RF Loopback Test Failed

Projects LimeSDR
1

Hello - I have a newly purchased LimeSDR usb; I followed the installation and firmware/gateware updates without issue, but the RF Loopback Test consistently fails; can anyone diagnose the following?

[ TESTING STARTED ]
->Start time: Thu Sep 12 20:07:51 2019

->Device: LimeSDR-USB, media=USB 3.0, module=FX3, addr=1d50:6108, serial=00090726074D271A
Serial Number: 00090726074D271A

[ Clock Network Test ]
->FX3 GPIF clock test
Test results: 31826; 35582; 39338 - PASSED
->Si5351C test
CLK0: 17554 / 17554 - PASSED
CLK1: 17554 / 17554 - PASSED
CLK2: 17554 / 17554 - PASSED
CLK3: 17554 / 17554 - PASSED
CLK4: 17554 / 17554 - PASSED
CLK5: 17554 / 17554 - PASSED
CLK6: 17554 / 17554 - PASSED
->ADF4002 Test
Result: 10 - PASSED
->VCTCXO test
Results : 5112949 (min); 5113092 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 0C 07 12 0C 07 02
->FPGA EEPROM Test PASSED

[ LMS7002M Test ]
->Perform Registers Test
->External Reset line test
Reg 0x20: Write value 0xFFFD, Read value 0xFFFD
Reg 0x20: value after reset 0x0FFFF
->LMS7002M Test PASSED

[ RF Loopback Test ]
Note: The test should be run without anything connected to RF ports
->Configure LMS
->Run Tests (TX_2-> LNA_L):
CH0 (SXR=800.0MHz, SXT=805.0MHz): Result:(-14.6 dBFS, 5.00 MHz) - PASSED
CH1 (SXR=800.0MHz, SXT=805.0MHz): Result:(-16.6 dBFS, 5.00 MHz) - PASSED
->Run Tests (TX_1 → LNA_W):
CH0 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-18.0 dBFS, 5.00 MHz) - PASSED
CH1 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-27.3 dBFS, 5.00 MHz) - FAILED
->Run Tests (TX_2-> LNA_H):
CH0 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-19.2 dBFS, 5.00 MHz) - PASSED
CH1 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-15.9 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test FAILED

=> Board tests FAILED <=

Elapsed time: 1.51 seconds

That was the original test; now it will not even get that far, with it unable to conduct the RF Loopback tests at all:

[ TESTING STARTED ]
->Start time: Thu Sep 12 20:46:15 2019

->Device: LimeSDR-USB, media=USB 3.0, module=FX3, addr=1d50:6108, serial=00090726074D271A
Serial Number: 00090726074D271A

[ Clock Network Test ]
->FX3 GPIF clock test
Test results: 19707; 23463; 27219 - PASSED
->Si5351C test
CLK0: 17555 / 17554 - PASSED
CLK1: 17555 / 17554 - PASSED
CLK2: 17555 / 17554 - PASSED
CLK3: 17555 / 17554 - PASSED
CLK4: 17555 / 17554 - PASSED
CLK5: 17555 / 17554 - PASSED
CLK6: 17555 / 17554 - PASSED
->ADF4002 Test
Result: 10 - PASSED
->VCTCXO test
Results : 5112952 (min); 5113094 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 0C 07 12 0C 07 02
->FPGA EEPROM Test PASSED

[ LMS7002M Test ]
->Perform Registers Test
->External Reset line test
Reg 0x20: Write value 0xFFFD, Read value 0xFFFD
Reg 0x20: value after reset 0x0FFFF
->LMS7002M Test PASSED

[ RF Loopback Test ]
Note: The test should be run without anything connected to RF ports
->Configure LMS
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
SetPllFrequency: error configuring phase
LML TX phase search FAIL
Failed to set sample rate
->RF Loopback Test FAILED

=> Board tests FAILED <=

Elapsed time: 1.47 seconds

Any idea what could be going on?

2

Hi @Cedar,

Do you have something connected to RF ports during test?

3

Hi @Zack,

No, I have it in the aluminum case, but the antennae are removed.

4

Hi @Cedar,

Contact CS for RMA, please. Sorry for inconvenience.

5

@Zack I will contact them. Thank you for your time in evaluating this error.

6

I would like to contribute in discussion instead of creating a new topic.
Recently I did some measurements with LimeSDR and got all necessary data from antennas. Now I am encountering a problem with

Rx calibration: MCU error 5 (Loopback signal weak: not connected/insufficient gain?)

