Repair Yamaha SY-77 Vintage Synthesizer Reparatur Service27. Dezember 2020
Is your battery still healthy ???4. Januar 2021
Akai AX60 repair. Tuning was unstable, tracking was bad. One note stuck. Buttons were dirty and did not make good contact. Some of these plastic covers were loose. So let's get started...
I often check the power supply first. In this case it was more than right, because some ICs needed a correct negative voltage to work correct. And that was not the case. There was a defective transistor 2SB891. With no load (no note depressed) the negative volate wasn't that bad. But the more notes I played the more the negative voltage broke down. Replacing that transistor solved the problem.
During my testings I found that some switches did not react even pressing a few times. So I decided to replace them with new tactiles. I also fixed the plexiglas inlays.
To make trouble shooting easier I installed 6 LEDs to see, which voice is playing when keys are depressed. After repair I uploaded the factory patches from tape. If you want to load from tape you can watch my IG video. If you have problems loading the sounds play with the level.
There are lethal voltage exposed in electronic devices. Unless you know what you are doing, don’t try this. If you following along, you doing so at your own risk.
I’m documenting repairs for my reference and yours.
I do synth restorations and repair with a specialty in vintage synthesizers, drum computer and other vintage gear, based in Düsseldorf, GER. Get in touch about your synth situation!