power supply issues are common on the G68 as far as I know.
replace it, and check for any bulging caps on the pcb boards.

The following repair guides should help :
https://www.Meridian-audio.info/pub...4017,P5d.pdf.pagespeed.ce.xOn_FaqFWq.pdf
https://www.Meridian-audio.info/public/technote_tn20_3_-_g_series_psu_exchange%5b4003%5d.pdf
https://www.Meridian-audio.info/pub...oting_surround_controllers%5b4029%5d.pdf


Hope this helps..