Have the schematic and the owners manual. Trouble shooting the s-meter circuit stays full scale unit on and setup (rf gain max avc on) antenna disconnected, adjust zero pot no change in meter still full scale. The voltage does drop on the top lug yellow wire from adjusting the zero pot. Should the meter ohm open between the lugs? The voltages are a little high in this unit but my house current runs a little high don't know if that would be an issue, reading 250 instead of 240 for b+ voltage. Trying to determine if it's the meter at fault or an adjustment. Thanks Ira