Loopback TX_1 -> LNA_W failed

#1

Hello,

The LimeQuickTest TX_1 -> LNA_W give me the following results:
[ RF Loopback Test ]
->Configure LMS
->Run Tests (TX_2-> LNA_L):
CH0 (SXR=800.0MHz, SXT=805.0MHz): Result:(-15.4 dBFS, 5.00 MHz) - PASSED
CH1 (SXR=800.0MHz, SXT=805.0MHz): Result:(-17.6 dBFS, 5.00 MHz) - PASSED
->Run Tests (TX_1 -> LNA_W):
CH0 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-19.8 dBFS, 5.00 MHz) - PASSED
CH1 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-22.7 dBFS, 5.00 MHz) - FAILED
->Run Tests (TX_2-> LNA_H):
CH0 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-17.4 dBFS, 5.00 MHz) - PASSED
CH1 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-16.4 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test FAILED

=> Board tests FAILED <=

Is this a serious Problem? I can’t see any damage.

Regards Ben

#2

Hello everyone,
Could this fault caused by the HF mod done by Lime (LN54 - RX2_W)?
Do I have send it back or is this normal (-22.7 dBFS) after that mod?
Regards Ben

#3

Hello,

I have the exact same issue.

I noticed however that all tests pass when i disconnect the antenna from TX1_1.
Can you reproduce ?

Anyone could confirm that limesdr-usb is supposed to pass all tests from LimeQuickTest ?

Thank you
Regards,
Fred

#4

Hello Fred,
The first time without a antenna all the tests passed.
But after I connect the antenna again the loopback test failed.
After this test I disconnect the antenna and I would expect that all the tests would be passed now but that was not the case.
It doesn’t matter on witch port the antenna is. No change.
So after one time passed without antenna connected the fault situation is the same again.
Strange problem…
Regard Ben

#5

Update:
It looks like the problem start a short time (1 a 2 minutes) after a the limeSDR is connected.
Only just after startup there is no problem.
Maybe temperature related ?

#6

@pe2ben mine fails even on cold boot.

@andrewback hello, could you please advise ? We seem to have a hardware issue since the basic QuickTest fails.

Thank you
Regards
Fred

#7

@zeewox, sure, we will need @zack to make sure that we have tried everything possible and, if it really does look like a hardware problem, arrange RMA.

#8

Hi @zeewox,

Test it using LimeQuickTest and share the result, please.

1 Like
#9

Hello Zack,
what can you tell me regarding my output from my LimeQuickTest above?
Regards Ben, PE2BEN

#10

Hello @Zack,

here’s the result from LimeQuickTest :

[ TESTING STARTED ]
->Start time: Sat Feb  2 00:13:13 2019

->Device: LimeSDR-USB, media=USB 3.0, module=FX3, addr=1d50:6108, serial=00090726XXXXXXXX
  Serial Number: 00090726XXXXXXXX

[ Clock Network Test ]
->FX3 GPIF clock test
  Test results: 65211; 3431; 7187 - 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 : 5112947 (min); 5113081 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 07 19 12 07 19 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_L):
  CH0 (SXR=800.0MHz, SXT=805.0MHz): Result:(-16.9 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=800.0MHz, SXT=805.0MHz): Result:(-18.1 dBFS, 5.00 MHz) - PASSED
->Run Tests (TX_1 -> LNA_W):
  CH0 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-18.3 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=1800.0MHz, SXT=1805.0MHz): Result:(-24.6 dBFS, 5.00 MHz) - FAILED
->Run Tests (TX_2-> LNA_H):
  CH0 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-17.9 dBFS, 5.00 MHz) - PASSED
  CH1 (SXR=2500.0MHz, SXT=2505.0MHz): Result:(-16.6 dBFS, 5.00 MHz) - PASSED
->RF Loopback Test FAILED

=> Board tests FAILED <=

Elapsed time: 2.54 seconds

I’ve tested different computers (Windows and Linux), and even tried to downgrade LimeSDR FW, but the problem persists.

Thank you for your help.

Regards.

#11

Hello Zack,
Do I need RMA or is this ok?
Regards Ben

#12

@andrewback or @Zack,

Please could one of you answer my question.

Regards Ben

#13

Hi @pe2ben,

TX_1 -> LNA_W of CH1 is a little bit lower, but your board is fully operational.