i was preparing to check the items listed above [cooling fan, capacitors, and anything else that visually appeard amiss], when it occurred to me to double check my speaker connections, [which i can't swear were good or bad, i just re-dressed them], and as i powered it up the next time, i made certain the volume control was turned to minimum. it now works every time, and i never had to open the case- so, if any of you are getting the f-61 code, i would suggest checking your external connections and start your unit with the volume at minimum before proceeding to open the unit! it was that simple, for me, anyway
david
July 2008