Well, today, once again, I purchased this Korg Triton LE 61, well preserved over time but also defective, it doesn't start.

According to the previous owner, it worked normally, one day it started taking a while to turn on, and then it started taking a while to turn on and stay on for a maximum of 15 minutes and it would freeze, it was necessary to restart to use it... until one day it stopped working permanently. .
He said he didn't try to repair it, but I don't believe that version, who would have a well-preserved piece of jewelry like that and not try to repair it?
I think he tried to repair it but couldn't, so he gave up on it.

The device is not yet in my hands, but it will be delivered to me soon. If anyone has any tips on repairs for this model, I'd be happy to exchange information.

The device turns on, but the screen is completely blurred, no sound is made and no button lights come on. In other words, the display simply lights up without letters and nothing else happens.

Soon, once it's in my hands, I'll post more details and the progress I make on it...

Now there are 3 old keyboards that I have on hand to play with and try to bring back to life.... It would be a beautiful machine to compose my studio and my live performances at my church...

That sounds a lot like the smoothing and/or filtering capacitors of the power supply. On a 25-year-old device it's a good idea to just replace them if you're going to be in there poking around -- service lifetime for these large electrolytic caps is ~3000 hours. I'm attaching the service manual for the Triton LE which has parts lists, diagrams, expected power supply voltages and some troubleshooting guides.

Why is your avatar nude?

I also bet for power supply capacitors. Triton runs from external 9VAC brick and has internal AC-DC circuitry. Check 9VAC input and output +3.3V, +5V, +9V, -10V. I bet you have insufficient +5V.

Cheers!

S

Thank you very much, it will be very useful. I bought a soldering iron for SMD in China, that tweezers model, I believe it will help me a lot in this work, I am researching the purchase of a digital microscope to be able to visualize the tracks with greater clarity. Thank you very much.

I'm not, I'm just shirtless.... lol
But I will change soon.

Thank you very much, I will check carefully.

Well, the korg has arrived!

It was delivered to me yesterday at my house and last night I took it apart to see what awaits me... what will be my headache... hahaha

So, here's the video of what he's like when he calls.


https://youtu.be/27TzztBSGDg?si=DJM8ccz9shj9WR-D





Another thing, these memory slots, is it mandatory to have them installed? Mine didn't come with them.

Can I use PC memory?
Because I believe I have memories of this time stored somewhere, I need to look for them.

When disassembling,
I noticed a lot of traces of capacitor oil everywhere, but I haven't found any corroded pads yet, I didn't have time to analyze everything, but I already saw that I will need to wash this board very well with water and neutral soap, then give it another bath with isopropyl alcohol and finish. with contact cleaner.

Then start changing the capacitors and look for more faults or problems.

I checked the source and it is delivering 11.7V AC to the keyboard input, and when I turn it on, the switch turns off both the source (traffic) and the keyboard board buzzing, a buzzing noise. I didn't find any trace of a burst component or damage caused by burning. But I noticed rework already done on the chips, a trace that they had already been re-soldering the chips along the board. I hope you are well.

I find this voltage of 11.7V strange, as the triton has a declared input of 9V AC, but it may be that with load the 11.7V drops to 9v, stabilizing the voltage.

Now the next step is to power the board and check whether the voltages of 9v, 5v and others are present as per the manual, and from then on look for the solution... let it begin then!

Below are the photos... at the moment.

Yes, it's standard PC memory -- 32MB, 72 Pin SIMM, no parity, 11-bit addressing (8 chips, not 2 or 4), 60ns or faster, such as:

https://www.ebay.com/itm/134144004476

Tritons can only support 96MB of RAM.

Looking at your other posts and the thing you mentioned earlier about buying an SMD soldering iron and the leaking caps -- this is important: if you don't have experience desoldering and resoldering through-hole electrolytic capacitors, please please PLEASE FOR THE LOVE OF EVERYTHING HOLY get some trashed electronic gear and practice, practice, PRACTICE. I had a conversation with a guy trying to replace the caps on his Roland JV boards, and he'd never even held a soldering iron. I (and others) urged him to practice, but he was way too eager and stupid to heed the warnings, and he completely trashed two boards before he got lucky with the third. I left that conversation and put it on my "ignored threads".

