[Korg] [Prologue] – [no-power after firmware update]
Hi, I am new here, so I hope I am asking correctly.
I tried updating my Korg Prologue 16 to latest firmware, but it stopped with a message that it was not able to finish. I tried sending it again to the synth, but the synth did not respond. Then I did the stupid thing and turned it off in hope that I could start over again.
Now it does not turn on at all. No lights or anything.
I read briefly on another forum that someone was told after doing similar thing that the main board needed to be replaced.
Does anyone here have experience with this?
• Model & revision/OS: 2.1
• Symptoms (what changed, when): Firmware-update failed when updating to os 2.1. Now the synth does not turn on.
• Tests already done (voltages, parts replaced): No parts replaced.
• Photos / audio clips:
Thanks for the suggestion, but I don’t have neither the knowledge or the tools to do this.
I found the mainboard on Synthaur webshop, and from the picture it looks like it is something I can just replace without soldering anything.
I guess my real question is: Does anyone know if replacing the mainboard would fix my problem?
The next question would be: It says in the description of the part that it needs programming or updating. Does it mean that I need to do the same firmware-update I tried to do, or does it need special equipment?
I have contacted Korg about the ROM image, and also if it is possible to get the ROM chip only.
I don’t have any experience in reading service manuals, so I don’t know what I am looking for. I have attached a picture of the main board in the service manual.
I looked in the service manual and it doesn’t tell you how to flash the ROM. It’s likely possible through the USB port with a computer but Korg would know more about that.
It’s possible your mainboard has a fault and that’s why the ROM failed to write. It could be the ROM itself has failed, the main CPU or possibly something else. Replacing the mainboard would surely fix the problem. You would install the new board (which requires no soldering) then do a firmware update like normal, no special equipment needed.
The ROM IC is soldered to the board so it would be difficult to replace unless you have a technician who can handle surface mount desoldering and soldering.
Before you go panic-buy stuff - please check a few more things first. The Prologue 16 (and 8) use a 15V SMPS that feeds all the circuitry which makes all the voltages required for the unit to run.
The power switch is not a power switch in the usual sense - it requires for the 15VDC from that SMPS to be available. The power switch then turns on a transistor , which in turn turns on all the other stuff. As part of that “turning on other stuff” the power on/off circuitry now expects the CPU to turn on and raise a signal to keep that power circuitry up even after you release the power switch.
I went through the schematics and unfortunately KORG engineering did not provide a simple power LED anywhere to give an indication what is on (or not).
So, after all that - and I do not have a Prologue at hand - can you try a few things:
plug in the power at the mains, have the Prologue in a dark room and push the power switch repetitively and have a look if you can see any of the LEDs on the front panel come on for maybe just a flash - just to hopefully see if the main 15V SMSP is actually working.
If you can’t see anything at all I suggest opening the unit and check that 15V SMPS if it actually supplies that 15V (looks like the picture below) - hope you have and can use a volt meter?
Thank you for the insight! I have not heard anything from Korg yet, and I don’t have the tools or skillset to do surface mount desoldering / soldering or a technician to help me with this, so it looks like the best solution for me is to buy the mainboard from Syntaur.
So I finally took the courage to open up the synthesizer and check it with the voltmeter. I find it scary opening up an instrument for the first time, afraid I might destroy something, but this one is like a 1500 $ paperweight already
I measured the leads from the power supply and it gives 15V as expected, so if you guys don’t have anything else I should check I guess it’s time to order a new mainboard
Next thing to check is the power switch (you’d very annoyed buying a new board just to find the switch is bad) - find connector CN4 on the main board. place the negative lead from the meter to either pin 4 of CN4 or on pinn 3 or 4 on the connector from the power supply. Then place the positive lead of the meter onto pin 1 on the CN4 connector on the main board. You should read about 15V there - then when you press the power switch that should go down to 0V.
Yes! I would be really annoyed if that was the case
So, I had put it back together after the previous test (don’t want the cat playing around in there) but I have tested the switch now. The voltage drops to 0V, and the continuity test through the switch is good.
I don’t have a microscope, and as mentioned earlier I lack both the skills and equipment to do surface soldering, so there is no way for me to find out what’s wrong with the main board. Everything seems just fine looking at it.
Is there anything else I should check before ordering?
