Re: Help with strange audio fault #qcx


James Daldry W4JED
 

Hi, guys

Let's throw some logic at the target.

My B&K 2405 meter tells me that when my Fluke 111 is measuring the resistance of a 10K resistor it is putting about 0.115 volts across the resistor. In other words, it's not turning on any semiconductors. Especially silicon ones.

Assuming that the radio draws 100 ma on receive, let's substitute a 1200 ohm resistor for the radio, making a network of 2 10K resistors with a 1200 ohm across the open ends. A triangle. The 1200 ohm resistor takes the place of the rest of the radio. If we put an ohmmeter across one of the 10K resistors, then short the 1200 ohm resistor, we will get about 5300 ohms with the circuit "normal" and 5000 with a short across the 1200. So - either the +12 volt end of R40 isn't making the trip or the ground end of R39 isn't.

Jim Daldry W4JED

On 1/15/19 4:12 AM, Alan G4ZFQ wrote:
Battery disconnected
IC10 p5 to ground = 5.33K
PCB battery terminals shorted
IC10 p5 to ground = 5.33K
Just pondering what that means
Ted,

That means look at pin 6.

73 Alan G4ZFQ


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