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
Perhaps the pre stage is class A circuitry? I use a Harmon Kardon AVR7200 as a pre and it runs very hot.
I've own one of those...bought it new around 9-10 years ago...as good as it gets, without one problem! An Onkyo best buy that I will keep untill the day it dies.

It's somewhat rare to find a receiver that has both...amp-in and pre-outs.

Thanks to Nuguy as well as Sogood 51 for your input, i have Never seen or heard the fan come on (except at startup) and don't want to damange it Onkyo is of little help.Is the preamp stage class A ? Again Thank You.
The fan turning on at start-up, lets you know that it is in working order should it be needed. If your unit ever reaches some preset temp, it should turn on. As it has not ever done so, more than likely the warmth of the Onkyo is normal.
Thanks to Shiva as well. After talking to a certiied Onkyo Tech i only became more confused He said you cannot trim the bias but he could add a couple of circuits so it runs cooler this makes no sense to change the design to repair a fault that doesn't exist! I know i should just listen. Thanks to all.
if it is still a concern, I have read of some people putting some little after market cpu type fan and putting it in front of the existing fan and exhausting the heat that way.