Temporal strange noise and no RX after starting (tr)uSDX

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DO1KKA
 

Posts: 5
Joined: 20 Apr 2022, 09:52

Temporal strange noise and no RX after starting (tr)uSDX

Post by DO1KKA »

Dear all,

I have some strange issues with my (tr)uSDX. I have mine from the group buy SN3AK, but changed the Atmega because I burned the chip while assembling it (shortage at SPI connector).
The chip seems to be a genuine chip, at least I got a normal serial-number after I flashed the bootloader.

Here is the problem:
Almost every time I start the device, either from 5V or from 12V, it makes a loud noise (internal and external speaker), shows at all bands constantly about -70 dBm to -90 dBm and has no reception. It makes no difference if there is an antenna connected or not. After some time, the loud noise stops, and the device receives normally, so that I can use it. Sometimes the noise doesn't stop and I can make it stop if I play a little bit with the power/USB-connector, so that it, maybe(?), looses for a short time voltage. Other times absolutely nothing helps and I can't use the device for receive.
I already tried to reset the settings and to upload the firmware again, but that didn't help.

Has anyone had this issue too and found a solution to this weird issue? Or maybe someone has an idea what could cause that issue?

73's,
DO1KKA
Last edited by DO1KKA on 11 Aug 2022, 21:02, edited 1 time in total.
DO1KKA
 

Posts: 5
Joined: 20 Apr 2022, 09:52

Re: Temporal strange noise and no RX after starting (tr)uSDX

Post by DO1KKA »

I uploaded a video on Youtube which shows the behaviour of the (tr)uSDX.
https://youtu.be/IEgDrwG_tVU

I also managed to capture a video where the (tr)uSDX suddenly jumps from the strange behaviour into normal operating mode at minute 0:30. You can also see the dBm jumping from -82 dBm to -105 dBm
https://youtu.be/4qc7Bi_zAUg

After a lot of troubleshooting I think it could have something to do with the power the (tr)uSDX gets. A few minutes after I recorded the second video I made some tests while the truSDX was working again. Connected to 5V or to 12V without RF board the truSDX was working. Connected to 5V with attached RF board the truSDX was also working. Connected to 12V with attached RF board the truSDX had the issue again. After a few minutes the issue was also gone with 12V and the RF board connected. Usually in this state I can use the truSDX for quite some time and the issue only comes again when I leave the truSDX some time (I think more than 30 minutes) disconnected from power.
Could this maybe be an indicator for an damaged capacitor?
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