Boss DS-1 no sound when engaged.

[MissionBrown]

Bought a 2nd hand DS-1 yesterday from a 2nd hand dealer in town.
Sure it looks nice and spanking new but it only passes sound when bypassed.

Wondering if anyone has come across this problem before.

It looks like someone might've taken a soldering iron to it, but only where the wires from the switch meet the board.

I saw a post here http://www.muzique.com/news/fat-mod-for-the-boss-ds-1/ that mentions two resistor changes which could've caused it.
Didn't notice anything out of place however. If it's an easy fix I'll keep it, if not I'll just take the sucker back.

[GibsonGM]

That could be a good platform for modding, and the enclosure might be useful if it doesn't work.  Depends on what you paid for it, I'd say.
It's a common problem.  Often, the microswitches fail in Boss, Digitech (etc.) pedals.  I'd suspect that might be the case...sounds like someone got in there and tried to fix it, tho.  You can get a schematic online and try to work it out - they might have put the wires back backwards, or the switch might still be dead.  Then of course it could be the FETs that do the switching....hard to say until you start probing around in there!!  If you like DIY, here's a chance to dig in, lol.
I think the guy should have tested it out before putting it up for sale. 

[BAARON]

There's always the possibility of a dead park (op-amp, treble boost transistor, etc).  Another thing that could be happening is a shorted clipping diode.  That would certainly mute it when the pedal is activated!

[Paul Marossy]

It's a common problem.  Often, the microswitches fail in Boss, Digitech (etc.) pedals. 

Could be. But I've heard a lot of people say "I modded my pedal and now it doesn't work" before. For the few of those that I have fixed for other people, it was due to simple stuff like a cold solder joint or a solder bridge.

[Quackzed]

i'd start with the mechanical stuff, jacks, switch, wires, basically anything that can move... can break. think murphys law.
plug it in,set it up into your amp ,then ...
-wiggle the wires inside gently, wiggle the jacks/1/4' plugs, wiggle the switch wires.. look for rust, dull grey solder connections,loose wirees , anything out of the ordinary...rotate the pots back/forth, try to get it to pass some sound and give you an idea of where the issue is..
-battery wires often get damaged freyed from replacing batterys..
-if someone plugged a positive tip power jack, they could have killed the protection diode, search 'reverse polarity protection'...
----the switch is a good bet on boss pedals, try stomping it on/off very fast for a while ,see if you can get it working...
-look to see if anyone spilled anything into it, dried sticky anything?
if all else fails you can search 'what to do when it's not working' faq ...
90% of the time its mechanical part failure.
-btw there's a really good pdf on the ds-1, mods etc, you can do once you get it working..."build your own ds-1"  so don't give up!
-i can personally recommend the mij mods. 

[MissionBrown]

That could be a good platform for modding...  If you like DIY, here's a chance to dig in, lol.
I think the guy should have tested it out before putting it up for sale. 

After all that encouragement I think I'll hang onto it.
Do I like DIY? Heck yeah!
I'm sure I can get it going from my big stash of parts.

The only testing that I think was done when the "owner" pawned it was to see if the red light came on.
Not exactly geniuses at this particular chain of 2nd hand stores.

The version of the pedal I have has the NJM3404AL, will that make a difference to what mod I should try?
I read somewhere that opa2134's work nicely in the DS-1. I have a couple laying about and will give them a go if anyone recommends it(I know I'll need to make up a board to fit 'em).

Does it still distort if the clipping diodes are removed from the circuit altogether?

[Paul Marossy]

Don't have an answer for you on the clipping diodes, but one other thing that happens a lot when people mod pedals is that copper on the PCB breaks sometimes which results in no connection being made. It can be very hard to see sometimes. Best way to check for that is with a continuity checker around any areas that look like they were worked on after the pedal was built.

[MissionBrown]

Can't believe I missed this last night, D1 had  split in two!
I replaced it with a 1n4004 as I didn't have any other rectifier diodes on hand.
Still not getting a sound out of effect mode, is there anytthing else that would definitely blow along with D1?

Edit*

Not sure where I'd find info for the reference voltages I need to look out for.
One thing I noticed is the IC is pretty warm and in the past in my experience indicates that the chip is dead.
Would you kind folk agree?

[MissionBrown]

All fixed!

Pulled out the old IC and made my own chip adapter and popped in an opa2134 that happened to be within arms reach.
Now its time to do some mods.  As it is at the moment I'm not a fan of the crazy distortion and scooped mids (I play dirty surf style guitar mostly).

Anyway am happy that it was a simple fix.

Thanks for the help guys!

[BAARON]

Surf?  You might like this mod then, as it makes the pedal much less METAL and closer to a raunchy overdrive: http://www.muzique.com/news/fat-mod-for-the-boss-ds-1/

You might also consider some softer clipping diodes, like putting a Germanium diode or two in series with your clipping diodes to round out the waveform a bit and raise the forward voltage.

The OPA2134 should be a great opamp for that circuit, as its rail clipping is decidedly nicer than many op-amps.

If you remove the clipping diodes entirely the circuit will still distort, yes, because the op-amp distorts.  However, it will also be so loud that it might push the output buffers into distortion too, and that's not a good sound.  If you want a cleaner sound I would recommend using clipping diodes (or a combination thereof) with a higher forward voltage - somewhere in the 2v range will make it cleaner and less compressed while still staying inside the safe zone for the buffers in the DS1.

[Quackzed]

http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf
glad you got it up and running, sounds like someone plugged a positive tip wall wart into it and *poof* 

...you could try replacing d4 and d5 each with red led's ,that should open it up quite a bit. make it less distorted and less compressed...
there are a ton of mods for this one, truly a distortion 'classic'. I did the mij mods from the pdf, so mine has a bit more open sound now, and a bit more low end oomph.

[Paul Marossy]

Cool, glad you got it fixed. 

[Electron Tornado]

Here's some other mods worth trying. I've done these to my DS-1 and it sounds much better than stock.

http://www.robertkeeley.com/audio6l6/dstech.html

[MissionBrown]

Here's a wee photo of the former D1.


I'll definitely be doing some of the mods suggested, probably a hybrid of the Fat and MIJ mods, there's also a gated mod from Casper electronics which
gives some self oscillation controlled by a gate. Sounds sort of 8 bit.  http://www.casperelectronics.com/finished-pieces/boss-ds-1/
My parts box is littered with clipping candidates, has anyone tried using leaky germanium transistors as clipping diodes?
I think I read that on AMZ, seems a better solution than sending them to landfill at any rate.

[MissionBrown]

I've done a few mods and the pedal is sounding really good now!

I've done a variant of the all seeing eye with the other diode a 1n4004(Socketed for easy experiments later).
The fat mod is quite nice and I've added a switch between that and stock values.
My 3rd mod is one that flattens the midrange, again switchable back to stock.

The clipping diodes make the biggest difference even the stock gain level is nice to the ears now.
That said switching the gain stages changes the frequency response of the tone control in a pleasant way.
It seem that the centre frequency shifts up or down depending on which settlings the switches are on.

Turned a busted cheap ugly (To my ears) sounding distortion into a cool little drive that has won a home on my board.

Thanks to everyone for the suggestions.
Cheers
Mission Brown.

[mikemaddux]

[Paul Marossy]

Yeah, and it looks burnt. I wonder how that happened?