Suzuki Omnichord om-200m repair

Hello community,
I recently found this strange music instrument without power adaptor & incorrectly powered it.

I’ve since gone to Lee’s to p/u a multimeter capacitors, solder, iron etc… i have enthusiasm to repair it but limited knowledge & would love a more seasoned electronics/ music cat to show me around this circuit board (like new inside) -

I just don’t wish to cause more issues - having replaced 1 cap to no avail (on battery). I also bought the correct adaptor w/no power love.

Anyhoo, let me know if a particular time is best to show up to learn some skills. Will happily donate time & energy to any other people/ projects that require added community support.

Merci,
Benjamin (ps; new to forums/ netiquette - apologies for any erroneous behaviour).

2 Likes

Hi Benjamin.

It helps to post pictures of what you have as well as provide web links to Make and Model of whatever you are trying to fix. Folks will often chime in with things for you to try here or get a better idea of what you need.

Ok will try to add an image to the post retroactively. Thank-you so much for the guidance!

Looks like the power section is the lower right corner of the following schematic.

This would be the first area I would investigate.

http://www.suzukimusic.co.uk/omnichord-heaven/service/OM-100.pdf

This schematic for the OM-84 is more readable. It’s a different model but the PS portion of the circuit looks fairly similar to the OM200 so you might get a better sense of what the individual components are.

Also can you describe what you did to “incorrectly” power it?

1 Like

check the voltage regulator 7805. and diodes in the incomming power circuitry. There seems to be a few zener diode to clamp voltage to below 10v but if you used a modern psu. You might of shorted some components.

Those older instruments use a centre negative power supply. See if it works on battery.

meow

1 Like

@existentialdetective I hope you also have the proper headband to go with this fantastic instrument. :smiley: I can’t help but I am looking forward to seeing what you get up to with this.

@existentialdetective Check out this YouTube video.

The repair is likely what you want.

Suzuki Omnichord OM100 Repair - Won’t Turn On, No Power

2 Likes

Hello thanks for all of this info. I will investigate over the weekend. To explain the issue - unit was running on battery power when i got it a few weeks ago, sounding warbled but working.
(I assumed the batteries were low on power)
I took out the batts & (here is my error)
I used a common 12v wall adaptor that i thought was correct - however, it had the opposite tip to what was needed (neg/ pos) - there is a symbol on the unit showing it needs negative polarity. After trying this out to no avail, i then inserted new batteries & noticed the battery power no longer worked. When i opened the unit i saw a capacitor that i thought was bulging. So i replaced that (faced the cap in same direction as the potentially burst one) & got the correct power adaptor.

The unit is not turning on with battery or adaptor

2 Likes

yes, thanks, this is the vid i found after i used the wrong adaptor. very illuminating. i will need to keep testing to find out what else on the board may be faulty. I am brand new to the multimeter so i have a learning curve ahead.

1 Like

hehs, it actually came with an 80’s tennis racket styled shoulder bag & a christian book of omnichord songs, so the headband pic may just be a photoshop halo if i can get this unit playing ;p

1 Like

ok, my heartfelt thanks for this, feline… =new electronic vocabulary to look up & learn from.

& it did work on battery before i incorrectly powered it/ now it won’t work (even with new batts or proper adaptor) so i def think your input is going to be valuable in omni-resurrection,

2 Likes

I just want to jump in here because the little <3 on a post isn’t enough. This repair is super exciting. Please keep us in the loop.

If you are a member, (or if you aren’t and become a member) please join us on #musicnerds on slack. There’s a bunch of us who love this sort of stuff, and we are even making a community-sourced eurorack for making all sorts of strange sounds.

1 Like

Google metro van repair cafe or something. I’m to lazy to do find the link. Sorry.

You can probably bring it there and meow at someone untill they help you. I think they do it monthly in Vancouver somewhere right meow. You have to register though. They have one tomorrow… But I think deadline for it is already passed

I’m pretty sure they can explain how to troubleshoot your unit and explain a few things about electronics

Meoww

Next event is July 16. register go there and meow at the freegeek booth. They will stare at you weirdly or maybe help you.

(Bribing the cat with food also helps)

ah drats katze,

i’ve got a nature getaway -that- weekend. The repair event you mentioned looks like an unparalleled opportunity for community learning (link below).
i’ll bring the omni, chat & chews on aug 13 or sept 10 (meanwhile i’ll purr on back to Lee’s to get a few more components :smile_cat:)

https://www.vanrepaircollective.com/

thank-you for your enthusiastic message mike, this all sounds amazing (sorry for the weeklong delay) i don’t know what a slack is but will def investigate further. also, the community eurorack is a brilliant idea… forget the bach, it’s
‘switched-on rack’ ;p

1 Like