Yamaha SPX90 ii Effects - LCD Glitch Repair
Two SPX90ii units came in for repair. The first one had the common power supply failure (recap recap recap), but the second had a funky LCD. Not much information exists about this repair so I thought I'd write it down.
The LCD initially showed just one black bar at the top. After fiddling with the display and the internet test/normal switches I sometimes observed random Asian/Japanese characters. The characters would sometimes change depending on what buttons were pressed, and the red LED numbers would change, so the processor is behaving itself.
My first instinct is to replace the LCD (spoiler alert - this was needless), so I tried to track one down. I found the Newhaven NHD-0216EZ is almost a drop in replacement. Available in Black on Green and Black on Grey.
It has two extra pins for the LED backlight, so we just ignore them.
AND It works! However the screen still shows a black bar. Dangit
OK So it's not the LCD ... what's the issue then? It took some time but I found that the internal battery had leaked, even though it reads as 3.0V. The super fun thing about battery acid is that it's both corrosive and conductive, which makes repairs lots of fun.
Underneath the old battery, 3 small traces had been corroded away from the leaking acid. I've scraped one in this photo to get a multimeter probe on it. You should measure these traces with the continuity tester to make sure they're bad.
I rebuilt the traces by laying wire-wrapping wire down on the scraped traces.
And then installed a battery holder
After reinstalling the battery, you'll need to do a factory reset by holding Balance and Trigger and applying power. After that she came back to life.
The Asian character glitch seems to be quite common so hopefully this helps save you some time and money.