60/40 or 63/37 leaded rosin-core solder, a solder sucker, solder wick and a 30-watt iron should be all that's necessary for this operation. Also, cleaning your board really well with 90% (or greater -- I use 93%) isopropyl and a toothbrush prior to soldering on it will cut down on that horrible cat urine smell the electrolyte makes when it burns. Make sure to clean all the rosin flux when you're finished soldering.

Yes, thanks for the tips. I have a degree in electronics and work with industrial automation, traditional iron welding techniques won't be much of a problem for me. I bought the SMD soldering iron because I also have a Roland XP50 that I will try to restore later too, and its capacitors are made of aluminum bodies in the SMD standard, and for this the iron I bought will be used. Before I opened this korg last night I hadn't seen that this board uses traditional electrolytics, for me it should be SMD too, but that's not the case. But that doesn't bother me either. My real concern is the source voltage which is 11.7v at the plug output. And also the hiss that the power supply and motherboard make when you turn on the Power button, not only sizzles but also vibrates. A kind of resonance. Well, thanks for the tips, I hope you can help me a lot.

11.7VAC from 9VAC transformer is fine. They always give more than rated and it depends on input voltage. Also, higher load will make more voltage drop. That's normal.

This is multilayer PCB (4 layers I think). It's not easy desoldering thru hole caps because lot of heat dissipation on inner layers. Use proper desoldering iron/tool, high temperature and copper braid. Taking it out is more less easy, but then sucking solder out of holes can be pain. Be careful not to damage PCB.

S

Thanks for the tip,
Multlayer boards are really tedious to desolder.
I myself have had some anger in my life with them, I will use a soldering iron with a finer tip with greater power and I will use soldering flux to try to alleviate the activity.
I'm getting ready to do this job over the weekend, I bought the capacitors and I'm waiting for them to arrive...

Continuing, yesterday I found an old cabinet from an old pentium 133 stored in my place of magical things... hahah, a room in the house full of old machines...
I found 2 72-way SIMM memory sticks with 8 memory chips each, as the colleague above indicated, so I already tried to get them and install them on the triton board, if it works I don't know, we'll know one day, the size of the memory me too I have no idea, I haven't come across this technology in a long time and I forgot how to identify it, I believe it's 8mb per stick.

Little by little we are putting things right...

I used to have a lot of those kinds of issues, and then I made my own "Okie engineered" desoldering pump out of an old Radio Shack desoldering tool, some silicone tubing used for windshield wipers on race cars, and a used footswitch-activated momentary vacuum pump, which works surprisingly well.

I've got one of those!

The pics show HY5117804B Hyundai chips, so those are 16MB non-parity EDO SIMMs. They should be ideal for your purpose.

That's good, I hope it is, that it is then!

Tonight, after I get home from work, I'm going to give this motherboard a nice bath with soap and water, dry it and leave it ready for next Saturday.

Walking...

Yesterday the capacitors arrived.

However, I didn't have the time available to start cleaning the plates.
One thing I noticed is that the button plates are very deteriorated, visibly have broken and corroded tracks.

The funniest thing is that the motherboard, despite having hollow pacitors, does not show visible corrosion, I think it has to do with the quality of the varnish between the 2 boards.

But tonight I will get it cleaned up to prepare for the repair attempt.

Home I managed to clean the board.
I washed it with water and neutral soap, then placed it in the sun to dry and finished cleaning with isopropyl alcohol.

With the motherboard removed from the housing, I fed it to the korg power supply and tested the voltages according to the service manual.
In the photo below I circled the voltages found. The voltages of +3.3v, +5v and +9v are correct and that's why I circled green.
However, the 2 voltage points of -10v are finding -14v. I don't know if it's because the other cards aren't connected, but I found this value strange.

I started changing the capacitors, I changed most of them, especially those on the lines where there should have been -10V and which I had found -14v.

After changing the capacitors, I took the measurements again and all the voltages that were already ok remained ok, +3.3v, +5v and +9v. However, the -10V voltages that were previously found to be -14v rose to -14.8v.

Does anyone have any idea what could be happening?
I checked and still didn't find any open or shorted diode.
There are no signs of damage to the chips, and I haven't found any open trails yet.

If anyone has any tips, I would be grateful.

Is that directly from the power supply or after some board circuitry?

The source provides 10v ac. It passes through inductors and capacitors, and is around -14.8v. Where in the drawing it indicates -10. I don't know if it's a problem or if it's normal.

Another weekend passes and I still don't have much solution for my triton.

