April 2020 – The Imp of the Perverse

Roland Jupiter-4 (JP-4) – Replacing BA662 in Filter

2020-04-252020-04-25 Laban

This Roland JP-4 had one voice board where the filter behaved differently. I had gone through the entire calibration procedure in the service manual but I could not get the VCF Envelope Balance correct. The other three voice boards had no issues. When calibrating the board in question I just could not get it into…

Yamaha DX11 – Repairing Broken Key

2020-04-182020-04-18 Laban

Repairing a broken key of a Yamaha DX11. The key did not spring back up when pushed. This was due to the plastic in the key having snapped and the steel spring had detached. It is quite common that the plastic in these old keyboards becomes brittle over time. If the issue in the video…