Ok, well, I just increased gain in my script, but this did not work

I have tried LimeSuiteGUI by pressing Defaults - Calibrate with temperature around 45 degrees, aaaaand… Same error

Then I have tried LimeQuicktest

LimeQuickTest
    [ TESTING STARTED ]
    ->Start time: Mon Jan 13 13:16:14 2020

    ->Device: LimeSDR-USB, media=USB 3.0, module=FX3, addr=1d50:6108, serial=0009081C05C32739
      Serial Number: 0009081C05C32739

    [ Clock Network Test ]
    ->FX3 GPIF clock test
      Test results: 16873; 20629; 24385 - PASSED
    ->Si5351C test
      CLK0: 17554 / 17554 - PASSED
      CLK1: 17554 / 17554 - PASSED
      CLK2: 17554 / 17554 - PASSED
      CLK3: 17554 / 17554 - PASSED
      CLK4: 17554 / 17554 - PASSED
      CLK5: 17554 / 17554 - PASSED
      CLK6: 17554 / 17554 - PASSED
    ->ADF4002 Test
      Result: 10 - PASSED
    ->VCTCXO test
      Results : 5112939 (min); 5113086 (max) - PASSED
    ->Clock Network Test PASSED

    [ FPGA EEPROM Test ]
    ->Read EEPROM
    ->Read data: 13 01 1D 13 01 1D 02
    ->FPGA EEPROM Test PASSED

    [ LMS7002M Test ]
    ->Perform Registers Test
    ->External Reset line test
      Reg 0x20: Write value 0xFFFD, Read value 0xFFFD
      Reg 0x20: value after reset 0x0FFFF
    ->LMS7002M Test PASSED

    [ RF Loopback Test ]
    Note: The test should be run without anything connected to RF ports
    ->Configure LMS
    ->Run Tests (TX_2-> LNA_L):
      CH0 (SXR=800.0MHz, SXT=805.0MHz): Result:(-68.5 dBFS, -10.00 MHz) - FAILED
      CH1 (SXR=800.0MHz, SXT=805.0MHz): Result:(-74.1 dBFS, -10.00 MHz) - FAILED
    ->Run Tests (TX_1 -> LNA_W):
      CH0 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-55.0 dBFS, -20.00 MHz) - FAILED
      CH1 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-53.6 dBFS, -20.00 MHz) - FAILED
    ->Run Tests (TX_2-> LNA_H):
      CH0 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-61.9 dBFS, 5.00 MHz) - FAILED
      CH1 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-56.3 dBFS, 5.00 MHz) - FAILED
    ->RF Loopback Test FAILED

    => Board tests FAILED <=

    Elapsed time: 1.57 seconds

I have no Idea at all which numbers have to be in the test, what does this test means and how can I head at least noise from my RX channels? I am not interested in transmitting at all

Any suggestions would be highly welcome

Best Wishes

Update, I switched Lime off and on from USB3 port and now encounter another error in LimeSuiteGUI

[13:39:06] INFO: Connected Control port: LimeSDR-USB FW:4 HW:4 Protocol:1 GW:2.21 Ref Clk: 30.72 MHz
[13:39:09] ERROR: Tx Calibration: MCU error 4 (SXT tune failed)
7

Hi @Skye,

As per note in the tester log:

The test should be run without anything connected to RF ports

Do you have something connected to the RF ports?

8

Hi Zack,
thanks for your quick reply.
There was just connector between Lime output and SMA, 10 cm wire. It was not connected to anything else.
I have also tried test without those wires, result is almost the same, difference is ±1 dBFS.

9

Hi @Skye,

Then, as I can see from RF Loopback test, all your RF inputs/outputs are damaged. Maybe RF matching network is damaged or LMS7002M itself. Try to inspect the board visually, especially RF area.

10

Hi Zack,
Ok, thanks, I will take a look, but visually there are no damage evidences, maybe microscope could help.

I have tried another LimeSDR, it passes LimeQuickTest, but still generates
[14:08:00] ERROR: Tx Calibration: MCU error 5 (Loopback signal weak: not connected/insufficient gain?)
Nothing is connected to its ports

11

Hi @Zack,
I have the same problem and have been trying to contact CrowdSupply for RMA several times since 22 Feb 2020, but I haven’t received any response at all. All I’ve gotten each time is the automated reply with an RMA number in subject line and a message that says “We have received your support inquiry. A support agent will follow up shortly to assist you.” Their customer service is atrocious! Any recommendations?