Loop Station fried power supply

[lowell]

Not sure what kind of power supply is in these but this is the second time I've seen this in 2 days. There is no power to the pedal and there is this micro smd opamp looking thing that is fried on the board. The owner of the pedal admitted to plugging in the wrong adapter. Is this somekind of regulator chip or switch mode supply arrangement? Secondly is it fixable with a regular soldering and tools, and is it worth the effort? Here is a picture of the board and fried component. It is IC7.

[doctor]

There are many devices from several manufacturers having name “Loop Station”.
What the device you have in mind?

[Steve Conner]

Well, given that "Boss RC-20" is clearly visible on the silkscreen...

Should be easy enough to replace, if you don't have experience working with SMDs you'll be screwed sooner or later, so might as well start.

[cjlectronics]

IC 7 is an S-8520E33MC from Sieko. It's a PWM step down regulator. Not sure where to buy one. However, in my experience with Boss pedals... when the wrong power supply is used it fries more than just a regulator. It'll fry main CPU's as well. If you can find a replacement IC I'd try to replace IC7 but if it still doesn't work I would stop there and use the pedal for parts.

CJ

[doctor]

I personally would recommend turning the device on once more, applying correct adapter (9VDC).
Measure voltage at C40 (100uF/16V). If measured voltage will be more 3.3V+5%
(i.e. DC/DC controller’s input and output are shorted), a big chance exist that other chips having
VCC=3.3V may be damaged as well.
If instead 3.3V you measures 0V, you may be lucky that only IC7 (and maybe Q10) are damaged.

In any case it is possible to order needed parts from Roland:
IC7 (S-8520E33MC-BJS-T2) – Roland code 01906156
Q10 (IRF7606) – Roland code 02562867

[lowell]

Dost thow have a schematic for this supply? C40 measures just under 2Vdc.

[doctor]

Send me your e-mail

[R.G.]

I've seen several failures in the Seiko family of PWM step down regulators. They usually use them to get 5V, 3.3V, or less out of a 9V battery. The problem is when they use the cheaper members of the family which have a 10V absolute maximum rating. These are floating on the edge of death with many power supplies, including Boss, and with a fresh 9V alkaline battery. There is a higher voltage rated family that doesn't get used.

As noted earlier, these are used to provide the voltage for other things, like logic chips which fry if the power supply gets over 3.5V or 6V or some such. If the regulator died such a dramatic death, it's quite likely that the logic circuit is gone too. You can try replacing the regulator, but don't expect much. Chances are it's a total loss from the secondary damage.

[RMD]

Can anyone order parts from Roland? I need to get a couple of those 3.3V regulators for my damaged RT-20 pedal, but am not an authorized service center. Do you have phone number and/or address to order the parts from Roland?
Thanks!

[Jazz P Bass]

As far as I know, Roland will sell spare parts to anyone.

[Mick Bailey]

As far as I know, Roland will sell spare parts to anyone.

That's right. Don't know about the US, but here in the UK you just register on their web site, raise a job ticket and they mail you back with the total cost. No need for an account. It helps them (and you) if you get the correct Roland part number from the service manual.

[g1]

Roland part number is in post #5 above.

[Mick Bailey]

Roland part number is in post #5 above.

Now I just need to get a new hat to hide the jackass ears that I've just sprouted........

[g1]

I'd lend you mine but it's in constant use.

[Audiotexan]

lol
I was gonna say similar to g-one, but I've been wearing mine A LOT lately. *sigh*
Eh, well.. he haw, he haw, he haw-lways gets a chance to redeem his self!