Reset function is not working. Hardware issue?

[ptrk.mj]

Hello.

My 5.5G iPod is working just fine apart from one thing. It's not possible to do a 'hard reset' by pressing and holding Menu and Select buttons.

http://support.apple.com/kb/HT1320?viewlocale=en_US

Other key combinations like Select+Play/Pause button to enter Disk Mode or Select+Reverse button for Diagnostic Mode function properly. So do single keys, of course.

I wonder if this might be somehow connected with a click wheel insulation/grounding. Recently, I bought a logic board without a 'silver ground strap' (as described here). Also I wasn't particularly bothered with securing the 'ground tab' (link). I assumed plastic face plate would press it against metal framework firmly enough.

Has anyone experienced anything similar?