Onkyo SV828 THX runs very warm

I have an Onkyo sv828THX i purchesed tis from the orignal owner and friend. Problem is with just a pair of Grado 125s this reciever gets quite warm, now i have it hooked to a pair of Celestion Compact A s and it has improved only slightly it has a varible load/speed fan that only comes on at power up and then only for a few seconds no Hum no noise just heat.Onkyo is little help when asked they said they wouldn't have the parts because it's to old (1997)this is a perfect reciever and i don't want to cook it. Even tho the Celestions are a difficult load this is a monster. So am i safe or is this 38 pound foot stool in trouble? Thanks Randy