# Is this pedal beyond repair?



## Adcandour (Apr 21, 2013)

I made the mistake of plugging in a boss adapter when this thing needed a 9v 300mA one. This is the Digitech Drop pedal, if that helps.

I took a photo trying to look for anomalies, but realized quickly that I'm an idiot.

Not sure what to do, or if there is anything I_ can_ do. Any input before I wrap it up, and sell it to your naive children?


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## soldierscry (Jan 20, 2008)

Nothing looks toasted. What happens when you plug the correct adapter in?


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## Adcandour (Apr 21, 2013)

soldierscry said:


> Nothing looks toasted. What happens when you plug the correct adapter in?


Absolutely nothing. IIRC, when I but in the boss one initially, the light did light up, but nothing happened sonically.


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## Budda (May 29, 2007)

Did you buy new? As in can you go swap it out?


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## mhammer (Nov 30, 2007)

If any of the digital circuitry is pooched, then the pedal is essentially history, unless Digitech is wiling to sell you a new board for you to install.

HOWEVER....

Being a digital pedal from a major manufacturer, I'm assuming that the external power jack will be for 9Vdc, and that the external power is being down-regulated to +5VDC or 3.3VDC, as evidenced by the big baby blue electrolytic caps in the corner, and the 3-pin regulator just adjacent to the rear end of the power jack. If something is going to fry, as a result of "mis-powering" it will likely be there.

That said, if you're asking this sort of question, you're probably not in a position to troubleshoot or repair anything that uses surface-mount components.

What is the difference between what you plugged in, and what you feel you should have plugged in? For instance, was one simply higher current-capability than the other, but but the same voltage and polarity? Was the "wrong" one a higher voltage? Did it have the opposite polarity? (outside ground, instead of V+)

Quick recap on PSUs: When an internal battery gets switched off via the insertion of an external power source plug, the outside of that power plug *must* be positive (in at least 98% of cases), simply because of how the switching in the jack works. When there IS no internal battery supply to switch off (typically true of digital pedals), then it becomes the manufacturer's perogative as to whether to use outside-pos or outside-ground. Although not absolutely foolproof, outside-ground provides a little extra measure of end-user safety. If you're touching your sink faucet and holding the plug in your fingertips, the chance of zapping is reduced. 

On the other hand, the convenience of standardization is a strong magnet, so most manufacturers - assuming they have some direct or indirect involvement with battery-operated devices - are going to opt for outside-pos as the standard, because it requires less explanation and fewer caveats to consumers, and THAT provides a measure of product safety and fewer repairs/returns.


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## Adcandour (Apr 21, 2013)

Budda said:


> Did you buy new? As in can you go swap it out?


Unfortunately, used on reverb.


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## Adcandour (Apr 21, 2013)

mhammer said:


> If any of the digital circuitry is pooched, then the pedal is essentially history, unless Digitech is wiling to sell you a new board for you to install.
> 
> HOWEVER....
> 
> ...


Thanks Mark. 

I used a 1 Spot adapter (on a daisy chain) that just says 9VDC on the box. The pedal is also 9VDC. 

Nothing looks obviously wrong in the area you mentioned. Maybe I should just put it together and try another adapter, or order one direct from digitech? 

I don't suppose blowing on it like it's a nintendo cartridge would help? (I'll have to ship it for my father for that).


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## J-75 (Jul 29, 2010)

mhammer said:


> If any of the digital circuitry is pooched, then the pedal is essentially history, unless Digitech is wiling to sell you a new board for you to install.
> 
> HOWEVER....
> 
> ...


Wouldn't *all* DC devices have a polarity reversal diode by default? It's a no-brainer.
Didn't Boss flip polarity sometime in the past, hence they have two types of AC adapters - 'A' and 'N' ?


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## soldierscry (Jan 20, 2008)

For reference:

Power
Power Consumption:
2.3 Watts (< 250 mA @ 9 VDC)


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## toby2 (Dec 2, 2006)

Contact Erikson in Quebec and ask them what their repair policy is like for this sort of thing .


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## mhammer (Nov 30, 2007)

J-75 said:


> Wouldn't *all* DC devices have a polarity reversal diode by default? It's a no-brainer.
> Didn't Boss flip polarity sometime in the past, hence they have two types of AC adapters - 'A' and 'N' ?


You're right about the no-brainer part, and I suspect many, if not most, big-name pedals do.

