Boss DD-3 version 3 - No output

[aj7877]

Hi,

Just wondering where to start with fixing this pedal. It's a boss DD-3 version 3 . The power light goes on/off when I press the pedal, however, there's no output. There is output from the "direct out" but this signal doesn't have delay on it(I don't think it's suppose to though).

I've checked the jacks and they are fine and I've also tapped the board for dry joints but still nothing.

I'm an electronics tech by trade but have been out of the industry for quite a few years.

Does anyone know where to start?

Also, does anyone have a schematic?

Thanks

[blipler]

Did you bother to google for a schematic? There is one on this forum.

http://music-electronics-forum.com/s...ad.php?t=11424

Sounds like you've got a loose connection to the wet output jack, have you tried going over the output jack solders?

My DD3 crackles in time with the repeat times. Anyone have any ideas on solving that problem?

[aj7877]

Did you bother to google for a schematic? There is one on this forum.

http://music-electronics-forum.com/s...ad.php?t=11424

Sounds like you've got a loose connection to the wet output jack, have you tried going over the output jack solders?

As I said, I've already checked the jacks & yes of course I have searched for a schematic. Thanks but this is the wrong one. This is for a first edition DD-3 not a version 3..

My DD3 crackles in time with the repeat times. Anyone have any ideas on solving that problem?

Crackling is normally caused by dry joints (bad solder connections) or faulty output/amp chips.

[cjlectronics]

Have you checked power supply voltages?

Check for +9v at pin 14 of the 4066 (IC3)
Check for +5v at pin 14 of the 74HC00 (IC4)
Check for +4.5v at pin 3 of IC1 or C46

Reply back with your results and we'll go from there.

CJ
http://www.cjlectronics.com

[aj7877]

Have you checked power supply voltages?

Thanks for your help. Here's my measurements.

Check for +9v at pin 14 of the 4066 (IC3)

I only have +5.7V here.
Doesn't matter if the effect is turned on or off i.e. led on/off

Check for +5v at pin 14 of the 74HC00 (IC4)

Yes I have +5V here with effect on or off

Check for +4.5v at pin 3 of IC1 or C46

Only get +0.73V here.

[cjlectronics]

You have a short on the +9v net. Check C1, C11, and IC2 (NE570). If IC2 or the 4066 are hot replace them. If all of these look OK, then you may need to start cutting traces to isolate the short. Check the components above first.

CJ

[aj7877]

You have a short on the +9v net. Check C1, C11, and IC2 (NE570). If IC2 or the 4066 are hot replace them. If all of these look OK, then you may need to start cutting traces to isolate the short. Check the components above first.

CJ

Thanks for that. Ok I've checked the caps and they seem fine but I changed them anyway.

As for the ICs, in my experience there really isn't an easy way to tell if they're shot. In my previous career as a TV technician, we used to just change them if we suspected them and they were cheap and easy. Any suggestions on how to check easily?

I was thinking about just changing the 4066 anyway since it's cheap and easy to change. Will any 4066 DIL package do?

IC2 - on my pedal, this is a SA571D. I've checked data sheets and the SA571D has a couple of lower specs(like operating temp and max operating voltage) than the NE570 so I guess either chip is fine? This one's surface mount so will be harder to swap. What's the chance of this one being gone?

Thanks again.

[cjlectronics]

Typically, any 4066 with the same fit, form, and function should work. A 571 will work in place of the 570 as well.

You'll need your troubleshooting skills from this point forward.

I would start cutting traces to isolate the short. I would recommend starting near the AC adapter jack. This is a high failure point. Inspect it for shorts. Then work your way down the +9 volt net. With the battery removed, measure the resistance between the +9v and GND. You 'll know you've isolated the short when that resistance value is larger than your initial measurement.


CJ

[petard]

Hi, I have the same problem with my delay no output , the voltages are correct in the IC 4 and 3,except for the IC1 only 0,74v, it is also too hot, what can be the problem? Thank you

[petard]

the problem was in IC1 changed and my delay came back to life, voltage on pin 3 already gives 4.6 v, thanks