@@joomzb:⁠-⁠) Great!

@@c.meyers2882 Thank you!!! No I haven't relubricated the keys, just cleaned them. I don't think they were lubricated from factory. If I would lubricate I'd probably use lithium grease, but in very small amounts. I'm out travelling so I can't check the schematics. But you could check the resistors by de-soldering one end and hope you're lucky. But it's more likely that the display is dim by age. Good luck and enjoy your M1.

Thank You! Yes, synths can have a sentimental value. In my case it's the Korg Monopoly I've had since I was a kid and I'll never part from it. I'd recommend practicing soldering a lot first on other cheaper stuff and building things like guitar pedals or cheap electronic kits and also desolder components from old scrap circuit boards before doing synths.

They are usually marked differently with N.P. and no stripe on the minus side.

The sysex process is not very intuitive. Try to find some M1 sysex tutorials. To check the memory, you could record something simple to the sequencer. If it's still there after a reboot the memory works.

No, and I haven't heard of anyone who has it either. 😐

I haven't had this problem and I don't really understand what it sounds like. But for troubleshooting I'd check the different outputs separately to see if it's related to any specific output. Headphone, 1/L, 2/R, 3, 4. I'd also check if it's present with the effects turned off

@@tukler2 In fact, if you remove it it lasts a few minutes and it comes back normal. Wouldn't it have anything to do with the power board? from some condenser

Yes. It could be a condenser there, or somewhere else. To be sure you'll need an oscilloscope and probe around. Or do a shotgun repair and replace them all. The power supply is the one that could cause most damage if it's faulty.

@@tukler2 In fact, the transitor of the 3-pin power board I see that it gets hot enough. Is that normal? And what is the shotgun and the oscilloscope

I can't say how hot the transistor will be under normal conditions. But they shouldn't be too hot to touch if they don't have a heatsink. An oscilloscope is a device that visually displays and measures waveforms of voltages and audio. You can then probe around on the boards check for anomalies. The shotgun method is to not bother finding the specific faulty component, but to change them all in hope of also replacing the one causing the problem.

No, not really. It should be related to the overall scaling of the synth. Have you done the pitch and scaling calibration like in this video? And have you checked the voltages like in my other video?

@@tukler2 yes, done all the voltages, vco offset etc

@@victoriajakeman This is from the original Arp Odyssey's Service manual page 7 (dl.lojinx.com/analoghell/ArpOdyssey-ServiceManual.pdf). I haven't found any Behringer Schematics, but hopefully it's similar to the original. 2.1.4. TRANSPOSE SWITCH Half of the transpose switch is connected to the bottom end of the resistor chain to, in effect, add two or four octaves worth of resistance (about 1200 or 2400 ohms) to the resistor chain. This raises the control voltage level supplied to the CV memory. The following chart summarizes the CV output for low 'C' and high 'C' on the keyboard for each of the transpose switch positions: TRANSPOSE SWITCH: DOWN 2 OCT. NORMAL UP 2 OCT. LOW 'C' OV +2 V +4 V HIGH 'C' +3 V +5 V +7 V The remaining half of the transpose switch compensates the second voice control voltage for the difference in the resistor chain resistance.

I'd love to get the Behringer one too, I've only got a copy of the original Arp service manual.

@@tukler2exactly, same here. I went as far as to ask behringer and community groups of behringer but they have no idea as well. I have never ever come across a unit without a complete service manual. No idea what logic part no. chips they have installed, mainly they used surface mount components which don’t even have markings, it oblivious to tech service and I don’t know where to start from. The pcb and the design is shocking, the only solid thing on this unit is the keyboard and case everything inside is cost reduced and uses aroun more then 10’different part manufacturers.

They should be replaced if they bulge or leak. The power supply board is most critical and a failure there could cause other components in the synth to fail or burn out. On the other boards symptoms to look out for is increasing noise, or other weird behavior. They could be fine for 60 years. But keep an eye on the power supply.

@@tukler2 By the way, where can I buy the original microswitches for the M1?

You can buy them from Syntaur, Mouser, Elfa and many other places. syntaur.com/Part-3381X-Pushbutton-tact-switches-pkg-of-10

Yes, it's done at the factory. And there's no need to do it until the synth doesn't play in pitch. It could take years.

@@tukler2 they forgot to put the plug back it…. and it’s hard to find a replacement part so small.

@@petert8507 Keep on looking, I hope you'll find one. I don't think it’s critical though.

@@tukler2 I’m just a bit OCD when it comes to things like this.

I've not seen this problem before. If all the white LEDs all faded and gone dead my wild guess would be that they been driven too hard. Is the voltage OK? And how high is the current? Is there a resistor that limits the current? By just replacing the LEDs might cause the new ones to die quickly. But that's my wild guess and where I'd start troubleshooting.

