Re: [help] Only noise being seen while IQ balance / phase lo / phase hi.


Hi Jose,
i think:
first: IC10
PIN4 - connected to ground, must be 0V. Check why no 0V (bad solder joint, conductor path interrupted, measured correctly ??)
PIN3 is 5V over 750k (r35). If PIN1 is roughly 5V, everything is ok.
IC9B, IC8, IC7, IC6, IC5:
The voltages depend on the voltage of the FST3153 (IC4, PIN7,9). It is best to measure whether IC5/IC7 PIN1 and IC9/PIN7 are ok. I think 2.5V is ok.
The QCX noises, the volume can be adjusted with volume - So IC8-10 works first.
The voltages at IC6.7 suggest that IC5.6.7 also work (2,5V).
Align 8.1: Here about 7030kHz 8.2: 700Hz 8.3: 600Hz 8.4: 800Hz
8.7 Peak BPF: Press Select - loud tone must be generated. If only noise, then the path SI5351 - IC3C - filter T1 - FST3253 or CLK0 / CLK1 is disturbed
(many have faults on the connections T1). Only if a maximum is found with C1, then:
IQ balance: adjust with R27. If there is no minimum, the path BPF (T1) - FST3253 - IC5,6,7 or CLK0 / CLK1 is strongly asymmetrical or defective

If no balance tone is produced, check:
- Is the transmitter working? (use dummy!) -> test for IC1 and IC3
- Connect antenna, change frequency. Is some (weak) reception or just noise?

vy 73 Reiner DL8LRZ

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