korg t2 blown up!

[CTravaglini]

hey there,

i just got a korg t2 in the mail today. plugged it in when i got home and played for about a minute, and the whole machine reset itself. i thought nothing of it, and kept playing, but it did it again. i turned it off and felt the power cabe, noticing that it had a loose fit in tehe socket. i decided that id give it one more try, so i turned it on, played, watched it reset and then heard a pop/crack noise, and saw steam or smoke coming out of the keys!!

does anyone know if this is a common problem, what it could be, if its fixable?

thanks
chris

[billbaker]

smoke = bad

The restart behavior is seen when the power is interrupted for one reason or another.

What is likely to have happened to make the smoke is a short or bad connection that vaporized some metal or maybe plastic.

If the short is in the power lead (the black power cord) it may be due to being pinched, bent, or there being a minute stretch between the wires that would make a spark arc across the gap. That arc can be a huge heat generator... and the thinner the wire the more easily it will burn [example, sparklers and other fireworks are mostly powdered metal like aluminum].

That would be the best possible scenario. For that problem you can try just replacing the power cord.

The more serious problem is if you've fried the internal power supply, and in turn if that has effected the main board.

So try the replacement cord. If everything comes up, dandy.

If not (IMO) it's a shop job. There could be a fault in the plug mounted on the chassis, in the wires connecting to the internal PS, there could be a loose part or screw or something bridging between two exposed wires. And fixing those may not be a guarantee of revival of the unit if there was a power surge or other issue. That is something you can't tell until you open the unit and start poking around. Not a job for amateurs unless you're willing to completely write off your mistakes.

To paraphrase 'Old Yeller', "He's yore dawg, Travis, if you completely FUBAR his motherboard then you're the one's gonna have to toss 'im in the dumpster."


BB[/i]

[T3owner]

I assume that "Perth WA" indicates you're in Western Australia. The line voltage there is about 240 VAC. Since you got the T2 "in the mail", where did it come from, and what line voltage is it meant to run on?

Korg had three different power supplies for the T-series models. Two of them (for the US/Japanese and Canadian markets) run on about half the voltage commonly supplied in WA. The third one is for 220/240 VAC operation. If the T2 you obtained was meant for about 120 VAC, but you ran it on 240 VAC, that might explain what happened.

[CTravaglini]

ah wow. thats not going to be fun!!

i bought the keyboard in sydney, and it has 240v stamped on the back of the keyboard. I'm wondering if the guy has actually altered that label though, because it does sound like running 240v through a 120v machine. i'll be calling the repairer today to sort out whats going on.

also, opened it up last night, couldn't see anything myself, but also didn't really have the confidence to start taking the boards out to work it out!!

[T3owner]

Let's hope nobody was intentionally misleading you. However, just in case the issue I raised is a valid one in your case, I'll provide some further information.

The power supply board should be marked - details as follows:
KLM-1374 = Japan/UL (Japanese/US model)
KLM-1375 = CSA (Canadian model)
KLM-1376 = 220/240 VAC

Only the KLM-1376 is designed for 240 VAC.

Best of luck.

[michelkeijzers]

I know from newer Korg that even although the label was stating e.g. 120 or 240 V, the Korg could handle both voltages. This has to do with country rules regarding displaying only the country's voltage.

But since the T2 is not that modern, I should ask Korg support.

[T3owner]

I know from newer Korg that even although the label was stating e.g. 120 or 240 V, the Korg could handle both voltages. This has to do with country rules regarding displaying only the country's voltage.

Recent products from many manufacturers (not just Korg) have switch-mode power supplies that can work over a wide range of AC voltages.
 

But since the T2 is not that modern, I should ask Korg support.

Or, you could just trust that I already provided accurate information.

[Carlb1058]

Chris,

Hopefully you can fix it but if it's terminal as in totally kernackered would you be interested in parting it out or selling it whole?

I'm in Sydney so it'd be coming home

[jhulk]

its a known problem

its a switchmode psu

but they have specific inputs on these they dont have a switching circuit with a transformer

so that it can be any voltage

the problem is for the 12v they use a zener 12v diode this feeds a temp resistor that cuts the current this over heats and burns the pcb

now the pcb becomes brittle and you get cold solder joints around the switching circuitry

im in the process of having uprated pcbs made using fibre glass less prom to burning and having bigger tacks produced where the tracks burn out it will have a switching circuit transformer a 2 x 110v input which can be switched to either 110 or in series to 220-240

it will also be a linear supply which has less things go wrong

also having new pcb for the ws1 keyboards as the pcb is to thin and cracks

i will keep you posted

there is temp fixes that can be done by adding through hole rivets and wiring wire rap cables to beef up the tracks and by adding a heat sink on the temp resistor so that the heat dissapated does not burn holes into the pcb

[KevJ76]

Hi I know this thread is now 10 years old, so it's a bit of a longshot.
I have a korg T3 with a defective power supply & in need of repair.

You mentioned a replacement pcb, did you ever produce one?
If so I'd definitely be interested.

Kev

[yoshi88]

Hi I know this thread is now 10 years old, so it's a bit of a longshot.
I have a korg T3 with a defective power supply & in need of repair.

You mentioned a replacement pcb, did you ever produce one?
If so I'd definitely be interested.

Kev

I might still have a T3 power supply