I have quite a few old MacroTech amplifiers all have similar problems, the amps take time to turn on. the 4 second delay is up to 10 seconds. the amps switch on an off (green to red) for a few minutes before turning on ok. I have changed ribbon cable and connector pins to output channels. all are very corroded at the air intake. some of the amps started to work ok, but when left for a week or two the amp will switch on/off until it seems to worm up. the amps are old 10 to 15 years do i need a capacitor/resistor change. I need to be guided in the right direction if you know of common problems like this.