Hello all,
Another electronics repair job here, hopefully something quite simple this time.
I have a little Casio PT80 keyboard instrument as seen below:

When I got it, it didn't work properly because the trim pot used to adjust the tuning (accessed through a hole in the keyboard base) had been damaged. What appeared to have happened was that someone had roughly pushed a screw driver in the hole and ended up breaking the trim pot.

I removed the damaged trim pot, ordered a new one one of the same specification, and then fitted that. Put the keyboard back together again, turned it on and all seemed to be working fine. The keyboard has a main voice selection for playing on the larger keys, and a drum/ rhythm section. There is a master volume control for everything, and a rhythm volume control.
Anyhow, after testing it out for a while and feeling chuffed that the little Casio was now fully functional again, I noticed a constant white noise/ static appearing. This got steadily worse, until it was so intrusive that it made using the drums/ rhythm section impossible, as that was the section that appeared to be suffering from the fault. If I turned the rhythm volume all the way down, the main voice was completely noise free. Furthermore, on first switching on the keyboard the noise was there, but only got considerably louder once the drums were triggered. After that, even when stopping the drums, the noise remained louder.
This video I took gives a good demonstration of the fault:
The keyboard is mostly analogue, almost certainly the entire drums/ rhythm section is. Being a novice when it comes to electronics, I had not much idea of where to look for the fault. However, I took a leaf out of the circuit benders handbook and simply tried grounding some of the components to see if that would have any affect. Surprisingly, I discovered that grounding some components in one section completely eradicated the noise! The main components where a 103 Capacitor, one leg of a 3 legged transistor and one of the resistors. The picture below shows the components circled in yellow, that when grounded got rid of the noise.

I found that when unsoldering and lifting the leg of the C103 capacitor, the noise was gone. I though that I must have discovered the fault, so ordered a bunch of 103 capacitors. I fitted the new capacitor tonight and...
...the noise was still there. Bugger. As there was another C103 capacitor close by that also reduced the noise but not eradicated it when grounded, I decided to replace that too as I had to buy the capacitors in a pack of 10. Might as well remove it and get a bit of soldering practice in. Anyway, second 103 capacitor replaced and still no difference - the noise was still there.
That left the T14 transistor as another likely culprit, as this also stopped the white noise when one of the legs was grounded. I unsoldered this and removed it from the board, then fired up the keyboard with the transistor missing. The white noise was now gone again and everything was working fine! By a process of elimination, I suspected that it could be the transistor that was at fault.
The problem I have now is identifying the transistor. The numbers on it are "603 3ZE".

However, doing a Google search does not appear to come up with much information on it, let alone how to test it. Being a Japanese keyboard I assume this is the JIS standard of marking transistors?
Having got this far, I guess my questions are:
1. Could the transistor be the likely cause of the white noise?
2. If it is, how can I identify it and where can I find a replacement?
Obviously I know that the keyboard is noise free without the transistor fitted, however, I assume it's fitted for a reason. As such, I'd like to replace it.
Hopefully someone can kindly point me in the right direction.
Another electronics repair job here, hopefully something quite simple this time.
I have a little Casio PT80 keyboard instrument as seen below:

When I got it, it didn't work properly because the trim pot used to adjust the tuning (accessed through a hole in the keyboard base) had been damaged. What appeared to have happened was that someone had roughly pushed a screw driver in the hole and ended up breaking the trim pot.

I removed the damaged trim pot, ordered a new one one of the same specification, and then fitted that. Put the keyboard back together again, turned it on and all seemed to be working fine. The keyboard has a main voice selection for playing on the larger keys, and a drum/ rhythm section. There is a master volume control for everything, and a rhythm volume control.
Anyhow, after testing it out for a while and feeling chuffed that the little Casio was now fully functional again, I noticed a constant white noise/ static appearing. This got steadily worse, until it was so intrusive that it made using the drums/ rhythm section impossible, as that was the section that appeared to be suffering from the fault. If I turned the rhythm volume all the way down, the main voice was completely noise free. Furthermore, on first switching on the keyboard the noise was there, but only got considerably louder once the drums were triggered. After that, even when stopping the drums, the noise remained louder.
This video I took gives a good demonstration of the fault:
The keyboard is mostly analogue, almost certainly the entire drums/ rhythm section is. Being a novice when it comes to electronics, I had not much idea of where to look for the fault. However, I took a leaf out of the circuit benders handbook and simply tried grounding some of the components to see if that would have any affect. Surprisingly, I discovered that grounding some components in one section completely eradicated the noise! The main components where a 103 Capacitor, one leg of a 3 legged transistor and one of the resistors. The picture below shows the components circled in yellow, that when grounded got rid of the noise.

I found that when unsoldering and lifting the leg of the C103 capacitor, the noise was gone. I though that I must have discovered the fault, so ordered a bunch of 103 capacitors. I fitted the new capacitor tonight and...
...the noise was still there. Bugger. As there was another C103 capacitor close by that also reduced the noise but not eradicated it when grounded, I decided to replace that too as I had to buy the capacitors in a pack of 10. Might as well remove it and get a bit of soldering practice in. Anyway, second 103 capacitor replaced and still no difference - the noise was still there.
That left the T14 transistor as another likely culprit, as this also stopped the white noise when one of the legs was grounded. I unsoldered this and removed it from the board, then fired up the keyboard with the transistor missing. The white noise was now gone again and everything was working fine! By a process of elimination, I suspected that it could be the transistor that was at fault.
The problem I have now is identifying the transistor. The numbers on it are "603 3ZE".

However, doing a Google search does not appear to come up with much information on it, let alone how to test it. Being a Japanese keyboard I assume this is the JIS standard of marking transistors?
Having got this far, I guess my questions are:
1. Could the transistor be the likely cause of the white noise?
2. If it is, how can I identify it and where can I find a replacement?
Obviously I know that the keyboard is noise free without the transistor fitted, however, I assume it's fitted for a reason. As such, I'd like to replace it.
Hopefully someone can kindly point me in the right direction.