ctk 1000 CTK 1000 - Left speaker not working

[Stevo23]

Hi,

 

I just got a CTK 1000 Keyboard, working fine, except the left speaker (using Headphones, the same, so left channel). When starting to use the volume fader, I hear a little crackle on the left speaker. That’s it.

I disassembled the keyboard, took out the fader, cleaned it with isoprop., but no effect, just less crackle than before. Before cleaning, there was a volume fader position, right in the beginning of it, when I had sound on the both speakers, unfortunately with a very low volume.

 

Maybe someone has an idea what it could be, any help is very welcome!

 

Thank you 🙏🏽

[Jokeyman123]

Still sounds like it could the fader. I discovered something a few years back that might help if it is the fader, and not something with the amp chip or related components.

 

Restoring an old digital deck with multiple faders that did not work correctly, I had to disassemble the faders completely-taking the ic board off the back, bending the metal retaining clips to open it, here is what I found-nothing else was working to restore several of these faders, and i could not find matching replacements-always better if you can find the part. Very difficult with fader pots as the length and width, plus the pin configuration must match and whether it is linear or logarithmic. Most Casio I believe are linear.

 

Inside, and underneath-there was a tiny bit of accumulated dust and dirt, which no amount of cleaning or air from the top open slot could clear-it was jammed into the upper and lower extreme positions of the slide pot. Wish I had a pic, if I have some time today, I will take one of my spares apart and demonstrate where this was. I cleaned this out with airand some electronic contact cleaner and amazingly enough, these pots worked perfectly again. The Casio fader might be designed differently, but it could be similar. Use a good electronics cleaner on that pot, even alcohol can leave a residue that doesn't work. I was reminded of this recently-cleaning the main pot on an old Alesis Ion with a seemingly defective (but circular) pot. Alcohol did not work, but I sprayed some DeOxit electronic tuner cleaner-I also use CRC both of which will not damage plastic-don't go near anything else! Bam, it works perfectly now. I think this is because most commercial isopropyl solutions are in a  water solution, and the water  or alcohol can leave a residue that prevents perfect electric contact. You desoldered this, check your solder contacts, sometimes excess flux can cause a seemingly good solder joint to fail, and if you did not check for a crack in the original slide pot, this could have been the problem. I don't think a shorted speaker should short out the headphone audio, but anything is possible. Disconnect the speaker and see if the headphone out works.

 

If none of this works, the first components to fail on older electronics will (usually) be the caps, although it is possible for the amp chip (if this design uses a discrete, all purpose stereo amp chip) to fail. You might be able to detect a bad cap visually, otherwise you would have to check individual chips, a little complicated if you don't already know how, whether soldered in place or de-soldered. A capacitance meter (these are now cheap) isn't a bad idea of you need to do this type of work alot.

[Stevo23]

Wow, thank you very much Jokeyman123 for all this great ideas and possibilities of fixing that thing! Im far away of being a pro, so the only thing i could do is to desolder the fader, open it, clean it again well and spray it with a good contact a spray. I used 99,9% isoprop.
I also will try to diconnect the left speaker, if it has any impact on the headphone out.
If it helps, i could post a picture of the fader, but only by tomorrow. 
Again, thanks a lot!!!

i will be back with news and pictures! 
 

[Stevo23]

Here some pictures of the fader:

 

 

 

 

 

 

[Stevo23]

Hello,

 

unfortunately i could not resolve the problem yet. What i did:

 

- desolderd the fader, dismounted, cleaned all parts well and added some Deoxit Fader; put all back together -> still the same problem. 

- disconnected the left speaker to check Headphones OUT -> no change 

 

One thing changed: when i keep my hand near to the Volume Fader now, the “noise floor” gets louder, closer i get with my hand. Like the guitar/pick up thing… (No idea how to describe it better)

I also forgot to mention, that the Left LINE OUT also has NO output. The Right/MONO LINE OUT (yes, here its R/Mono) works , unfortunately coming together with this little “noise” I described earlier, even my hand is now far away. 
 

i tried my best, again, appreciate all of your help! Maybe its time to let a pro do its work! 🙏🏽