DD5 no more WET signal?/?

bufferz · February 02, 2013, 08:00:45 PM

Hey guys,

all I did was swap the led and now i have no wet signal. anybody have any suggestions as to where to look?

bufferz · February 04, 2013, 10:30:52 AM

bump,

antone familiar with this circuit that has an ideaa of where to look regarding the wet signal?
interestingly, i can hear how the pedal changes my tone when engaged, however, there are no repeats.

gcme93 · February 04, 2013, 10:42:09 AM

did you put the LED in the right way around? Hope this doesn't sound patronising, everyone makes mistakes, or it could be something you're not aware of (it doesn't seem immediately obvious that an LED should have a positive and a negative side)

bufferz · February 04, 2013, 12:47:12 PM

Yes, I did.
It lights up when effect is on.
Although, the LED should not effect the circuit at all as it is just an on/off indicator - so it really wouldnt matter if it were wrong.
I must have pulled a wire or something, but I cant find the issue. Does anybody know where the wet signal is located on this unit?

cheers

gcme93 · February 04, 2013, 01:21:30 PM

sorry I'm not familiar with the circuit, I thought the LED was in the signal path

bufferz · February 05, 2013, 10:33:48 PM

Bump for help on this

bufferz · February 05, 2013, 10:43:26 PM

Does anyone know where the switching get is on the dd5 and how I could measure if it's operational?

bufferz · February 06, 2013, 12:16:07 PM

I found this:

"Switching on all Boss pedals is electronic. They generally use field-effect transistors (FETs) to do this. When an appropriate voltage is applied to one of the pins of the FET, the other two pins behave as if it is a very low resistance piece of wire. Not as low as actual wire, mind you, but low enough. When the voltage is removed, those same two pins now have a very high resistance between them, similar to, though obviously not as high as, a broken wire.

The FETs in the pedal are "actuated" by what is called a "flip-flop" circuit. This is a circuit that has two outputs, each of which can either go nowhere (as is the case in flangers, chorus, and delay pedals) or to a specific FET. When one of those outputs is "high" (applying a voltage), the other is "low" (no voltage). A momentary switch flips it from one being high and the other low, to the reverse state. Each momentary switch action causes it to flip and flop, such that when one or some FETs are in a low-resistance state, the other/s are in a high resistance state.

Now, the LED is turned on by the same voltage and flip-flop output that turns on the appropriate FET. So, it would seem that there is nothing wrong with the flip-flop circuit itself. Rather, the problem would seem to stem from the flip-flop not making the FETs change state. That could be because of something wrong with the FETs, or something amiss in between the flip-flop and the FETs."

I switched from a 3mm red led to a 5mm blue led, does anyone know if this change in led could have adjusted the current which then cause the fet to not switch the effect on?

Paul Marossy · February 06, 2013, 12:38:22 PM

Quote from: bufferz on February 06, 2013, 12:16:07 PM
I switched from a 3mm red led to a 5mm blue led, does anyone know if this change in led could have adjusted the current which then cause the fet to not switch the effect on?

That would be my guess.

bufferz · February 06, 2013, 10:48:20 PM

Switched the led back, same problem. Uneffected signal passes when pedal is on or off, can hear some coloration in the tone, but no repeats.

bufferz · February 07, 2013, 02:11:57 PM

Here are some pics

slacker · February 07, 2013, 03:05:06 PM

Have you tried both jacks?

Assuming yours is the same as this one http://music-electronics-forum.com/attachments/9484d1275707306-dd5.jpg check to see if you have signal on pins 1 and 7 of IC3, you should get something there in bypass and effect. If you get signals there then with the effect on (LED is on) do you have any delayed signal at the emitters of Q7 and Q8? If you have then check all the connections to the E-Level pot.
If you don't get any signal on Q7 and Q8 then it could get tricky very quickly because there could be a problem with the digital side of things.

Paul Marossy · February 07, 2013, 03:27:36 PM

Hmm... hopefully one of those digital chips didn't get killed from a static discharge or something.

I see this one come up a lot over the years. People change the LED on their Boss pedal and then it doesn't work anymore. I don't know why it happens. Hope you can figure it out.

bufferz · February 19, 2013, 06:23:47 PM

Quote from: slacker on February 07, 2013, 03:05:06 PM
Have you tried both jacks?

Assuming yours is the same as this one http://music-electronics-forum.com/attachments/9484d1275707306-dd5.jpg check to see if you have signal on pins 1 and 7 of IC3, you should get something there in bypass and effect. If you get signals there then with the effect on (LED is on) do you have any delayed signal at the emitters of Q7 and Q8? If you have then check all the connections to the E-Level pot.
If you don't get any signal on Q7 and Q8 then it could get tricky very quickly because there could be a problem with the digital side of things.

I did try both Jacks, I have purchased a multimeter, what setting should i have it on to test the emitters of Q7 and Q8?

slacker · February 20, 2013, 04:32:23 PM

You don't need a multimeter, yet. To check for signal you need an audio probe, there's details of how to make and use one here http://www.diystompboxes.com/wiki/index.php?title=Debugging, you basically play some sound into the pedal and then use the probe to see if you can hear signal in various places around the circuit.

Paul Marossy · February 20, 2013, 04:39:49 PM

Audio probes are a great tool to help figure out where the problem is, if it's something that is in the signal path. Mine has saved my sanity more than once.

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DD5 no more WET signal?/?