Opened the Palomar 500 12 volt power supply combo. The transformer bolts were so tight I couldn't tighten them. Thay would not turn. Brushed on clear nail polish. . Found the four bolts holding down the transformer were losse, tightened but in the end no help. While it was open I gave the fan a quick shot of electrical contact/lubricate spray. I was shocked to see a few wires with worn insulation. Believe it or not the two exposed wire insulation was that weaved cloth insulation that was used from the 1930's through the early 50's, all other wires were modern rubber/plastic insulation. ok. Here's my question should the fan be sucking air out of the amp, or should it be blowing air in? There's a luvoured cover on top of the amp. The fan is located dead center on the back of the amp. I wanted to plug in the amp and turn it on to listen to exactly where the buzz was coming from but, I know little to nothing about this and didn't think it was safe.