BOSS RC-2 Fried from wrong PSU

[R.G.]

I suggest you do the necessary test on at least one and perhaps a few "victims" and see what happens. You might have time to glom it on before volume production. A lot depends on how much energy is stored in the output filter caps and whether the peak currents can fry the elements in the converter in reverse. You might also want to call the supplier of the converter IC and see if they have some words of wisdom. If they're not familiar with this as a possible failure syndrome, it tells you their application engineers don't have the right level of experience.

[J M Fahey]

I wouldn't be surprised if they hadn't included such diode "on chip" *or* suggested using it in the datasheet.
Old Stone Age 78xx regulators already suggested that.

[R.G.]

You'd think so, wouldn't you? It surprised *me* to not see it, but it's uncommon to find one. It may well be mentioned in the datasheets or app notes, but not prominently.

The stone age 78xx regulators did mention it in datasheets and app notes, but they are commonly used without a "shorted input" protection diode, too.

Protection devices for odd situations is one situation where Muntzing is not going to make a better product. Protection against uncommon circumstances is utter wasted effort - until that situation happens. I've never actually used a fire extinguisher on a fire, but I don't think having them sitting around is a waste of money.

[mweetman]

Hi
Had a similar problem with my RC2. I just replaced the switching regulator BD9851, which restored the 3v3 & 1v5 supply. However, it's clear that the Flash memory also got fried when the wrong PSU was plugged in, as the Flash gets hot (even from a battery supply) so unlikely I can fix the unit.
The Flash is in a BGA package, which will be next to impossible to replace. It would also need reprogramming :-(
I'll stick to fixing vintage pedals in future.....
Would appreciate schematics if anyone has them. I reverse engineered the board PSU.
Martin