On Fri, Apr 18, 2025 at 11:38 PM, Kai Bouwman wrote:
where are IC 402 and Q508 located? I can't find any mention of them in the assembly manual.
Kai, both are SMT elements preassembled. You will find both checking section 2.2 of the assembly manual. Please take care not to slip with the probe tips and connect pins.
For IC402: please check schematics page 4. Depending on the selected band one of the pins Y0 to Y3 is connected to pin w. Pin w is connected via T401 to 2.5V from R401 and R402. So these 2.5V are connected to one of the pins Y0...Y3. Please check if all the connections to T401 are at 2.5V and also the selected Y-pin.
For Q508: This transistor is blocking the signal path for RX when TXing. Pleas tell the voltages at D, S and G for TX and RX. We will check the function. I saw two broken Q508 when debugging some QMX.
?
73 Ludwig
