Need Help Getting An Old Pedal Working Again ...

[kurdt]

Hey,

I've just plugged in an old Boss compressor pedal that has been sitting in a draw for a good ten years or so, only to find it's not working.

I've no experience with the insides of fx pedals, but I can solder, and have wired up a few guitars (thanks to advice from some kind people on here), so I was hopeing it might be something simple I could sort out myself (with a bit of guidance).

When I switch the pedal on, I can still hear the guitar loud and clear, but I can hear a quieter and very distorted guitar sound also. It's like there are two guitars playing the same thing, one clean and one very distorted.

The knobs on the pedal still seem to be working, although it's hard to hear what they're actually doing over the distortion.

I've had a look inside the pedal and can't see any obvious signs of anything being broken or burnt out. The input/output sockets do have a bit of corrosion on the outside of them but I think they're still working ok, as I can still hear the guitar perfectly well when the pedal is turned off.

The one thing I have noticed is that the metal pin inside the socket where you plug the power lead into, is all black ... maybe corroded?. And also when the pedal is turned on, the red LED is very dim compared to the LED on my other Boss pedals.

Is it possibly just not getting enough power due to corrosion in the power socket?

Any advice would be appreciated, cheers

[sumgai]

kurdt,

Did you use the original wallwart power supply? If not, then I have two things for you to check out:

1) Correct voltage

and

2) Polarity.

That last bears explaining.... Boss is famous for using a "reverse" power scheme - the input power jack is often wired to have "negative on the center pin, positive on the outer shell", the reverse of normal practice for nearly everyone else. Even some of Boss's own pedals are normal, comparatively speaking.

If you did use the original supply, then put a meter on it to make sure it's still putting out the correct voltage. They don't often go bad from lack of use, but better to be sure with a quick measurement than to wonder about it, right?

Report back with the results, and if necessary, we'll tackle the next thing in line.

HTH




sumgai

[kurdt]

Hey Sumgai,

Thanks for the reply.

You'll have to bear with me here, when people start talking about voltages and polarity, it all goes a bit over my head.

I've been using a power supply that was recommended for use with Boss pedals, but it's not actually made by Boss.

You can see it if you Click Here

Power supply info ...

"9V DC Regulated Power Supply With Integrated 6-Way Daisy Chain / EPS-426
1330ma (1.33A) 9V DC Regulated Power Supply with integrated 6-way Daisy Chain."

Looking in the CS-3 manual, it says ...

"Power requirement ... 9v dry battery x1, AC adapter (ACA series)
Current draw ... 10mA (9VDC)"

I guess it should be fine with the CS-3 pedal as the same website sells that pedal and also suggests that power supply to use with it.

Unless you think Boss may of used that reverse power scheme in the older CS-3 pedals, and have since changed to the normal type in newer ones?

I've just managed to find an old battery to try powering the pedal with that instead.
I plugged it in and it works perfectly, no distortion and the LED is nice and bright now, but of course I still wanna get it working with a power supply instead.

If it is just a case of putting a new power socket in, will I have to get one from Boss, or are there more readily available generic ones that will fit?

Cheers.

[ashcatlt]

Pretty much anybody who uses that kind of connector on a pedal for DC power uses the "Boss standard". If you had connected the wrong polarity wallwart you would have had nothing at all - no LED, no sound - until either the pedal or the wallwart let out their magic smoke.

You could open up the pedal, connect the wallwart, and measure DC voltage on the inside of the jack.

My completely way out guess is that for one reason or another your supply is coming in very low. This could cause distortion in the compression circuit, and dim LED, and (here's where I go out on a bit of a limb) possibly not allow the transistors which control the bypass scheme to completely open or close or whatever so that they are just halfway open and you're getting a mix of the clean bypass signal with the distorted comp signal. Maybe?

Corrosion on the power jack could cause this. It should be sort of self cleaning. Take that daisy chain thing (not connected to the wallwart, we want no power for this) and jack it in and out a few times. Maybe very gently push at an angle to force a bit more contact pressure. Don't break it loose from the PCB! You could help this along by first spraying a little electronic contact cleaner, some denatured alcohol, or even isopropyl (rubbing) alcohol.

HTH

[JohnH]

Its good news - if it works on battery, there cant be anything much complicated wrong inside. Its either the jack or the power supply.

How about wire the power supply directly to the battery connector and see if it works? centre is negative, outer is positive, (for no good reason snce the days when available PNP transistors tended to need a circuit with a positive ground - which is just my guess as to why this became the convention)

John

[ashcatlt]

I'm pretty sure Boss did this specifically so that they could sell proprietary power supplies.

There is no other good reason.

It goes along with that "polarity protection" diode reverse biased across the rails. If you connect the wrong polarity, the circuit is protected for a bit while the power supply and the diode battle to the death. If the diode loses (it always does!) then everything else in the pedal which is polarity sensitive starts popping.

When you send it back for warranty service they can say "You didn't use an approved Boss brand power supply, and we have the exploded diode to prove it."

[lunaalta]

Have you had the opportunity to check the power supply with another Boss pedal?
That would narrow things down a bit.
As would trying another power supply with your CS - 3. Your local friendly dealer or a friend, perhaps.

[kurdt]

Hi,

Sorry for the late reply, I've been bogged down with work.

So, the pedal is still not working with the power supply, but I think I've realised why.

Turns out pre 1997 BOSS pedals need an ACA power supply, and my other newer BOSS pedals need a PSA supply, which is why they all work fine with the power supply I'm using, but it's not enough juice for the CS-3.

So is there any way to modifiy the CS-3 to work with a PSA supply? ... or is it not worth the hassle?

Cheers, Martyn.

[ashcatlt]

Apparently if you daisy chain the power off of a PSA adapter to both an ACA anda PSA pedal and also run your audio through both (doesn't matter which comes first), both will work just fine.

This link talks about the difference and shows a way to mod your ACA pedal. I think just shorting the two wires together would have to be easier.

[kurdt]

Hey Ash,

Thanks a lot for that link.

I've just tried putting the CS-3 on my pedal board hooked up to all the other pedals, and you're right, it works perfectly! ... nice clear sound, and the LED is on full

I think I might go a head and try the mod anyway tho, it seems simple enough and it'll be handy if I ever wanna use the CS-3 on its own.

Thanks for all the advice guys, I appreciate it.