Re: Wacky voltage readings


Alan G4ZFQ
 

I will save the voltage issue on R2 for further investigation.
Charles,

This comes directly from IC11, the regulator.
Checking C43-46, I found that C45 faults to ground on both sides.
This goes to pins 5 and 12 of IC4. You may lift those with a pin. It looks as if the problem is a solder bridge or IC4.

>Of course that’s complicated by the fact that C45 is connected to R9, making it hard to isolate R9 for testing. R9 has a resistance to ground of slightly less than 10 ohms on one side, and 110 ohms on the other.

If the end connected to IC5 pin 6 is 110 ohms to ground then the fault is on the other end. C45, now removed, or something along that track.

Also, current drain idling is about 117 ma at 12.8 volts on the bus.
Seems about right, I do not know what is specified. But something is wrong with the 5V line.

73 Alan G4ZFQ

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