Korg Forums

[amyfletcher@ymail.com]

hi all..
i have a big problem with my ms2000r. if someone could please help me out..i tried the boards and forums but cant find a solution..and no im not a ditsy girl lol..here goes..

for the last few months, i noticed that it takes loner and longer to switch between the sounds..then some sounds wouldnt play at all..

today,while in the middle of recording a track,my friend pressed something and now nothing works.

it turns on, and i can scroll through the diffrernt sounds+menus, but midi isnt registering and no sound comes out of the 1-16 buttons work if i press the keyboard button on the left (out of the outs or headphone port)..

i tried the firmware upgrade and am now running 1.7 (though it says 7 on the screen) i think..
i did the menu->2d->global/program reset and still nothing..
i did the re init: hold mod key+3..it scrolls through the menus, then freezes on midi and says something like "midi loop error"..no sound comes out of the outs, but a sound like a layered midi time code comes out of the headphone port..

my setup is: m-audio keys->motu microlite->2000r midi in->2000r midi out->microlite..via protools 6.9 on xp quad 4gb ram..

thankyou all so much in advance...

[xmlguy]

Unplug the 2000R midi out cable from the motu microlite.

Then powercycle the 2000R and retest.

If that fixes the problem, then you are probably creating a midi feedback loop, in which the midi output by the 2000R is getting sent back to itself.

To fix the problem permanently, you need to check for any midi "echo" parameters in the driver for the motu box or in the DAW software that your using, so that you can disable the echo. Then you can rehook up the cable and everything will probably work fine.

[amyfletcher@ymail.com]

hi..
thanks but no cigar...i even unplugged both midi cables from both ports..
still freezes on midi screen with loop timeout error..
really dont know what to do...
but thanks for your suggestion..

[xmlguy]

Is the Global Page 3B Local set to ON or OFF?

[amyfletcher@ymail.com]

Thanks for the idea, but local is set to "ON"..

[Alan Waddington]

Maybe the hardware loops midi out to midi in as part of diagnostics and there's a hardware failure that is causing it to get stuck on or off.

You could try intentionally causing a midi-loop by plugging a cable from in to out, powering on. Maybe then remove the cable or set LOCAL to off.

If that has any effect, it would at least point to the area of the problem.

Edit: I found the service manual on the web.
http://www.loscha.com/scans/Korg_MS2000_Service_Manual.pdf

There doesn't seem to be any hardware loopback right at the outputs. The MIDI interface is powered from a 5V regulator (which also drives the mod and pitch wheels - so if there were any problems with those before failure, that might point to the 5V regulator. The 5V does come out of the MIDI port, so if you have a multimeter, that is checkable. Still, I can't see how that would cause the error.

Incidentally, that 5V regulator also seems to power a reference linked to master volume (I think), so is definitely worth checking. It's on pin 4 of MIDI thru and MIDI out connectors.

The MIDI Input/Output comes from a HD6412350 which is a microcontroller. Possibly that has become damaged, although since it does a lot more than just MIDI, I suspect that any damage would be limited to failed output pins.

[amyfletcher@ymail.com]

I decided to experiment and see about the "MIDI loop check error". I connected the MIDI in and out together. I ran the on+modkey+3..
The test started up..
1.Dsp Dram Check (passed I guess),
2.Midi Loop Check - Started with noise then passed I guess
3.Then for a very short time, a blank screen came up.
4.SW & LED test all led on. All the lLEDs lit up because I pressed the cursor button and the next menu was,
5.Sys Rom check
6.SW&LED test Audio In1 (I patched cd out (patchbay) into Audio In1 and sound came through left channel after turning Audio1 pot up-headphone out), then I pressed the cursor button and the next menu was
7.Same for Audio In2..Right channel though. I pressed the cursor button and the next menu was
8.Then the Osc1, Osc2 etc..

I think this testing is a program based "self check" diagnosis to see where a problem might be.

