BOSS DD-3

[TIMBO]

Hi guy's, Got a DD-3 that has a foot sw. that has lost its click. This pedal does not get much of a workout so i don't know what the problem is?? When the pedal is depressed the led comes on but when the pedal is released the led goes out, the switch does not seem to click. I had a look at the sw. and pulled it apart but nothing look out of place and i could not see how the sw. would function anyway. Thanks

[sluckey]

That switch is a momentary pushbutton. It does not latch in the on position. When you step on the switch, the contacts make. When you step off, the contacts open. The fact that the LED turns on while you are stepping on the switch means the switch is OK.

You have a circuit problem, maybe IC7.

http://music-electronics-forum.com/attachments/6881d1257549797-dd-3a_service_notes.pdf

[six_eight]

Looks like they are using a CD4066 (IC3) as a flip flop for the LED.  You can try replacing that chip.  They are inexpensive and you can probably find one at RadioShack.

edit:

I'm sorry.  IC3 is an analog switch.  IC4 is a 74HC00 NAND Gate that is functioning as a flip flop, so that is probably the chip that you need to replace if the pedal will not stay in an ON state.  Actually, it could be either of those chips, so if you place an order for one, you might as well save yourself the shipping on a 50 cent part and order both at the same time.

[six_eight]

One question though...

You do realize that the DD3 has a hold feature and that when you are in hold mode, the "ON" state is momentary, meaning that it's only on when you're actually stepping on the footswitch?

[TIMBO]

Thanks 6 8, I kinda shelved it as i was going to take it to a repair shop but at the moment i bussy with work and my new build,so i'll put it back together and suss it out. I was originally thinking that i may have blown something when i plugged in the wrong wall wart  Thanks

[six_eight]

Doh!  That's a good bit of info to have though.

Does the pedal still pass unaffected signal?  Usually it's the op amps that go first if you use a power supply with the wrong polarity.  The 4066 and all of the components in the dry signal path are on an unregulated power supply.  So those would be the only components that you could have damaged by using the wrong power supply.  Except, of course, the 5v regulator.  The delay circuit and the 74HC00 are on a regulated 5v supply.  That means those components would not be damaged if you used the wrong power supply because the voltage regulator would have protected them.  So....

If you are still getting dry signal in bypass there are only two components you would need to replace due to reverse polarity:  The CD4066 and/or the 78L05 voltage regulator.

[TIMBO]

OK I"M AN IDIOT. Thought i better put this think back together before i send it off to be repaired. Had to get a new battery for the MM and stuck in the delay for another try and SNAP it works  I'm either an IDIOT or a ELECTRONICS HEALER, praise the lord or it just needed a NEW battery and wall wart and not left on HOLD and a better guitarist.Thanks 

[John]

and a better guitarist.

ALL my pedals need that!