What is this stuff on this board?

[anotherjim]

Roland/Boss seem to have been good for supplying power bricks that are +9v centre-negative on a 2.1 plug for other non-pedal gear. I have an SP404 sampler and a Vk8m organ module that came with such 9v SMPS. Very handy this commonality is, but it does suggest they would protect against a centre-positive supply if only with a shorting diode - it's not like it costs much to do.

[Locrian99]

Roland/Boss seem to have been good for supplying power bricks that are +9v centre-negative on a 2.1 plug for other non-pedal gear. I have an SP404 sampler and a Vk8m organ module that came with such 9v SMPS. Very handy this commonality is, but it does suggest they would protect against a centre-positive supply if only with a shorting diode - it's not like it costs much to do.

I found in synthxl they have the service manuals for many boss products (of course not this one!).   But they have schematics and of the ones I've looked at the all have the protection diode.  It does loom like the power circuits are a bit different though as this thing has some sleep mode function they had to add to comply with California law apparently.   Which is why it has a different type of switch than the regular multi effects as I understand.    As I said I have the new switch on its way, so I'm going to put this on hold I think until the switch arrives...likely a few weeks from Europe to US.   Swap that out then check voltage at that diode before I remove and replace.   Thanks for the responses, hate to see this thing end up in the landfill if it can be fixed without dumping a ton of cash into it.   

[duck_arse]

Edit - still trying to dig around but found info that "most" boss pedals have a polarity protection diode.

lacking any new names for concrete blocks, I'll learn this for today. mention of sleep functions is a new spanner thrown in with the sabots.