New LimeSDR mini - RF Loopback Test Intermittently failing

General Discussion
1

Hello,

I just received my LimeSDR mini and made sure that the firmware is up to date before I do anything.
When I first run the quick test, I go a pass, but then after 1 minute after I rerun it I got a loopback failure.

These images were taken 1 minute apart https://imgur.com/a/39LsQyu

If I disconnect it, leave it without power for some seconds and connect it back, I get a pass again.

I use the limesuite from the PPA for Ubuntu 16.04
I made sure to remove the antennas before I run this test.

2

Sometimes the test will start working again even if I dont remove the dongle. But might fail again after a while.

Could this be heat related? Is it normal?

3

If I blow a fan on lime, it is recovering. Do the numbers during the failure look reasonable? They seem a bit extreme. With a fan it takes a few seconds to recover.

4

OK, some additional observations.

  • When I first plug my mini, it draws 0.28-0.3A.
  • When I run the quick test the lime draws 0.42A and stays there even if I close the quick test software. The LEDS will continue to blink only green even after the test. The lime also starts getting quite hot even in IDLE after this point.
  • If I connect the LimeSDR mini without running the test and start using apps like SDRAngel for an extended period of time and then run the test, it will pass just fine.

I’ll run some more checks, but so far it seems that the test itself leaves the Mini SDR in a weird state that makes it overheat. I can’t confirm it. It’s just an observation based on the above.

5

@Zack @IgnasJ thoughts?

6

Hello, just to confirm, this issue is not exclusive to the quick test. I managed to stress the Lime enough to run hot and still throw the error, but it recovered after few seconds of non usage.
This is a heating issue indeed, but the quick test does not make it any easier with the weird state it puts it to.

7

Hi @BlackF,

Check my answer here:

It would be good if you could post Quick Test log file when it fails.

8

Hello, this this the log when I connect it cold

$ date;LimeQuickTest 
Σαβ 15 Φεβ 2020 10:37:08 πμ EET
[ TESTING STARTED ]
->Start time: Sat Feb 15 10:37:08 2020

->Device: LimeSDR Mini, media=USB 3.0, module=FT601, addr=24607:1027, serial=1D588F01B6A2F2
Serial Number: 1D588F01B6A2F2

[ Clock Network Test ]
->REF clock test
Test results: 47682; 60879; 8540 - PASSED
->VCTCXO test
Results : 6710995 (min); 6711157 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 13 0A 16 13 0A 16 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 ]
->Configure LMS
->Run Tests (TX_2 -> LNA_W):
CH0 (SXR=1000.0MHz, SXT=1005.0MHz): Result:(-12.4 dBFS, 5.00 MHz) - PASSED
->Run Tests (TX_1 -> LNA_H):
CH0 (SXR=2100.0MHz, SXT=2105.0MHz): Result:(-12.5 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test PASSED

=> Board tests PASSED <=

Elapsed time: 2.43 seconds

Without disconnecting the board, I test again after 3 minutes (Still fine)

$ date;LimeQuickTest 
Σαβ 15 Φεβ 2020 10:39:58 πμ EET
[ TESTING STARTED ]
->Start time: Sat Feb 15 10:39:58 2020

->Device: LimeSDR Mini, media=USB 3.0, module=FT601, addr=24607:1027, serial=1D588F01B6A2F2
Serial Number: 1D588F01B6A2F2

[ Clock Network Test ]
->REF clock test
Test results: 45706; 58903; 6564 - PASSED
->VCTCXO test
Results : 6711038 (min); 6711200 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 13 0A 16 13 0A 16 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 ]
->Configure LMS
->Run Tests (TX_2 -> LNA_W):
CH0 (SXR=1000.0MHz, SXT=1005.0MHz): Result:(-12.9 dBFS, 5.00 MHz) - PASSED
->Run Tests (TX_1 -> LNA_H):
CH0 (SXR=2100.0MHz, SXT=2105.0MHz): Result:(-12.8 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test PASSED

=> Board tests PASSED <=

Elapsed time: 2.46 seconds

I wait another 3-4 mins without disconnecting the board
$ date;LimeQuickTest
Σαβ 15 Φεβ 2020 10:43:33 πμ EET
[ TESTING STARTED ]
->Start time: Sat Feb 15 10:43:33 2020

->Device: LimeSDR Mini, media=USB 3.0, module=FT601, addr=24607:1027, serial=1D588F01B6A2F2
Serial Number: 1D588F01B6A2F2

[ Clock Network Test ]
->REF clock test
Test results: 45962; 59159; 6820 - PASSED
->VCTCXO test
Results : 6711062 (min); 6711224 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 13 0A 16 13 0A 16 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 ]
->Configure LMS
->Run Tests (TX_2 -> LNA_W):
CH0 (SXR=1000.0MHz, SXT=1005.0MHz): Result:(-49.4 dBFS, -1.75 MHz) - FAILED
->Run Tests (TX_1 -> LNA_H):
CH0 (SXR=2100.0MHz, SXT=2105.0MHz): Result:(-13.4 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test FAILED

=> Board tests FAILED <=

Elapsed time: 2.45 seconds

When using other software without doing the test, the boards cools down quite fast on it’s own

9

Same issue here, now asked Mouser for RMA.

10

I have the same with my Lime SDR mini.
But…that was with the recent PothosSDR-2020.01.26-vc14-x64.
This morning i have downloaded a version PothosSDR-2019.01.26-vc14-x64, and programmed again the lime sdr mini with the lime suite gui.
When i look in lime suite gui i see at device info that the "gateware"version was 1.3 and now is 1.28.
Now i started again the lme sdr quick test again and again and maybe 30 times: ALL TESTS PASSED.
So do not send back your Lime SDR mini but first try this. Maybe a bug in the recent software???