bothers to attempt to protect the charge pump from over-voltage....   I'd be tempted to just omit the zener altogether.


I did omit it on my last build. Smooth sailing so far.


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## Svenson007 (Mar 7, 2022)

music6000 said:


> Trust me, Change to the 7660SCPAZ, I have never had an Issue with around 50 Builds using them!!!


Think I’ll do that man!


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