Korg Poly 800 Trouble Loading Sound Patches

[TastefulFist]

Recently picked up a Poly 800 for quite cheap. It didn't make any sound and the CR2032 was disconnected inside, so I replaced the battery and soldered in a new holder. However, I can't seem to load in the sound data. I have a .wav file with the data and am following the instructions in the manual, but when I press the 1 key to load it immediately goes from displaying TAPE to displaying ERR instead of displaying LOAD. Interestingly enough, if I start playing the file on my computer and then press load, it goes to VRFY, but I've tried a few volumes across a few devices and all of them eventually display ERR.

Possibly unrelated but also an issue is that whenever I'm not in TAPE mode, I can change the current program number but as soon as I press any actual key on the board it resets back to 11.

Is there anything I should try or am being oblivious about?

[TastefulFist]

Discovered something about the second issue where it resets the program. There are two keys in the board which do not cause this (the first two C keys), while the rest do, so I'm guessing something with the I/O is messed up.

[meatballfulton]

All synths that used tape interfaces are very sensitive to the level. Try lowering the volume out of your computer.

[TastefulFist]

All synths that used tape interfaces are very sensitive to the level. Try lowering the volume out of your computer.

I'll give it another shot soon here but I did try a pretty wide range of volumes the first go around. Often the lower volumes would display ERR immediately, while higher ones would get through the entire sound file before they errored.

[TastefulFist]

Haven't had much time to work on this recently but I've come to a few conclusions. I am fairly certain that the synth is not even trying to load the sound patches, and instead the load button triggers the verify action. When I compared behaviors between load and verify, both displayed the exact same things at the same times, and failed at the same times when the volume was set the same on the source. My working theory is there is something wrong with either one of the I/O ICs on the board or some sort of broken/bridged trace somewhere, but I have little to back this up other than speculation.