Vintage Synth Explorer Forums

I bought a K1r new from my local music shop back in the day. When i first plugged it in and played it, the presets sounded weird, wrong, messed up. There was a lot of cymbal! I'd pick a strings patch and you'd get this warped glitched cymbal thing!

It was definitely not working correctly, so I took it back and they exchanged it for the other they had, and that one worked fine.

I'm guessing some hardware issue with the PCM chips or something causes this behaviour, and it sounds similar to the issue you have...

I did get to speak with one of the guys at Kawai today. He gave me some additional troubleshooting tips and mentioned that, in his experience, it was KTG-003 (the IC that reads the wave ROM) that more commonly causes 1-in-8 keystroke type problems. He had seen this from KTG-002 as well, though.

KTG-002 is still available - about $42.
KTG-003 is NLA.

Complete main boards are also still available, but run quite a bit more than a working K1-II goes for.

So, at this point I'll try his troubleshoot tip - using a probe hooked up to an amplifier to listen to the data lines between the ICs, and, depending on what I find, probably still go ahead with using parts from the K1m to find the bad part in the K1-II. If it is actually the KTG-002, I may fix both... otherwise I'll probably part out the module.

So, here's the result:

I got the "for parts" K1m and verified that it worked, except for a broken joystick.

I got a ROM burner and some new ROMs.

I got a copy of the latest firmware for the K1 II and updated to that (v1.3). It made no difference, but I didn't expect it to... just wanted to have the latest version in there, while I had it torn apart.

I set up the K1m side-by-side with the K1 II and with the K1 II driving the K1m and both set to Bellery so I could compare signals between them. I didn't see any difference in the signals going into KTG-002 on the working K1m vs. the non-working K1 II.

So, I swapped KTG-002 from the K1m to the K1 II. I was pretty happy with my desoldering and soldering work, especially since I haven't done much SMD work lately. No difference, though.

Then I tried KTG-003 (more and finer pins on this one). This is the IC that the guy at Kawai said usually caused 1 in 8 problems. Again the soldering came out good, but again no difference.

Since it was the next most likely candidate, I then tried swapping the 3rd chip - KTG-001, that sits between 002 and 003, and, guess what? That was it. So, I now have my K1 II working fine, and I'll need to check with Kawai whether KTG-001 is available (and whether the price is worthwhile). If so, I'll see about fixing the K1r as well.

Well, the KTG-001 is still available, but it's $88. Not really worth it to repair the K1m, I think.

Cool - thanks for the update!

Given the price of many of those parts, versus what one can actually buy a K1 series instrument for, I wonder if Kawai has a considerable collection of spare parts they'll never sell off.