@@tukler2 Voltage Seems Good at 9.1V input, the symth CV calibration is at steady -5,0,+5,+8V. For now seven of the white multi-color ones are out, Im looking for loose connections or faulty components, when it was dyiing out it was slowly flickering on and off and going dimmer then the others. Im still testing voltage vantage points to see if any of these are higher then the others. The Behringer PCB is not of good quality, very flimsy witha ,Lot of Factory Flux residue and finger marks. I tooked the whole thing apart for further inspections, somehow th 7 LED's are tied to each other. Im Giving it a break now and will have to continue tommorow.

They should be the same, though Korg have different part numbers in the service manuals. Syntaur sell the same switches to both synths

I haven't looked in to it, so I don't really know. I don't have any schematics, there might be just an mono DAC. But it would be nice to have the effects in stereo.

Thank you and good luck with the repair!

A small Phillips screwdriver will work and even a small flat head one will do the job. How much do they differ? It could be a component that’s out of spec. Or it could be just slightly off, but still in spec. Does it still calibrate OK? In a perfect world they would be perfectly matched, but this is analogue technology so they can be slightly off an still calibrate OK.

@@tukler2 thanks for your reply, just came back to this. At the alternate test points I get +14.96v and -14.70v . Unfortunately I can't get down to 1mV level with my multimeter, but by comparison I have +15.01v and -15.00v at TP2 and TP3 respectively. The tuning seems to have calibrated fairly well, though I needed to adjust the offset for both oscillators first. There is some noticeable, almost stepped pitch drift from oscillator 1 when it's left to drone, though it seems to snap back in tune each time. I got a static shock calibrating the rails the first time which is what made me think I may have shorted a component.

@@electric_fields I'd leave the way it is if it's playable. -14.70 is a little bit off. It's a bit of work to troubleshoot. But you could try trace the culprit by disconnecting things and check if some components are too hot.

Maybe soon you'll have a 4th one too ;-)

@@tukler2 myślałem o czwartym. ;););)

Thank you! I'd definitely check the voltages, even a cheep multimeter would do the job. Pitch calibration and scaling can be tricky and it's hard to get it perfect, it helps if you're stubborn and don't give up. But if the voltages are out of spec the scaling will never be perfekt. Keep in mind that this is old analog technology and it will probably never be 100%. Good luck!

@@tukler2 I'd already picked up a multimeter in preparation and with a lot of hours and plenty of perseverance (stubbornness) I believe I've solved the issue. Using a mix of your techniques and some trial and error with the VCO1 offset + the lower octave scaling. It's videos like yours and the knowledge you share that make KZbin and the internet in general a glorious place. Thanks for your response too! Take care

Is it's a fresh battery and orientated the right way with the positive side up? I don't think I can help you. But I'd start troubleshooting with a battery that measure fine and is fresh. Does the synth drain the battery or is it OK with the synt reporting the battery low message. does the synth keep the memory when powered off? The display could be dim because of old age but otherwise that could be an indication of a fault. I'd check all the connectors, the voltages and the grounding points are grounded. Look for things that look broken or burnt and check for leaky or bulging caps.

Yes, is the short answer.

If you mean the joystick potentiometer, i can't recall which one I bought, but I had to mod it to fit. You can buy the correct one here: syntaur.com/Part-3766-Potentiometer-10KB-rotary-with-center-tap

First, make sure the mains cable is unplugged. The caps should drain after a few minutes, but to be safe you could run a screwdriver over the back of the board to discharge the caps, by connecting their pins together with the screwdriver. I can’t really tell the best temperature since the dial temp on different soldering stations varies and doesn’t reflect the reality. But it should not be too hot, but just hot enough to easy melt the solder at the pins in a couple of seconds. Try to be as quick with soldering iron as possible. It might help to put some new solder on the pins before desoldering. I’d recommend that you get some old radios or other electronic equipment from the 70’s and 80’s to practice on some scrap circuit boards first. Good luck and happy soldering!!!

@@tukler2 Thank you for the reply. My iron is a Weller brand, so I think it is fairly consistent with its digital temperature dial in degrees F. Can you tell me a few common mistakes to watch out for while attempting this recapping? Will too much heat melt the traces in the pcb or destroy the cap? Should I tin the pins of the new capacitors first? The caps with a specific polarity are usually labelled? Thanks!

@@anonymous_friend Too much heat will lift the traces from the pcb. There are other more heat sensitive components on the board, and the caps should be fine unless you go really hot or heat them up for a long time. The adding of extra new and fresh solder is to make the desoldering easier. You shouldn't pre tin the new caps. A common mistake is to reverse the polarity of the new electrolytic caps, or to replace with the wrong cap. Be systematic and don't hurry. Traditional lead-based solder is easier to use and have a lower melting point than the newer lead-free solder. A really good solder sucker and high quality solder wicks makes life much easier.

Any digital oscilloscope with two channels would probably work. I'd prefer a bench top scope. There's also a lot of second hand ones out there that could be a bargain compared to buying a new one.

