Title: I Q Adjustment failure
Post by: WD8BXS on 21. April 2020, 16:12:53
Hi everyone.
Have an older V6 on the bench, it will not do IQ adjustments. No change at all in adjustments.
Changed U3a, U19 on RF board, checked all solder joints.
Can a defective codec cause this problem?? |
Title: Re:I Q Adjustment failure
Post by: DF8OE on 21. April 2020, 16:59:16
Everything that is in the I/Q-chain can cause this issue. You can locate the problem best by looking at the signals using a scope.
I would propose the following guide:
1) check if 0°/90° LO is present at mixer
2) check if coupling transformer is connected properly at mixer
3) check if 48KHz I and Q is present at mixer
This must be true for RX and for TX chain. Of course, if all is ok, the problem can be located between I/Q-connectors from the two boards to codec.
Good luck - stay healthy!
Andreas |
Title: Re:I Q Adjustment failure
Post by: WD8BXS on 21. April 2020, 23:49:30
HA!! imagine my surprise when I discovered that R72 was a capacitor instead of a resistor!!!
Thanks for your help and support.
Stay well also.
Chuck |
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