Vintage Synth Repair

i bought from them when I restored a t3 Korg which is soldd cheap to a guy with disks who had thieves steal his machine.  I decided teh K2000 was more my kinda machine and tehy were too close to keep both.



Lorne



From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@...m] On Behalf Of jammie
Sent: April-13-14 3:45 PM
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Korg KARMA Button Issue

 





try guitar parts they have stock of some korg synths that korg uk does not



http://www.guitar-parts.com/catalog/korg-group-2-small-buttons-wled-window-cx3-620032000



http://www.guitar-parts.com/catalog/korg-knob-1-button-led-620032100



----- Original Message -----

From: Lorne Hammond <mailto:lhammond@...>

To: vintagesynthrepair@yahoogroups.com

Sent: Saturday, April 12, 2014 3:17 PM

Subject: RE: [vintagesynthrepair] Korg KARMA Button Issue





and I found on things like the T3 and an M1 I rebuilt that the button tops are often cast as a set in a frame and when one goes it is often a loss of flex or a physical snap of off the supporting frame, so you will be looking for an entire area of button tops.  The tactile switches (good quality of course) are the easy parts.  The second thing is that from the M1 on at least Korgs (and many other brands) are loaded from the back.  That is to say you need to remove every board and cable and shielding wrap in a careful sequence to get to the top buttons.  Old analogs were far easier to work on in terms of getting at the switches.  I always go slowly and use a camera to memorize that disassembly sequence.  First buy or borrow a service manual.  They may sell you one and ask a tech if they can find the part number for the buttons.  They may have a list of suppliers for the old parts and or a cross-reference to the best substitute switch.

I always start with a polite email to the company with teh serial number of my unit.

Lorne

From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Roger J
Sent: April-11-14 10:56 AM
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Korg KARMA Button Issue



Below each button is a tactile switch or tac switch. Often because they are going bad, they require greater pressure to make contact and this damage the plastic button,  Korg today does not stock as many parts and often on older models, the buttons are not available.  Soldering a new one onto the circuit board is easy, harder is removing the defective switch without damaging the circuit board.

Tac switch failure is common.  If you buy replacement switches, make sure to use the higher quality Alps and Panasonic over the Chinese ones.

I typically replace all tac switches if a couple are bad as quite often other will fail next week if I do not do all today.  Getting the button boards out and re-assembling the keyboard require much time,   Having to redo because another failed is costly.  The switches are cheap, labor is expensive.

Make sure each replaced switch is all the way down on the circuit board, as if not, the force of pressing down during use will break the circuit traces and you will have to redo you previous work, plus repair the damage circuit board!.

On Friday, April 11, 2014 2:50 AM, Samuel Adams <SamuelAdams7@...> wrote:





Hi,

While not a real vintage synth, I recently got a used Korg KARMA and noticed that one of the "Chord Trigger Buttons" does not work and another one works sometimes, sometimes not.  I was wondering how difficult it would be for a novice to replace these buttons and where can I get a set?  I can solder fairly well and can usually take apart and put things back together but have no experience torubleshooting.  I'm thinking that the buttons just need replaceing due to wear.

Any thoughts or suggestions?

Thanks

Greg