Any SAE experts here ? Your help would be appreciated. I just acquired a mint condition SAE Mark 24 amp. Both channels are playing fine but one of the power meters is not functioning. I disconnected the meter from its drive board and applied a small voltage to it. The needle deflected full scale, leading me to believe the problem is elsewhere, likely with one or more of the diodes on the drive board.
Hi Glen,
You are on the right track. Those meter movements are 1 mA for full scale deflection at the most. 100 uA is common as well. An ohm meter in a DVM locked a few scales up from the bottom would be safe to test the meter with.
You may want to consider replaced the electrolytic capacitors with new ones on an amp that age. Nice acquisition BTW.
-Chris
You are on the right track. Those meter movements are 1 mA for full scale deflection at the most. 100 uA is common as well. An ohm meter in a DVM locked a few scales up from the bottom would be safe to test the meter with.
You may want to consider replaced the electrolytic capacitors with new ones on an amp that age. Nice acquisition BTW.
-Chris
I just wanted to follow up on this problem. The diodes tested fine. A pin on the meter circuit board to which the output is connected apparently had a fracture (don't know how that happened) and snapped off very easily while I was checking out the board. I removed the stub from the meter board, installed a new pin and the meter is now working fine. I also recapped all of the boards in the amp and it is now singing beautifully.
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