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broken korg emx-1 with high pitched buzz on outputs
Posted: Wed Apr 27, 2011 8:54 pm
by intellijel
I bought an semi-broken Korg EMX-1 as gamble that it might be easy to fix. The problem was described as a low buzz on the main outs but it has become a pretty loud high pitched digital sounding noise on all outputs.
What would be your best guess of something that could spontaneously break/degrade to produce this issue? My first instinct is power supply filtering issues but I don't know how that would have just suddenly occurred on what is relatively new equipment (compared to a vintage synth for example)
Posted: Thu Apr 28, 2011 4:06 pm
by pSyDeViAnT
crap dead or dying valves ,,, maybe ,not sure
Posted: Thu Apr 28, 2011 5:07 pm
by hazabikit
Sounds to me like someone dropped it (maybe repeatedly), and there's one or more loose or bad connections inside.
Posted: Sat Apr 30, 2011 5:57 pm
by intellijel
pSyDeViAnT wrote:crap dead or dying valves ,,, maybe ,not sure
Pretty sure it is not the tubes since outputs 3+4 bypass them and they still have the noise issue. (I even tried unplugging the tubes).
Posted: Sat Apr 30, 2011 5:58 pm
by intellijel
hazabikit wrote:Sounds to me like someone dropped it (maybe repeatedly), and there's one or more loose or bad connections inside.
It was definitely dropped (got damaged in shipping) but I opened it up and tried re-seating the connectors and no change so far.
Posted: Sat Apr 30, 2011 7:31 pm
by xmlguy
When you trace the signal on an oscilloscope, what do you see?
If you don't know how to do that, then you shouldn't be messin' with it. You really do need to know how electronics work in order to fix most problems.
Posted: Sat Apr 30, 2011 10:10 pm
by intellijel
xmlguy wrote:When you trace the signal on an oscilloscope, what do you see?
If you don't know how to do that, then you shouldn't be messin' with it. You really do need to know how electronics work in order to fix most problems.
I am an electronic engineer so that is not a problem. I can start trying to trace but it is dense circuitry and obviously no schematic. I will do this eventually but I wanted to save time first and see if it was a known symptom for a common problem.
Posted: Sun May 01, 2011 5:59 am
by xmlguy
intellijel wrote:xmlguy wrote:When you trace the signal on an oscilloscope, what do you see?
If you don't know how to do that, then you shouldn't be messin' with it. You really do need to know how electronics work in order to fix most problems.
I am an electronic engineer so that is not a problem. I can start trying to trace but it is dense circuitry and obviously no schematic. I will do this eventually but I wanted to save time first and see if it was a known symptom for a common problem.
Schematics are in the service manual, and if you search this forum, you may find them. Being an engineer, you should know that direct examination of the problem will gather facts and evidence to speed diagnosis compared to wild-assed guesses (WAGs). You can eliminate whole blocks of circuitry from being the source of the problem with a single, well-selected, measurement.
If all else fails...
Posted: Wed Feb 06, 2013 6:24 am
by mrsidman
Hey if All else fails and you need to piece out parts I'm willing to offer for a working LCD and board.
I'm looking around for one, patiently online for an ESX i have collecting dust.
It's LCD is busted and I'm on the hunt for a replacement.