BOSS DD3 - LOUD HUM - No Effect - Powers On (SOLVED)

[aryasridhar]

Hello All,

I just got a DD3 and it has a LOUD hum and there's no effect, I tried using a regular wall adapter, and also tried with a battery, but it does not power on with a battery, does power on with the wall adapter, it is a regulated 9v adapter.

I cleaned up all the pots and the jacks with CRC-226, electrical contact cleaner, and have left it home for it to be absorbed and cleaned.

I also replaced the 100uf 16v filter cap next to the power supply input, it did measure right, but did it just for the sake of it with a nichicon capacitor, same value.

Also just downloaded the schematic of the DD2/3 to trace the signal once I am back home.

I am wondering, what could be the issue? the power LED sometimes is on and sometimes off, it just has a mind of its own it looks like? could it be the reverse polarity protection diode or maybe the voltage regulator?

This is a used unit i bought from someone very cheap, I did not see a single soldering/desoldering attempt anywhere on the board, so am pretty sure this has not been fiddled around with, I am unsure if the guy using the unit before me blew up the power section either. I can clearly see no repair attempts were made on this unit.

I am assuming, this could be something related to power, or grounding or the mechanical components not being in good shape, however still looking for some answers please.

This is a Made in Taiwan unit!!

Would appreciate any inputs please.

[GibsonGM]

How about the jack connections to the enclosure?  Sure the PCB is connected to the enclosure as well? (check continuity).

Next: is there a protection diode, and is it blown?

[duck_arse]

+1 on gibbo's diode. any scorch marks? D009 and IC9.

[aryasridhar]

How about the jack connections to the enclosure?  Sure the PCB is connected to the enclosure as well? (check continuity).

Next: is there a protection diode, and is it blown?

Right after I opened the box, there were two lugs from the PCB connecting to the Enclosure (screws), I see the jack connections were also intact, however, I did sprayed them with a contact cleaner just to be sure of a good contact.

I did check for D9 (I have to look again to see if it has issues or burnt marks) and C1, to see any major issues/or burns, but will check again once I am in front of it..I replaced C1 with a good capacitor. it was a 100uf/16v cap.

I will check and post here as soon as i see the board again

[aryasridhar]

+1 on gibbo's diode. any scorch marks? D009 and IC9.

Yeah, I have to go back to the pedal and check both, I will post as soon as I have checked it.

[aryasridhar]

OK, I just checked now, and I do not see D9 or any of the other IC's or the electrolytic capacitors bulge or blown up!!

I read somewhere to replace all the 10uf and the 100uf caps, would that help?

[aryasridhar]

Spent an hour, replacing all the 10uf and C1, with some Nichicon caps....put it all together, boom, works really well, not a bit of noise from the unit...infact loving it!!

[duck_arse]

a mystery, but well sorted.

[aryasridhar]

a mystery, but well sorted.

Yeah, it works really well now, I now have two delays for under 30USD, A Joyo Analog delay that i love, so I plan to use both on my board, the Boss sounds great for Slapback/Short delay settings, and the JOYO for lead stuff!!