Roland TR-909 factory reset
24. Oktober 2018
Repair Korg Polysix Analog Synthesizer Reparatur Service
5. November 2018
Roland TR-909 vintage analog drum machine. "No attack" on the bass drum. But also had some more minor problems such as the mains plug, dirt potentiometer etc.
I started to disassamble the TR909 and replaced the mains input jack with a NOS I had in my stock. Then I looked into the schematics to find out, why this TR909 had no attack. Transistor Q5 gave me the trigger signal but Q6 wasn't triggering the noise signal (base). So I looked for bad solder joints or traces. I found these cracks on the pcb.
Simply a connection between these vias wasn't there. So I fixed that with a kynar wire. And voila, now that bass drum has attack again.
Simply a connection between these vias wasn't there. So I fixed that with a kynar wire. And voila, now that bass drum has attack again.
That's it. Roland TR909 is fully working and rock solid. Here are my usual pics I have taken for my own purposes and that I share with you guys.
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!
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.
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