Yamaha TG-77 Vintage Synthesizer. Condition: display and batteries needed to be replaced. First thing I did was to replace the battery in the extension card. Then I replaced the battery in the TG-77 with a battery holder, so it can easily be replaced next time.
The new holder needed an extra hole on the pcb, but it fits quite nicely. The next thing I did was a reset and all errors were gone, the TG worked well. Now I disassembled the front to get access to the display. I used a modern black and white 5V 240 x 64 graphic display, so the inverter wasn´t needed anymore. I desoldered the ribbon wires from the old display and soldered them to the new one. I found two leaky electrolytic capacitors on the back of the old display.
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!