Now I am stuck at SW&LED test..21 arp ran (tempo pot). I turned the pot left to right fully, and the red light stays on.

Any ideas? At least this might be some kind of indicator.

[amyfletcher@ymail.com]

Also I recorded the sound during the MIDI loop test. Caution: It's a high pitched and loud..(https://rapidshare.com/files/3058819297/MS2000R_Sound.mp3)

[Alan Waddington]

Not sure if you meant the ARP Tempo or AMP Pan knobs. Might be worth checking you got the right one.

Still they are both connected to the same multiplexer chip at grid ref 3G on circuit diagram sheet KOD A30415 (See earlier link to service manual).

Thus if you can't get past that test, the problem may be around that block of potentiometers or IC4.

Edit: I listened to your sound file. Maybe noise is cross-coupling across through the power supply, which could be at fault. I don't think I've got much chance of guessing more accurately.

[amyfletcher@ymail.com]

The pot is the ARP tempo (between amp pan/direct level and gate pot)..

I'm really bad with the electronics part of audio. Last tme I touched a soldering iron or voltmeter was in Uni about 15years ago lol..

I was thinking about the cross coupling. I have the 2000r going into a step down transformer (240V->120V the unit is US power), then transformer to 240V AC. I though the transformer would "transform" the 3 phase 240V AC we have Australia to the 1 phase 120v AC. Maybe I'm wrong.

This is turning into a nightmare.

[Alan Waddington]

I think you have 3 phase star in Australia. The voltage between each phase and neutral is 230V AC. So putting one of those phases through a 240V to 120 step down transformer should get you the right voltage. (Don't wire directly across two phases through as there's about 400V there).

Actually, I was thinking about the power supply components inside the MS2000. These take the voltage from the MS2000 PSU and convert it to 3.3V for the DSP chip and microcontroller; 7V for the Audio circuits and 5V for the MIDI and potentiometer (the knobs) circuits. There are lots of capacitors across the various power rails which smooth the voltage and reduce the noise.

Capacitors (electrolytic ones) get old and often fail after about 10 years, so one possibility for the midi signal cross coupling into the audio, is that the midi driver is causing switching noise on the 5V rail (which should be removed by the capacitors). However if it is not, the 5V regulator will couple the noise back into the 7V power rail from which it sources its power. Since the 7V power rail provides power for the audio drive circuitry, the midi noise will get coupled into the audio outputs.

However there may be some cross-coupling between midi and audio in normal operation. It may only be audible when there is no sound being generated and the external audio gain is turned right up. If you can hear the midi noise with normal volume settings, this suggests there is a cross-coupling problem.

Since the 5V power rail is used as the reference voltage for the potentiometers (knobs), any problems with the 5V will show up as problems in controlling the knobs. If the 5V rail fails altogether, then all knob control will be lost and midi will be lost. If however problems are only related to a few knobs, then this may indicate that the multiplexer (e..g. IC4) which routes the knob voltages for measurement is faulty. If the problem is a single knob, then the knob potentiometer is faulty. This could be that the wiper contact has failed (quite likely), so there is no voltage picked up from the knob, or alternatively the 5V reference voltage wired to that knob could have become disconnected (less likely as it's probably a direct pcb connection).

The reason for going on about the knobs, is that if one of the Level knobs fails, it is possible that the MS2000 thinks you have turned the audio level down to zero and that's why there is no audio output. If the connection had become intermittent, it could be that when you changed patch, some flexing of the circuit board occurred causing the potentiometer to stop reading and the audio to drop out. Potentiometer failure is a common fault. However the same could happen if the 5V rail had an intermittent fault.

Overall, I think you probably have an electronics failure somewhere. The trick is to try to localise the fault to a specific function and then look at the circuit and think of possible causes. Unfortunately at this point you will need to open up the MS2000 and measure voltages with a multimeter. Obvious things to check are the 5V and 7V power rails. If you put the meter onto DC it will show the average DC voltage. If you put it onto AC and put it on a sensitive range, you will be able to see the noise on each power rail (which should only be a few millivolts). Lots of noise would suggest a failed smoothing capacitor.