Yes it could be in the D/A board or some filter after the D/A, but before the outputs. Could be a bad capacitor somewhere. Check to see if it also on output 3/4. An oscilloscope could be useful to trace the noise. Good luck! /Anders

Thank You very much!

I'm happy to to hear that! Thank you for your feedback. :-)

Below is my list with the Mouser number, you can use it as a start. They might have replaced some with new ones, but you can use it as a start. Replace electrolytic capacitors with the same capacitance and with the same or higher voltage values. Make sure you notice which capacitors that are bipolar. There are a couple of capacitors that I had to bend slightly to fit. I think it was the 470 uF. I used 35 volts ones with a hight of 20mm. I'd probably go for a 15 mm or 16 mm instead. But I general new capacitors with the same specs are usually smaller today than they were in the 80's. I'd take all the boards out and identify all the caps and values before I make my order. 667-ECA-2CHG010 Aluminium Electrolytic Capacitors - Leaded 1.0UF 160V ELECT NHG RADIAL 667-EEU-EB1H100S Aluminium Electrolytic Capacitors - Leaded 10uF 50V 667-ECA-2GHG470 Aluminium Electrolytic Capacitors - Radial Leaded Al Lytic Cap Radial NHG Series 105C 667-EEU-EB1H101S Aluminium Electrolytic Capacitors - Leaded 100uF 50V 667-EEU-FC1H221S Aluminium Electrolytic Capacitors - Leaded 220uF 50V 667-ECA-1EHG221 Aluminium Electrolytic Capacitors - Radial Leaded 220uF 25V 667-EEU-FM1V471 Aluminium Electrolytic Capacitors - Leaded 470UF 35V ELECT FM RADIAL 667-ECA-1AHG222 Aluminium Electrolytic Capacitors - Radial Leaded 2200uF 10V Bipolar: 647-UEP1H010MDD Aluminium Electrolytic Capacitors - Leaded 50volts 1uF 0.2L/S 647-UEP1C100MDD Aluminium Electrolytic Capacitors - Leaded 16volts 10uF 20% 647-UEP1C220MDD Aluminium Electrolytic Capacitors - Leaded 16volts 22uF 20% God Luck!

@@tukler2 Thank you very much for the detailed answer. I really appreciate 🙏🏼

Are the loud keys always the same keys? I'd probably clean and check the keyboard assambly and its connectors first (reseat all the contacts from the keyboard) . The "rubber" key contacts should be clean and so should the gold contacts that they press against. Weird problems could also be a result of a bad ground connection

@@tukler2 no sometimes i play the same key twice and one time it acts strange like noise or sustain and other time it plays well.

Does it play well over midi? If it does it should be a keyboard problem.

@@tukler2 i have to try it cheers mate

If you're in France you can buy them from www.mouser.fr www.distrelec.fr fr.farnell.com

Thank You!!!

Thanks! :-)

Check that all the voltages from the power board are ok and within spec first. Look for loose or unplugged connectors and reseat them all. Try to go fore the simple things first.

There is no need to do it unless the pitch, tuning and scaling starts to bother you.

@@tukler2 thanks

Wouldn’t this be done in the factory?

Yes, it's done at the factory. But mechanical, environmental factors and time could make the calibration to drift to the point that it's necessary to do a new calibration.

Looks like you have some trouble shooting ahead of you. First I'd check that if the distortion is the same on all outputs. Then I'd trace the audio signal back on the PCB's with a oscilloscope or an audio probe (something like a small battery powered audio amp with one lead connected to audio ground and probing through a capacitor to prevent DC from getting into the amp). Just try to find where the distortion is introduced, If it's in the analog part of the circuit. Make sure you stay safely away from the mains part and don't cause any short circuits and only follow the audio route.

Have you already tested it on 110 volt? It shouldn't work if it's made for 220 volt, unless it's modified. Check the labeling on the back. The only way to use an European (220v) Korg M1 in US/Canada is to plug it in to a step down transformer, or to change the power supply board. The European uses a KLM-1269, and the US/Can KLM-1269

@@tukler2 Yes , works fine ,the label says 22ov. Just wondering if I'll burn anything out.

@@dusanljubec7203 Don't run it on 110v if it's a 220v device. It'll be damaged. Be sure that it's a 220v power board inside (unscrew the bottom plate and check that the Power board is the European 220 volt KLM-1269). Then buy a step up converter www.amazon.ca/110-220-Voltage-Converter/s?k=110+to+220+Voltage+Converter They aren't that expensive.

@@tukler2 Thanks a bunch !!!That is what I was worried about . I'm defiantly taking your advice.

Thank You!

I have not found any, I don't have the Korg or the service manual. But there should be a simular process of calibrating the power supply. There's a good teardown video here: kzbin.info/www/bejne/aqGXf4ifgNyrptE

@@tukler2 Thank you for this video and the link!

I've soldered two wires with alligator clips to an ordinary tele-plug the line out jack. An easier way (if you don't allready have one made) would to use just a bare plug and connect the probes directly to the plugs connections.