dead microkorg

[man-009]

i will check. will keep you posted. not sure what i am going to do depending on the outcome. i still may sell it if it works or not. if it's dead, of course for parts.

[Steve Jones]

Microkorgs have no protection diodes on the power input. Using a reversed or incorrect adaptor usually results on surface mount components being literally blown off the circuit board. A very common problem unfortunately that could have been avoided for a few cents per synth.

[man-009]

that sucks. so what is it worth for parts? it is in mint condition? may need to sell it.

[garranimal]

Microkorgs have no protection diodes on the power input. Using a reversed or incorrect adaptor usually results on surface mount components being literally blown off the circuit board. A very common problem unfortunately that could have been avoided for a few cents per synth.

Makes you wonder what other corners were cut. Whatever happened to things built to last? Back in the day product level replacement was a last resort. Now its about the only resort.

[man-009]

man..i hope batteries work? prob dead though....testing monday! wish me luck~

[man-009]

got it all apart..ahh! i see a blown circuit plain as day. i think only IC5 is bad...a voltage regulator? fixable? hope it's the only issue. C17 looks black a bit from the blowout. maybe replace as well? sea pic i posted. i can't seem to find a pic of the microkorg motherboard on the net to see what should be there? great looking synth..but wont turn on.. i can see why! just the two audio in lights will light green then fade. been reading alot on this issue of wrong adapters causing the blowout! let's see if i can get a $30 buy up and running...
http://imageshack.us/photo/my-images/23/tim001r.jpg/

[adhmzaiusz]

there ya go... that part sure went hard. should be fixable, just some patience and perseverance. its hard to tell how bad the damage is to the traces, but you could probably use nail polish remover to expose a new part of the trace, and with some rosin flux and some careful soldering you could probably successfully fix this.

[adhmzaiusz]

part is: s-8520f33mc
description: DC/DC Switching Regulators 3.3V Step-Down PWM

unfortunately digikey and mouser is non-stocked. might take some more digging.

[man-009]

thanks. a bit unsure i am the guy for the repair though! a friend in texas said ..

matt-" You can always bypass burned traces, but given that is the voltage regulator, you'll need some pretty thick wire due to large current requirements. I think the first thing is to ensure that the main CPU board is still functional.You're in luck that the Hitachi H8 CPU doesn't have embedded ROM - that makes it theoretically replaceable. I think the 3.3V supply is a basic switching power supply - there is no magic to the S-8520 except it is matched to the external components. I would try to ensure that the remainder works on an external 3.3V supply. You can always work around the power supply - I don't think there is anything oddball or magical going on with that.There should be a wire from the power supply to motherboard (pg 5 of schematic - 3.3v digital.). All that P/S is doing is converting 9 v to 3.3 v in an efficient manner. You theoretically could completely bypass the p/s by providing 3.3 V as long as your external supply can source enough current."
http://imageshack.us/photo/my-images/23/tim001r.jpg/

[sequentialsoftshock]

man-009: Can't reply to you because you have disabled private messages...

[gearfixer]

part is: s-8520f33mc
description: DC/DC Switching Regulators 3.3V Step-Down PWM

unfortunately digikey and mouser is non-stocked. might take some more digging.

I tried to repair a MicroKorg 2-3 years back and I too could not fine the part till I googled it. I found a Sony service manual for a hand held recorder with the s-8520f33mc part on its part list. I went to a local electronics shop that I work from now and got the part for way to much money and I still could not get it to work. I also changed 2-3 other parts and still could not repair it.

http://www.ebay.in/itm/S-8520F33MC-SMD- ... 0228730458

[man-009]

synth was sent out to matt who knows his stuff! will let you know how it pans out with the repair!

[gearfixer]

synth was sent out to matt who knows his stuff! will let you know how it pans out with the repair!

I Would like to know!
The person who owned it would like to get all the setting out of it. The thing was done form the being on the road but and was part of there bands sound.

[man-009]

i'm sure the custom patches are now gone. my guess is the synth will have to be reset for factory sounds. we will see.? will let you know. the synth still may be damaged further depending how far the spike traveled.

[man-009]

i see a few more dead microkorgs on ebay now with the same prob.