You could also check the audio signal path by monitoring at various points (you may want to put the meter onto AC voltage for that). You could also check the voltages at the potentiometers (probably probe points on the back of the pcb).

You might need to get some help from an electronics techy for the above. Alternative the MS2000 needs to go back to Korg Service, but since they would replace the entire circuit board, it is unlikely to be cheap.

The problem with all the above guessing, is that it is just that - guessing. The fault may well be something else. I can only explain the kind of things I would look for and how to eliminate them from the list of possibilities.

[Alan Waddington]

There's also a possibility of a faulty DSP chip, as these seem to fail. Although you would probably see a DSP related error code in that case and I see your MS2000 passed the DSP DRAM check.

http://www.korgforums.com/forum/phpBB2/viewtopic.php?p=456169&sid=55c3a078248293d00b776ca09ec8486b

[amyfletcher@ymail.com]

Hi Alan,
I read that thread before (thanks ). From that post, the dsp test failed. Lucky in my case, the trouble is during the pot diagnostics.
I wish it didn't cost so much, but it looks like I have to send it interstate for a korg tech rep to "look at it".. There's no way I can do that level of electronics..oh well..I guess I should have paid more attention @ uni lol..

[SeedyLee]

Hi,

The symptoms you're experiencing seem to be common with a few others that have experienced DSP failure. It's not an expensive part, but soldering it in is time consuming and delicate.

What state are you in, and where have you been advised to send it?

Also, rather than using the 240V to 120V step-down transformer, keep in mind that it might be better to simply replace the power-pack with an Australian version for around $15.00.
_________________
Korg Kronos 61, Triton LE 61/Sampling/64MB/4GB SCSI (Sold, sob), MS2000BR, Monotribe, Monotron, NanoKontrol, NanoKeys, Kaossilator II, Roland JV-80, Kawai L1, Casio HT-3000 (Sold, sob), Lexicon MX200, Motu 828 mk3, Presonus FaderPort, Motu MicroLite, Rode NT1-A, Tascam VLX5 Monitors Tascam CD Player, Shure SRH840 Headphones. Shure IEM, Shure SM58, JBL PRX12 monitor wedge.

[amyfletcher@ymail.com]

Seedy: I dont' think it's a DSP error. During the tests, the 2000r passed the DSP DRAM check. I wish it was the DSP, because the part is cheaper to replace then the whole board (if that's the fault). It seems that I'm the first with this type of problem. Not only have the guys looked at the problem on this forum, but I've tried other boards and forums, and no one has come across this problem before. Even when I contacted Korg US (via email), they didn't have any relevant tips
I'm in NSW and MusicLink in Melbourne is the only authorised Korg repairer in Australia I called them, and got the obligatory: "Well you'll have to send it in, and you'll have to pay for us just to open it up". Even if they open it up, and can't find the problem, it's 2x postage and a service bill, just to open the unit up. Even though I explained in detail (like this forum) the step by step actions/errors, they still couldn't tell me what the problem is (and they are the experts?). I've had way better help from this forum..
It's pretty sad that in such a vast country like Australia, there's only ONE Korg repair centre for the WHOLE country Well that's my mini rant lol..

All: I've decided to take the whole studio apart. Since I was down about my 2000r, I decided to treat myself (a very rare occurance) and get myself a; Novation A Station and a Korg Tr Rack yay. I'll have put them in the rack anyway, so thought to redo the whole setup.
While the studio is down, I'll give the ms2000r to my Uni friend who is pretty handy with electronics. I'll copy the posts so he can get an approximate idea of whats happening. I'm crossing my fingers that this can be fixed..
Thanks for all the though you guys put in .
Please feel free to add any more ideas/options...