dead microkorg

Pulling out your hair? Don't know what to do or where to go? Ask in here.
Forum rules
READ: VSE Board-Wide Rules and Guidelines

If your Help request has been solved, please edit your first post in order to select the Image Topic Icon to let others know your topic has been solved.

Re: dead microkorg

Postby man-009 » Fri Feb 17, 2012 7:41 am

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.
man-009
Supporting Member!
Supporting Member!
 
Posts: 398
Joined: Sat Jun 20, 2009 11:54 pm
Band: Man-009

Re: dead microkorg

Postby Steve Jones » Fri Feb 17, 2012 1:07 pm

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.
Synthesizer service tech since 1982.
Synth parts and service, Sydney Australia.
Steve Jones
Active Member
Active Member
 
Posts: 565
Joined: Wed Apr 23, 2008 10:40 pm
Location: Sydney
Real name: Steve

Re: dead microkorg

Postby man-009 » Fri Feb 17, 2012 5:16 pm

that sucks. so what is it worth for parts? it is in mint condition? may need to sell it.
man-009
Supporting Member!
Supporting Member!
 
Posts: 398
Joined: Sat Jun 20, 2009 11:54 pm
Band: Man-009

Re: dead microkorg

Postby garranimal » Sat Feb 18, 2012 12:58 am

Steve Jones wrote: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. :(
User avatar
garranimal
Synth Explorer
Synth Explorer
 
Posts: 1728
Joined: Mon Sep 27, 2004 8:57 pm
Location: USA

Re: dead microkorg

Postby man-009 » Sat Feb 18, 2012 4:10 am

man..i hope batteries work? prob dead though..:(..testing monday! wish me luck~
man-009
Supporting Member!
Supporting Member!
 
Posts: 398
Joined: Sat Jun 20, 2009 11:54 pm
Band: Man-009

Re: dead microkorg

Postby man-009 » Mon Feb 20, 2012 11:01 pm

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/
man-009
Supporting Member!
Supporting Member!
 
Posts: 398
Joined: Sat Jun 20, 2009 11:54 pm
Band: Man-009

Re: dead microkorg

Postby adhmzaiusz » Tue Feb 21, 2012 2:19 am

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
Active Member
Active Member
 
Posts: 269
Joined: Tue Jan 29, 2008 8:27 am

Re: dead microkorg

Postby adhmzaiusz » Tue Feb 21, 2012 2:25 am

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.
‹‡›
adhmzaiusz
Active Member
Active Member
 
Posts: 269
Joined: Tue Jan 29, 2008 8:27 am

Re: dead microkorg

Postby man-009 » Tue Feb 21, 2012 3:19 am

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/
Last edited by man-009 on Wed Feb 22, 2012 11:19 pm, edited 1 time in total.
man-009
Supporting Member!
Supporting Member!
 
Posts: 398
Joined: Sat Jun 20, 2009 11:54 pm
Band: Man-009

Re: dead microkorg

Postby sequentialsoftshock » Tue Feb 21, 2012 6:32 pm

man-009: Can't reply to you because you have disabled private messages...
bonne chance
User avatar
sequentialsoftshock
Synth Explorer
Synth Explorer
 
Posts: 2413
Joined: Thu Jan 28, 2010 1:57 am
Location: Paris / Philadelphia
Real name: Zayne
Gear: Pro~One, MS20, MPC60, Aalto, Volca Beats, Volca Keys, Beatstep, Casio MT18, BitOne (sorta), Circle, Orbit 3, K5, Stylos, Univox Hi Flier, iPad
Band: Echo & Liora

Re: dead microkorg

Postby gearfixer » Tue Feb 21, 2012 8:06 pm

adhmzaiusz wrote: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
Image
User avatar
gearfixer
Junior Member
Junior Member
 
Posts: 154
Joined: Fri Feb 12, 2010 8:02 pm
Location: New Brunswick
Gear: ARP Pro DGX, Avatar, EX 800, RS101, VK-8M, Juno 60, 200a, Fast 5, and Rhodes MK1 stage 73.

Re: dead microkorg

Postby man-009 » Wed Feb 22, 2012 9:13 pm

synth was sent out to matt who knows his stuff! will let you know how it pans out with the repair!
man-009
Supporting Member!
Supporting Member!
 
Posts: 398
Joined: Sat Jun 20, 2009 11:54 pm
Band: Man-009

Re: dead microkorg

Postby gearfixer » Fri Feb 24, 2012 1:20 am

man-009 wrote: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.
Image
User avatar
gearfixer
Junior Member
Junior Member
 
Posts: 154
Joined: Fri Feb 12, 2010 8:02 pm
Location: New Brunswick
Gear: ARP Pro DGX, Avatar, EX 800, RS101, VK-8M, Juno 60, 200a, Fast 5, and Rhodes MK1 stage 73.

Re: dead microkorg

Postby man-009 » Fri Feb 24, 2012 1:46 am

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
Supporting Member!
Supporting Member!
 
Posts: 398
Joined: Sat Jun 20, 2009 11:54 pm
Band: Man-009

Re: dead microkorg

Postby man-009 » Fri Feb 24, 2012 5:55 pm

i see a few more dead microkorgs on ebay now with the same prob.
man-009
Supporting Member!
Supporting Member!
 
Posts: 398
Joined: Sat Jun 20, 2009 11:54 pm
Band: Man-009

PreviousNext

Return to HELP!

Who is online

Users browsing this forum: Bing [Bot], Pushpull76 and 16 guests