I've already looked for why there are -14v instead of -10v and I still haven't found the solution.
Still looking for the reason for this.

At the same time, I'm looking for a used motherboard to buy, however it's difficult, I even found a supplier who says they have it, but the value exceeds the market value of the triton itself if it were working, so I won't buy from him. Unfortunately, there are people who take advantage of the situation to sell items at ridiculous prices, and it's a shame, because I want and will repair my triton, I just don't know when...

moving forward and one day it will work out.

When you say -14V you menan -14VDC or VAC? Quick look at schematics and I think it's unregulated DC negative voltage for opamps and maybe negative voltage for LCD - in that case -14V is OK. I think Triton should boot with only +5VDC and +3.3VDC but can't show picture on LCD if negative supply is missing (no contrast) and no sound output if opamps missing negative supply.

Take any opamp in analog section and measure if positive and negative supplies are present and OK. Also, measure if LCD gets negative voltage (I don't remember which pin)

Btw, describe exactly behavior of Triton when you turn it on. LEDS? LCD? What happens when you press switches? Etc... Does it respond to anything?

Cheers,

Suad

Edit: now I see it has nonstandard LCD I never seen. Don't touch the LCD, they seem fragile.

Thanks for the answer.
Well, the video below was recorded itself, here I demonstrate what happens when I turn on the keyboard.
The LCD turns on with the pixels messed up, nothing else happens, no buttons light up and there is no sound.

The power supply is giving me 9VAC at the keyboard input, as it should be.

In the photo below I list the voltages I found according to the original repair drawing. I find +3.3vdc, I find +9vdc and +5Vdc. but where I should find -10VDC I am finding -14VDC.
So I don't know if this difference from -10 to -14, that is, 4V difference would be a problem.
All the capacitors were replaced and I haven't found any broken tracks yet.
I just installed 2 16mb memory sticks, I haven't done anything else to the keyboard since it arrived to me.

If you have any tips on what to look for on this board to try to repair it, I would be grateful to try.

Watch the video I posted at the link below to understand how the keyboard is behaving when turned on.

https://www.youtube.com/watch?v=27TzztBSGDg

Thanks for the answer.
In my last post I try to answer your questions.

I watched the video. Black visible horizontal bars means LCD has correct negative voltage supply, no problem with that. White vertical stripes suggest LCD is bad as common failure with Tritons. But, that is now least of your problem.

I think all power supplies are correct and that you should start advanced troubleshooting - check if all CPUs get correct clock and reset signals, check activity on data/address bus, etc... standard procedure. However, this is complex board and need expert knowledge. Not to mention lack of parts if something big is the issue.

Cheers

S

Can you give me a technical tip on what to look for first? Where and what should I find?
I can try to do it, I don't have an oscilloscope available at the moment, but I can try to find it with my multimeters.
If you can give me tips on what and where to look, I'll do it and maybe I'll find the problem.

Well, this is highly integrated board, troubleshooting this is not easy even for advanced synth tech.

I took a look at diagram. Triton LE has CPU and 4kbit eeprom that is kind of low level boot flash. If this code is corrupted, synth will not start at all. If boot is OK, then there is RAM and FLASH for system. If system boots and loads os, CPU will start communicating with DSP that has its own sound ROM and RAM. CPU runs from 8MHz clock and DSP from 24MHz and 3.3V. You need decent scope to measure that.

I would do the following - check if CPU and DSP get correct clock. Check if there is some low level boot mode to reflash main OS from smart media card. It is possible that everyithing is good with synth and it just need reflash because code is corrupted. Also take magnifying glass and check carefully legs and solder of all crucial ICs (CPU, FLASH, RAM, ROM...)

...also check positive and negative coltages for any analog ICs (opamp) to confirm supplies are ok

S

What is the way to do this reflash?
Is there any way via memory card?
Or just connecting the pins on the face of the component?

If so.

I don't know, I never worked on triton. This is all my assumption. If boot flash is OK, then I suppose you can reflash main FLASH from card. If boot EEPROM is corupted or bad, most likely you must take IC out and replace then reflash using programmer.

Did you try initialization?

Initialization: Hold Enter and 0 while turning it on

There is a Triton LE on Ebay now for 150US. Sold as is, its beaten, scratched, missing parts but shows successful boot and preset browser on LCD. Also LCD looks functional without vertical stripes. US seller. I think that is your best route...