Re: QCX 40 NO POWER OUTPUT #problem #40m #qcx40


Alan G4ZFQ
 

. Like IC6, IC7, IC8 pins 2 and 3 are inputs to the amp. I think they should be equal. Same with pins 5 and 6. The manual says IC8 pin 2=2.46 while pin 3=0.65 for
John,

They are equal.
The manual also says that readings were taken using the internal meter of the QCX that loads voltage sources and shows lower readings. Look at the schematic, IC8 pin 2 connects to IC8 pin 7 through 2 47K resistors. Therefore the simple built-in meter reads low because it's input resistance is only about 13K.
Ohm's Law my be used to confirm this.
A modern DVM has 10M input impedance giving readings that are very very close to actual voltage.

73 Alan G4ZFQ

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