The power indicator lamp burnt out on my vintage amplifier. The service manual calls for 8v 50ma wired pilot lamp. But I'm getting 18 volts across the connecting pins. I have very little electronics knowledge.
Before replacing it I measured voltage across pins 11 and 8 in the attached schematic. Expecting to get about 8 volts I was surprised to get a reading of 18volts. The resistor is 390 ohm 1 watt.
I attempted to back into voltage drop to see if the 390 ohm 1 watt resistor is the problem, but I'm not making sense out of that. So before I start replacing lamps to have them burn out what should I go after -These components are on a power supply board, which will be a PIA to get at, sits vertically with the business side of the components between the board and transformer.
Other than this problem the amp is working very well, at least to my ears.
Thanks for any help.
Before replacing it I measured voltage across pins 11 and 8 in the attached schematic. Expecting to get about 8 volts I was surprised to get a reading of 18volts. The resistor is 390 ohm 1 watt.
I attempted to back into voltage drop to see if the 390 ohm 1 watt resistor is the problem, but I'm not making sense out of that. So before I start replacing lamps to have them burn out what should I go after -These components are on a power supply board, which will be a PIA to get at, sits vertically with the business side of the components between the board and transformer.
Other than this problem the amp is working very well, at least to my ears.
Thanks for any help.