LCD blank, no data going to LCD, need help

Hello there,

I've had my TI kb for many years now, never had any issues with it. Today I turned it on, and the LCD lights up but nothing shows on it. Nada, zilch. Sound works but has some slight hissy/bleepy noise in the background.

Since it's long out of warranty I took a look at the mainboard (which has a few bodge wires and components hand-soldered on it), and measured whether the LCD is broken. Nope, no data going to the LCD. In fact, the negative supply voltage on Pin 3 of the LCD should be -4V according to the datasheet, but it's +3V.

Took a few snapshots with the thermal imager, the two LM2575S and the two large inductors between them get really hot, so hot that you're actually burning your finger. I noticed that there are some large copper pads and vias for thermal transfer around the LMs, so my question is... is it normal for them to get searing hot? Do you guys (or support) have any experience with problems like this, and is there a common fault that usually develops after some time?

Here's the thermal image in question. The diode gets hot rather immediately, the cap takes a bit longer to heat up.
Now frankly, I'm not very confident to solder around on that board, there's very little space and it's a pretty expensive device at the end of the day. I just hope I can send in just the mainboard in for repairs, instead of having to mail the entire keyboard x.x

[Blockierte Grafik: http://i.imgur.com/bcN7UOs.jpg]

Just to get this out there: Access support responded to me on a Sunday (!), sending me to synthesizerservice.de as well. I phoned them up on Wednesday, they guy on the phone was very helpful and pretty much told me that yes they can look at it, but he suggested that I fix it myself to save postage cost etc. Now the question lingering in my mind was this: What if I replace the filter capacitor. which is the part that gets the hottest (up to 100 C), and there's still a short somewhere after the regulator?
Talking with the service guy pretty made it pretty clear that if there's a short further down the line, there'd be no reason for the capacitor to get so hot.

So in the end I broke out the soldering iron. And promptly peeled off the goddamn pads in the process because they are connected to the rest of the stuff by a thin 0.1 trace. So there I thought, great, I ruined it.
But then I saw that the two 470uF capacitors (of which one got hot) are just connected in parallel. And those are just filter caps. So I measured the voltage and it turns out it's smooth enough even with just one filter cap.

And lo and behold, the display comes alive again.

Did some thermal pics to verify. And because thermal pics are cool

[Blockierte Grafik: http://img9.imageshack.us/img9/5607/7bzz.jpg]

Both the LM and the diode are now as cool as the other side of the pillow. So how about the rest of the board? Well..

[Blockierte Grafik: http://img694.imageshack.us/img694/2919/99ok.jpg]

Interestingly the second DSP is pretty cool compared to the first one. Seems they are not both doing exactly the same stuff. Or perhaps the other DSP only handles part of the polyphony that the first one can't fit anymore. Either way, interesting to see.

[Blockierte Grafik: http://img441.imageshack.us/img441/836/igu5.jpg]

Also there's a little transistor that's getting rather hot...

[Blockierte Grafik: http://img580.imageshack.us/img580/8643/vah2.jpg]

...which is the reason why from now on I'm always disconnecting the virus from mains power completely. Unnecessary? Maybe, but I don't think that little guy has to bear all that heat while the synth is not doing anything. Finally, the other side of the main board with the LCD.

[Blockierte Grafik: http://img209.imageshack.us/img209/2497/h9qt.jpg]

So yeah, bottom line: Virus works again. Thanks for the pointers (and the super quick reponses) flabberbob and Access Support! And also thanks to synthesizerservice.de for the over-the-phone support!

[Blockierte Grafik: http://img268.imageshack.us/img268/5416/crjg.jpg]

Good catch! Bach, Wohltemperiertes Klavier 2, BWV 847

Actually the caps they used on the board are really good quality ones. They're rated well above the usual "crapacitors" you find in consumer flatscreen TVs and such.They are also not getting very warm at all and there's ample room between them and the warm-ish parts (47C is not terribly hot for non-cooled components in my book).
I'd say this was probably a one-off really, and you definitely don't want to solder around a lot on that board as the pads are really fragile.

On the plus side, I now have a new 32.2 Ohms resistor that's just begging to be used in some circuitry as a decoy-component to make people scratch their heads in confusion