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boss dd-3 hums, advice?

Started by joerick, April 25, 2008, 09:56:35 AM

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joerick

I have an old Boss DD-3 (I think it's a first revision, with the huge Roland IC on the PCB), and it's great to play with, but it hums pretty loudly. Now as I see it, short of getting a new one(!), these are my options:
1. Would it be safe to assume the hum is coming from my power supply? None of my other pedals hum with this supply, but maybe they contain power smoothing circuitry? If so, could I put in some LC configuration in a box before the input jack?

9V in _())))____________ 9V out
               |
               |
             __|__
             _____
               |
               |
0V   __________|________


2. Failing that, since the DD-3 can be used with two outputs (one dry, one wet), how easy would it be to make a box that is effectively a FX loop with dry/wet control?

Thanks for any help in advance!
Joe

crystaltech56

This is gonna sound dumb but......some times your easiest fixes will be what you need. Have you cleaned the connections: power supply, input and output signal jacks? Dead serious, since you say it's old. the technique consists of removing all three jacks from the housing (you probably have to remove the board too, I assume you have a clean bench where you can do delicate work) and use what use to be called a "typewriter eraser" to clean all contact points. Also clean the point where the power supply enters the board. When I say clean, I mean rub off all solder flux with the eraser( sometimes can also use ordinary pencil eraser) then use acid brush to wipe away residue with rubbing alcohol. Clean your input and output connector jacks as well, then put new flux(micro amount!) and reflow solder on it carefully. Old solder flux can breakdown and become conductive, and corrosion can grow around all three connectors causing ground loops and internal oscilations from out of no where. At the same time clean and corrosion from all three areas. Next step would be to clean large deposits of flux on pc board. Next step would be replacing first capacitor in Power supply input line(not in the plug in power supply, on the device board itself). Remember, work slowly and carefully. Crystaltech56