What do I replace it with?

I have a GE Model 25GT500 / Chassis CTC177AA.
The Power went out until I swapped a diode. However, it was not marked and the shematics do not specify the replacement PN. So I just grabbed another diode. It worked and stayed on but the sound was then very low even though it was raise all the way. Here again it recently went completely out. I presume because of the diode taking too much stress.. It lasted several years like this though.. ANY ONE ELSE EXPERIENCE THE SAME THING..?