marantz sr-6003 "zone" question

hi all, up until today my zone A speakers were working fine. but now they are not working at all. the only thing i changed was switching from optical cable out on my satellite tv receiver and dvd player to all hdmi. i had read over on AVS forum that the marantz can't operate zone speakers(mine are hooked up to the surround back binding posts of the receiver as instructed in the manual)via digital input. but i know this isn't correct cuz they worked when it was optical(a digital input). before breaking down the whole thing and testing out whether they work again with the optical can any marantz owners offer some advice? thanks a million, d.