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#qmx QMX is up and running - except 30/20 - UPDATE #qmx

 

Hi Chris,

seems, like everything is ok.



But there is still only very very low output on 30/20.
So, for test I changed LPF-assignment for 30/20 to LPF 1 and there at least I could see a much stronger signal on 30 but very low on 20 (ok, the attenuation ist for this bands unsuitable).
Therefore, there must be an bug in LPF 2 - but I cant' find it (see my initial post about the measurements).
Before I now desolder the complete LPF2-path and renew all parts: Any more helpull hints ?

73 Frank
 

On 19/08/2023 11:03, Frank wrote:
Before I now desolder the complete LPF2-path and renew all parts:
Frank,

Just resolder the inductors.
At least 90% of LPF "faults" are just inductor solder joints.

73 Alan G4ZFQ
 

Frank,
Check L509 for continuity. If it is open, the PIN diodes for that filter will not forward bias.
Also, L510 and L513 must have solid connections as well for the PIN diodes to function on transmit.

JZ KJ4A

On Sat, Aug 19, 2023 at 7:03?AM Frank <dc8fg@...> wrote:
Hi Chris,

seems, like everything is ok.



But there is still only very very low output on 30/20.
So, for test I changed LPF-assignment for 30/20 to LPF 1 and there at least I could see a much stronger signal on 30 but very low on 20 (ok, the attenuation ist for this bands unsuitable).
Therefore, there must be an bug in LPF 2 - but I cant' find it (see my initial post about the measurements).
Before I now desolder the complete LPF2-path and renew all parts: Any more helpull hints ?

73 Frank

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