Boss DD-6 service notes

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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ryanuk
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Post by ryanuk »

Would anyone have a schematic or service notes for the Boss DD-6.
I bought one over the weekend. Totally dead as described.
No light or sound at all.

Hoping it's just a power problem. Found a post on another forum that suggests it could be the IC6 5v regulator. Will check that first. As well as checking all the power rails are correct.

There are some similarities to the dd7 but feel like im flying on the dark without a schematic.
Can find the dd3, 5 and 7 but not 6.
Does anyone have it?

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mauman
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Post by mauman »

I've seen users on other forums who have gotten support and parts from Roland (owner of Boss). While they might not share a full schematic, they may provide advice and/or parts, it's worth a try. Look for their Product Support/Backstage/Spares Team web page for your country: https://www.roland.com/global/international/

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ryanuk
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Post by ryanuk »

Mauman
Many thanks for the response. I will certainly give that a try. I did approach Roland/Boss for service notes; unsuccessful as expected.
Once I have opportunity I will have a closer look at the unit.
Good tip approaching their technical team. Will certainly try this if needed.
RyanUK

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Post by ryanuk »

So this pedal has been sat around for a few weeks. I finally got around to looking at it in detail.

Its a complex SMD board. Several op amps for the audio. Other ICs for A/D, D/A, DSP, small RAM, and what I assume is a CPU (marked BOSS BO2DD6).

- Unit is dead. No lights at all. No sound. Switch does not engage effect.
- 9v Power is getting in - can measure at the op amps.
- I stumbled over this forum https://markweinguitarlessons.com/forum ... ita.15702/. which suggested blown dc/dc and FET for the 3V3 power rail for the processors.
- This set up is also used in the BOSS OC3 - https://www.diystompboxes.com/smfforum/ ... c=121371.0
https://www.audioservicemanuals.com/b/b ... ice-manual
- Replaced the FET and DC/DC switching IC with suitable replacements. This FIXED the 3V3 rail. But still no light/output

I have 2 theories.

Either the BOSS DD6 processor is damaged which would explain lack of audio/lights - these are both controlled by CPU in newer pedals (OC3, DD7).

Or perhaps it could be the reset/supervisor IC9 marked JPAL, which (I assume) resets the DSP/CPU ICs. Again the OC3 uses a similar set up (see picture). I measure 3.3v at pins 4 and 5 of IC6 in the DD6, but don't know if reset pins are active high or low?? Not sure to the extent the OC3 compares here.

Would anyone be willing to measure these pins 4 and 5 of IC9 on their DD6?
Or could someone interpret the datasheet for this IC https://www.ablic.com/en/doc/datasheet/ ... S801_E.pdf.?
Either would give me a clue as to whether this IC is operating correctly? I would replace on spec but its obsolete and I cant source pin for pin similar replacement.

Any help or other ideas would be appreciated.
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