Hmm. If it's not software, and it's not sticky buttons, and you've ruled out stray IR signals (see my other post), then maybe it's a flaw in the switches or the circuit board? Or perhaps a problem with the connector that connects the display panel to the rest of the unit?

Here's a stab in the dark: Hugo, where is the de-bounce circuitry located? Are the buttons de-bounced in software or hardware? If hardware, is the circuit on the display panel or the main board?



-- Tony Fabris -- Empeg #144 --
Caution: Do not look into laser with remaining good eye.