Boss has made pedals and externally powered units that did not use internal battery as an option. So, yes, I think they did have both polarities going on in different PSUs. I know I always have to check my old BF-1 units, when I pull them out of the drawer, to verify what the polarity of the power plug is. Neither of them can use batteries.


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## vadsy (Dec 2, 2010)

The pedal is standard, center pin negative polarity. Most Boss adapters are negative pin, in fact I have never seen a reverse polarity Boss power supply. I don't think you fried it. The only thing I could think of right now is you didn't give the pedal enough power. The pedal needs around 300mA and most Boss adapters only put out 100mA. That being said the One Spot gives up to 1700mA, center pin negative, and unless you loaded it down with a whole bunch of other pedals at the same time, it should power the Droptune just fine. 


Sent from my iPhone using Tapatalk


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## High/Deaf (Aug 19, 2009)

At 1.7A, I would assume that OneSpot is a switchmode power supply. 

I had a 1A Godlyke switchmode supply go into some sort of thermal runaway. It briefly produced something higher than 9V DC, possibly as high as AC line voltage, that fried about 4 pedals downstream. I smelt it before I heard it - that's how quickly it happened and how much current was passed through one of the pedals (not sure which one was the first 'fuse'). Troubleshoot this like the front end got hit with 170V p-p. I'd check the caps and regulator first.

I won't touch Godlyke crap for love nor money anymore and am somewhat suspicious of switchmode supplies in general. Analog supplies do everything I need, and although they also fail, they don't wipe out everything else on the way.


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## sulphur (Jun 2, 2011)

Don't digital pedals get sketchy when daisy-chained?
I know that Ryan @ Dr Scientist warns agianst this with his digital units.

The only pedal that I got in that I had trouble like this, was a power hungry 2-300 mA modulation effect.
It wouldn't work until I fed it enough mAs.


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## mhammer (Nov 30, 2007)

sulphur said:


> Don't digital pedals get sketchy when daisy-chained?
> I know that Ryan @ Dr Scientist warns agianst this with his digital units.
> 
> The only pedal that I got in that I had trouble like this, was a power hungery 2-300 mA modulation effect.
> It wouldn't work until I fed it enough mAs.


It depends. You're correct in that some digital pedals can mysteriously go from dead quiet to "mosquito swarm" noisiness when two or more share the same power supply. However, as power-bricks went up in capacity, and digital pedals came down in current requirements, and as more pedalboards became more stuffed with digital pedals, the requirement to build in protection against clock-noise spikes on power lines became more incumbent on pedal-makers. I won't say they are all tending to it in every digital pedal, but it is more common these days. And, given how hard it is to explain to a lot of users, one would be a fool NOT to include some power-line noise-immunity.


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## cbg1 (Mar 27, 2012)

i had a friend with a digitech harmony pedal.......his power supply gave out on him.......it would not work with any other power supply......he ordererd a new one and all was good.

if you are close to a store that deals in digitech and stocks power supply's you can probably check your pedal out there


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## mhammer (Nov 30, 2007)

I recently had an issue with the PSU that came with my Line 6 M5. I had loaned the unit to a buddy, and after he returned it, it simply would not boot completely, getting stuck somewhere, and leaving me with a functioning-but-unchanging display. So, not "dead", but a glassy-eyed zombie-like stare. The PSU wasable to successfully power analog pedals, but there was a symptomatic whne in the background. I brought the M5 to a local store and asked if they had a known good PSU they could try with the unit so I could tell if the issue was the pedal or the PSU. They did, and the M5 powered up fine. I bought a new supply from them, and all is well.

Bottom line: Switching PSUs like the one that blew, and the VS 1-Spot, and so many others, are pleasingly small and light for the power they provide, but are electronically fragile, with more components, hence more things that can go wrong, in ways that fill up the space between working perfectly and completely dead.


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## Adcandour (Apr 21, 2013)

toby2 said:


> Contact Erikson in Quebec and ask them what their repair policy is like for this sort of thing .


I'll go through the rest of this thread, and then go this route if there's nothing else I can do. Thanks.

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cbg1 said:


> i had a friend with a digitech harmony pedal.......his power supply gave out on him.......it would not work with any other power supply......he ordererd a new one and all was good.
> 
> if you are close to a store that deals in digitech and stocks power supply's you can probably check your pedal out there


Not a bad idea at all. thanks.


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