Fixing a Boss DS-1

Started by AlonL, July 20, 2010, 03:49:57 PM

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AlonL

A few years ago I tried my luck with modding a DS-1 (Keeley mod+all seeing eye, if it matters).
I bested the mod, only to end up connecting the effect to an 9V AC supply, instead of a 9V DC supply, days later  :icon_redface:

Ever since its been sitting in my drawer, and I've finally decided to fix it (or at least do something with the box )
I was told a while back that it only comes down to replacing a single diode that should have acted similar to a fuse, and kept the electric mayhem away from the rest of the circuit.
Although, I do recall the power LED coming on when I connected the supply, and not coming on when I tried to turn the effect on later, after connecting the correct power supply.
So, can anyone please guide me as to what I would need to replace on the board in order to fix my precious effect?

Thanks ahead.

Electron Tornado

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Bad Chizzle

First try replacing that big black diode with the silver stripe. Should be right by the power jack. Then if that Doesn't do it, go through the debug info provided by the last poster above. You may get lucky with the diode thing. It may have burned out, in which case your led would not have lit up after using the correct power supply. Question: what do you use the ac power supply for? Sounds dangerous to keep around your pedals! Just saying.

Hope I've helped!
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AlonL

#3
Well, this isnt quite a matter for debugging, I think.
I know the problem already, and the fact that my pedal is modded is coincidental at most, I guess...
Plus, I reckon that this is a quite common issue :)

@Bad Chizzle - Thanks, I will try. Should I use a specific diode?
And it was used for a Line6 POD xt I had at the time, since then sold.
EDIT: Hey Chizzle, could you help me out a little more by directing me to the right diode?
I couldnt see anything fitting your description by the power jack :(

EDIT2: I found an image of the board at instructables -
http://www.instructables.com/image/F1M1FEYFSSIQGOY/New-Components-pt1.jpg
and this is from the keeley site
http://www.robertkeeley.com/audio6l6/dsback.jpg
As far as I can tell, the first diode that traces to the power jack is D2, could this be the one?

Bad Chizzle

1n4001 is the diode you want to use. I went back and checked for you, and found it's used in this way often. Good luck!
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Electron Tornado

If the 1n4001 diode in the power supply section was burned out, replace it, but even with it removed completely, the pedal should still work as long as nothing else is bad (even the LED). That diode is not your only problem. I repaired a DS-1 that had suffered a similar fate as yours. That particular diode had actually detonated and was in two peices, with one lead turned 90 degrees from its original position. It would pass signal in bypass mode, but not when the effect was engaged, although the indicator LED would light up. The real (and fortunately the only) problem was that one half of the op amp had also been damaged.

The schematic for the DS-1 should be easy to find on the web. Then go check out that link I posted earlier.  :icon_wink:
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Bad Chizzle

You know, after reading this last post I'm gonna have to agree. Sorry, I was thinking in terms of the way I use them and not the way most pro pedals are set up. My bad!
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Bad Chizzle

I use mine in series with power supply, while yours is probly reversed and from + to ground.
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DiamondDog

Quote from: AlonL on July 20, 2010, 05:15:30 PM
Well, this isnt quite a matter for debugging, I think.

Debugging means investigating something that is not working as it should. That has been modified or not is neither here nor there.

Quote from: AlonL on July 20, 2010, 05:15:30 PM
I know the problem already, and the fact that my pedal is modded is coincidental at most, I guess...

No, you know how the problem is manifesting itself- but do you know the solution? "It's not working" doesn't count as identifying the problem.

It really is worthwhile going through the debugging thread and following it through. It's a little bit of self-help that will go a long way in your learning, in setting out what the actual problem is, and in getting help.

(FWIW, I recently resurrected a DD2 that had a dead power diode, and the first transistor had received such a jolt that it was split in two.)
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Bad Chizzle

Wow, split in two! That is a jolt! I had a power diode split like that diagonally. Didn't notice it at first, then one day after giving up on the circuit for a while, I saw it sitting there plain as day! Said to myself( not looking closely enough are you debugging guy!) another lesson learned that I won't soon forget. Some things are obvious, and those are the things I should always look for first. But often these things are just a symptom of something else being wrong. Or a cause for more damage farther down along the path. I have found that the greater my debugging skills get, the more often I build circuits that work right away with no debugging needed, because I now know what to keep an eye out for while in the building process. Nothing can take the place of the skills learned along with the pain and frustration of failure. And nothing takes the place of building patiently with careful steps taken. I realize much of this doesn't apply to this modding situation, but, it may hold a few nuggets that can be useful in the future.

Chuk
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AlonL

#10
First I would like to thank you all for your help.
@DiamondDog, I have no desire to argue over semantics, I apologize, but I will say, and I haven't mentioned this yet,
my original plan was to dump the original circuit and put a TS808 clone circuit in there, but I think its a waste of an original DS-1 board.
So basically the maximum effort I'm willing to put into this repair is replacing the aforementioned diode.
With that, I've read the debugging topic, and though very educating, I find it irrelevant at best to my amount of dedication with repairing this effect.
Will be sure to use that method when debugging future boards, sorry for the misunderstanding.

And I'm sorry if this seems like I'm trying to be spoon-fed the answer here - I'm just not that electronics savvy:
I understand what diode I can use as a replacement, but I don't understand what diode I need to replace.
I've looked at the original 1980's Boss schematics, and they seem somewhat outdated in reference to my board.
What I figured from them, is that I have to replace D3, a diode which is, well, not in the same location on their board schematic as my actual board, so I guess its somewhat unreliable  :icon_rolleyes:
I've posted pictures of the board in my previous replies, and I would very much appreciate if someone could pinpoint the location of said diode on the actual board, thus preventing me from maiming my board ruthlessly somehow  :icon_confused:

Thanks ahead.

EDIT: Alright, sorry for the many changes, but I seem to have located the diode you are referring to (I'm getting better? heh), and a brief check with the multi-meter reveals that it conducts in both ways!
To be honest, I have no idea what this means, I was expecting it not to conduct in either direction  :icon_confused:

AlonL

One last question - is it okay if I use a 1n4007 diode instead of 1n4001?

Electron Tornado

Don't give up on your DS-1 so easily. Think of it this way - what you have in front of you isn't a broken pedal, it's an opportunity to learn.

There are a couple of different schematics around for the DS-1. Check which IC your has and find the schematic with that chip. A look at the schematic should help show where to check for certain voltages. You can also make yourself an audio probe and use that to help find where the problem(s) lies. You say you don't have much knowledge of electronics. Well, here's a chance to remedy that situation.

Read, study, ask questions, learn. The more you learn, the more fun this hobby becomes.
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AlonL

I would love to, but I honestly haven't got the time...
I'll reconsider what I'll do with it after replacing the diode, in case it doesn't work, but I'm taking it one step at a time.
So, is it okay to use a 1n4007 instead of a 1n4001?  :icon_confused:

StereoKills

Yes, a 1n4007 will be fine in the circuit. Only difference is the reverse voltage rating, 1000v vs 50v.
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Bad Chizzle

Wow, big difference in reverse rating!
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