"bitrex" wrote in message ...

On 05/01/2016 11:14 AM, bitrex wrote:

Haven't had time to work on this project recently due to illness.
I'm back at it.

I'm still trying to figure out the reason that this synthesizer's
membrane buttons keep being non-responsive. Again, there's a
certain multi-wire header that plugs into the main board where if
I tug on it, things function normally. If I let it go slack, the
buttons become non-responsive again. I've cleaned all the
connections, reflowed the solder joints to the headers but still
no luck.

Can anyone suggest a methodical way to isolate where the problem is?


I have a suspicion this might not be a mechanical issue. The connector
I'm actually yanking on is 34-52, on page 18 of the service manual,
labeled "Cartridge Board."

I swapped out a resistor that's connected to ground from the LCD display
to increase the contrast, changed from 5.6k to 1k. That resistor is
right next to IC20, which is connected to the "Cartridge Board"
read/write lines.

I wonder if that bollocked something up, because the synth didn't have
this issue prior to the LCD swap.






Hang on, this is the first we have heard of an LCD swap.

Did you get the new LCD from Roland, and/or is it a part that it known to
work properly in this keyboard?

I smell a Red Herring.



Gareth.