Need Help on 1988 Zenith

[jstout66]

Hello,
I have a 1988 Zenith with an annoying problem I need help on. It's an odd set by the way. I think it's a hotel set, as a sticker on the back states it's a "Zenith Horizon Series" for institutional use. It's model number: H1963S

The main problem is that it has an annoying buzz in the sound. Not on every channel, but on most.

What adjustment can I make, and what module would I do it on? I'm not familiar with "newer" stuff at all. Is there an AGC control somewhere?

Also, another problem is that you cannot use the channel up/down buttons on the set or remote. You can enter them in directly, but if you try to scan up or down, the led readout comes up "PO" and will not change the channel.

I would normally pitch a set like like this, but it has an interesting look to it, and a fantastic picture.