End of life is a good description of the unit. Best to dump it and not put any money into its tubes etc. Otherwise it will drive you crazy, leaving you little time to 'enjoy the music'.
Preamp "Snap, Crackle, Pop"
I recently purchased an Antique Sound USA PA-5 preamp from a fellow A-gon user. I have been enjoying it, and love the sound; however, I recently started hearing some disturbing amounts of noise during playback of quite passages. The preamp uses 12AX7s and 12AU7s for each input and a GZ34 for the output. I have tested with another preamp and heard no noise, so I ruled out my Amplifier (Jolida JD-502P). I'm fairly certain the problem exists on the output, because I tested the preamp by switching inputs at full volume (it was only a test!) and heard the same snap, crackle, and pop on each input. When it was sold to me, I was told the phono input had this issue, but since purchasing, each input has developed this disappointing "feature".