Regency R1080 programmable scanner with no ...

I have a Regency R1080 programmable desktop scanner which I bought back in '87. I hadn't used it in a while although it's always been plugged in. Recently, my interest in scanning was renewed so I turned it on, but it is no longer producing any audio. The only thing that comes out of the speaker is a hiss. I've tried adjusting the volume control throughout the entire range; it only adjusts the volume of the hiss. I also tried adjusting the squelch control every different way but there's no effect at all.

Everything else about it seems to work fine. It still scans. It will still stop on a channel when it picks up an active frequency. When there is someone broadcasting on a frequency, the hiss will disappear and there will be just silence. Once the transmission ends, the hiss comes back. I have a handheld scanner that was programmed with the same freqencies so I was able to confirm when someone was transmitting on a frequency.

I also tried tuning it to the Weather Band which transmits 24hrs a day, but there's no audio, only silence. Once again, I used my handheld scanner tuned to the same frequency to confirm that I should be hearing something.

Any ideas on what the problem is with the audio?