The Fisher TX 50 Amplifier

Hi, this is my first post in these forums. I just hooked up my dad's The Fisher TX 50 Amplifier and started using it (90W amplifier). We hadn't used it for years, and it clips sounds quite a lot. At first I thought it was because I was using my computer's soundcard (M Audio Delta 44, I'm trying to set up a really small home studio, and wanted the fisher amp for monitoring and mixing, etc.), but then I hooked up an AKAI x150d reel to reel and still clipped the sound.
I have two questions: One, I've hooked up the amp to some small, probably 15W speakers (came from a small AIWA stereo, like the ones you get at best buy for 100 bucks. The speakers say 4ohms, and the amp says recommended load 8ohms). Could this be the cause of the clipping?
Two, if this is not it, is it worhwhile to get the amp fixed? Is this a sought after, good quality amp, or is it an average amplifier, and would I do better purchasing a new amplifier?
Thanks for any help! I've looked on the internet and have found no info for this amplifier. I will appreciate any help.

gatomeno

(its serial number is 13180 if that's any help...)

Your receiver is from 1971 and is one of the last original Fisher receivers to be made before Avery Fisher sold his company to Emerson Radio. Any Fisher receiver made from the late 1940's to the early 70's was of quality. Sanyo now owns Fisher today and just sticks the name on a bunch of low end crappy products and hopes some poor sap associates the once great Fisher name with there low end crappy product and think it is still of high quality.