Boss DD3 - not working

[fckwit]

I've recently reqired a dd3 which doesnt work.

sometimes when you gvie the unit a shake it makes a kind of sine wave sound and the pitch of this can be changed with the delay pot.

any ideas what the problem could be?

TIA

[geertjacobs]

Does the LED switch on and off if you step on the footswitch?
Are all the modes working bad or is the Hold-mode still working?

Myabe you've already found this in the archive: http://www.8bitsindgenug.net/boss_dd2.png
DD-2 is almost the same as a DD-3.

G.

[geertjacobs]

Check if the zener diode (D6 in the schematic) hasn't been fried. It serves as a safety if someone uses a wrong power supply.

[fckwit]

Does the LED switch on and off if you step on the footswitch?
Are all the modes working bad or is the Hold-mode still working?

Myabe you've already found this in the archive: http://www.8bitsindgenug.net/boss_dd2.png
DD-2 is almost the same as a DD-3.

G.

the LED does switch on and off yes.

no effect can be heard on any of the modes.

when i put my finger on the circuit board it makes a sine wave sound and if i swtich between modes i can hear delay.

i checked D6 and it is fine.

any ideas?

[geertjacobs]

So the power supply and the switching seem to be ok...
Be sure to test with a (matching) power supply because these pedals drain batteries very fast.
Do you hear clean sound or no sound at all?
An audio probe may be useful to follow the soundpath on the pcb and check where things go wrong.

[fckwit]

i hear a clean sound when the effect is on but no delay.

how do i do an audio probe?

[geertjacobs]

If you use the Search function on top of the page (FAQ - SEARCH - MEMBERLIST...) and use "audio AND probe" as search parameters, you'll find the next thread as your second link:
http://www.diystompboxes.com/sboxforum/viewtopic.php?t=33194&start=0&postdays=0&postorder=asc&highlight=audio+probe

There also is a link to a debugging page on top of the page that mentions the audio probe.

G.

[fckwit]

the LED has becoe momentary for some reason now.

any help?

[geertjacobs]

The hold mode is supposed to do that, the other modes not.

I had a problem with a DD-2 where the LED would fade out in the first three modes.
Some wires coming from the mode switch were almost not connected anymore. Check the switch wiring.
There is a logic table on the schematic that helps in checking if the mode switch is working properly.