Boss OS-2 problem - please help!

[Fuzzy Lumpkins]

Firstly, I'm a long(-ish)time lurker and frequently reference this forum when considering new purchases... so thanks.

Now down to business.

Please check this out:
[youtube]http://www.youtube.com/watch?v=WqR2YIq3H0U[/youtube]

I've had the Boss OS-2 for nearly 20 years and as far back as I can recall I've had this problem, which is why I've only recently picked it up again.

The problem, as the video demonstrates, is that the sound rather randomly cuts out completely and sometimes drops in volume. Giving it anything from a slight tap to a few moderate bangs on a surface fixes the problem... but it also causes the problem; i.e. the pedal's working fine, has a light nudge and cuts out. There are other times when banging and shaking the pedal causes no problems whatsoever.

A few years ago I brought a guitar to a repair shop to have its electronics fixed and also brought along the OS-2. The guy claimed to have fixed the guitar problem but couldn't find any fault with the pedal. As he didn't charge me for his work on the pedal I happily took his word for it. Turns out, of course, that he was wrong and the problem with the pedal remains... and he didn't really even fix my guitar!

Anyway... What I want to know is if anyone knows: 1) what's causing the problem; and 2) how I can fix it.

I'm relatively inexperienced with electronics (e.g. I've diagnosed and fixed a laptop screen problem by replacing the backlight, so I can follow basic instructions) but I'd rather try to fix it myself than risk wasting my time again by bringing it to an 'expert'.

Thanks in advance for any help you can provide.

[Schlatte]

my wild guesses: a) broken input/output/dc jack or b) broken volume pot
since all the parts in there are pcb mounted, and the bypass is buffered- it has to be a hardware problem imo.

[Fuzzy Lumpkins]

Thanks Schlatte.

Do you think it's possible for me to open up the OS-2, look at the pcb and SEE the problem? Or would I have to somehow test each part to establish the source of the problem?


Thanks again.

[Schlatte]

ok from looking at the video again I can say that it's not the dc jack. otherwise the led wouldn't light up... and it's probably also not the volume pot- otherwise the volume drop would only be there when the distortion is engaged... so my wild guess would be input/output jack... (or there is something wrong with the buffered bypass switching but that would be kinda weird)... have you tried shaking it to hear if there are some bits flying around in it? and I suppose you don't have warranty anymore, so just open it up and check the jacks...

[Fuzzy Lumpkins]

I'll check the input/output jacks tomorrow.

Thanks!

[Adoom]

My DF-2 had a massive volume drop and various sound issues until I gave it the power it needed. I was plugging into a regular 'ol 9v thing, but older Boss pedals require a little extra juice in some regard. I'd look up the specifics for you, but I'm on my phone currently. Maybe use a proper Boss adaptor or a power supply that feeds it the oomph older Boss's apparently hunger for.

[Fuzzy Lumpkins]

@Schalatte (and anyone else who may be interested)

I opened it up and took everything out of the pedal casing to check the input and output jacks, and I couldn't SEE any problem (e.g. bad soldering, loose wires or rust).

While in this state I connected the pedal to a 9v battery to test the unit and there was no sound except for a loud hum. I suspected this may be due to it being out of its metal casing - although I have no idea why/how this would affect anything - so I put it back inside the casing and it's back to its usual self; i.e. sometimes a bump causes the sound to cut out and it needs another bump or three to return to normal.

Any more ideas what could be causing the sound cutting out problem? And also, is it normal for the unit to not function when it's not in its metal casing.

My DF-2 had a massive volume drop and various sound issues until I gave it the power it needed. I was plugging into a regular 'ol 9v thing, but older Boss pedals require a little extra juice in some regard.

Thanks for the suggestion... but isn't it a bit risky to give an effect more power than its manual suggests? And just so you know, I've used the pedal with various adapters and 9v batteries and the problem's always been there.

[bob the r0bot]

I have nothing to contribute to this thread but, I love the Power Puff Girls and your avatar makes me happy.

[Fuzzy Lumpkins]

I have nothing to contribute to this thread but, I love the Power Puff Girls and your avatar makes me happy.

[Adoom]

http://www.mylespaul.com/forums/pedals/ ... ost1400635

That's got the details, and from my own experience, stands to be true. Older boss pedals (like my DF-2, and if you've had it 20 years, your OS-2) have particular power requirements. They're hungerier beasts, wanting 12v, not 9. This is just a suggestion though, I'm not sure, but it may help!

[Seiche]

the in and out jacks are pcb mount aren't they? over the years and abuse the solder gets cracky from movement. can you maybe try to reflow them with an iron?

[Fuzzy Lumpkins]

@Adoom

Thanks for the link. My pedal actually says to use a "PSA" adapter and I encounter the same audio problems when I use 9v batteries. Could giving the pedal 12v via an adapter to see if it's a power issue potentially damage the pedal?

@Seiche

The jacks aren't mounted to the PCB but connected via wires (e.g. http://img.photobucket.com/albums/v314/guitarslinger213/amps/P1010043.jpg and http://havaiavas.files.wordpress.com/2009/03/img_0008.jpg?w=450&h=337).

By "reflow" do you mean heat the solder so it flows and resets? And given that the jacks aren't PCB mounted, do you think it's worth reflowing them?

[Seiche]

By "reflow" do you mean heat the solder so it flows and resets? And given that the jacks aren't PCB mounted, do you think it's worth reflowing them?

yes and maybe. Sometimes the wires can come loose over time when a solder spot isn't done perfectly (the lug on the jack not completely filled with solder).
That can be determined by looking at the solder spots. Or there is a break in a wire somewhere.

[Astricii]

So, it didn't work when it was out of the case, and has intermitted function when in it's case? sounds like the board is grounding out somewhere, try putting some foam bits above and below the pcb when putting it back together and see if the problem gets better or worse. if it needs a ground connection you'll have no volume, if it is accidentally grounding out then that should fix the problem.

[Adoom]

@Adoom

Thanks for the link. My pedal actually says to use a "PSA" adapter and I encounter the same audio problems when I use 9v batteries. Could giving the pedal 12v via an adapter to see if it's a power issue potentially damage the pedal?

@Seiche

The jacks aren't mounted to the PCB but connected via wires (e.g. http://img.photobucket.com/albums/v314/guitarslinger213/amps/P1010043.jpg and http://havaiavas.files.wordpress.com/2009/03/img_0008.jpg?w=450&h=337).

By "reflow" do you mean heat the solder so it flows and resets? And given that the jacks aren't PCB mounted, do you think it's worth reflowing them?

Hm. Shit man, I have no idea. And I'd hate to have you fry your device over my middling bullshit.

I used a Boss adaptor, official style, and that seemed to quell the problem, so if you got one lying about?