LimeSDR mini - possible tx problem?

Projects LimeSDR
1

Hi,

I recently ordered Five LimeSDR Mini and 4 of them are working great under
both Ubuntu 18.04 and Windows 10, but one of them seems to have a problem on
transmit.
Here are the symptons
When running under Ubuntu 18.04 and application GQRX (receive only) the
suspect unit works fine with just a flashing green LED.
However when I run the suspect unit under Windows 10 and application DATV
Express, the green LED flashes but the red is lit all the time and there is no tx signal.
The other 4 units work fine on the same Windows 10 set up and all units have
V1.26 firmware installed. The 4 working units do not exhibit the red led.
It looks as though there’s something not quite right on the transmit side.
I have tried different PC’s and USB3 ports but all to no avail.
Any idea as to what I could do to determine the root cause and ascertain if it’s a hardware or config problem ?
I suspect it’s a hardware problem as the other 4 work fine - but hope it’s a config problem !
Regards Tim

2

Hi @g4wim,

Could you run a Quick test, please:
https://wiki.myriadrf.org/LimeQuickTest

3

Hi Zack

here you go all under windows 10 - some times it passes and other times it hangs at testing LMS702 registers or other times it hangs at RF loop back.
Sometimes the test program completes but reports a fail board.
Very rarely does it pass the tests.

All the other units pass 100% of the time.

Here are the outputs of the testing showing it hangs the program.

Regards Tim

[ TESTING STARTED ]
->Start time: Fri Jul 27 15:22:52 2018

->Device: LimeSDR Mini, media=USB 3, module=FT601, serial=1D40EC17CEF786, index=0
Serial Number: 1D40EC17CEF786

[ Clock Network Test ]
->REF clock test
Test results: 64918; 12579; 25776 - PASSED
->VCTCXO test
Results : 6710992 (min); 6711151 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 06 1C 12 06 1C 02
->FPGA EEPROM Test PASSED

[ LMS7002M Test ]
->Perform Registers Test

HANG UP

[ TESTING STARTED ]
->Start time: Fri Jul 27 15:28:40 2018

->Device: LimeSDR Mini, media=USB 3, module=FT601, serial=1D40EC17CEF786, index=0
Serial Number: 1D40EC17CEF786

[ Clock Network Test ]
->REF clock test
Test results: 13372; 26569; 39766 - PASSED
->VCTCXO test
Results : 6711030 (min); 6711187 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 06 1C 12 06 1C 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

HANG UP

->Configure LMS
[ TESTING STARTED ]
->Start time: Fri Jul 27 15:33:17 2018

->Device: LimeSDR Mini, media=USB 3, module=FT601, serial=1D40EC17CEF786, index=0
Serial Number: 1D40EC17CEF786

[ Clock Network Test ]
->REF clock test
Test results: 63937; 11598; 24795 - PASSED
->VCTCXO test
Results : 6711029 (min); 6711186 (max) - PASSED
->Clock Network Test PASSED

[ FPGA EEPROM Test ]
->Read EEPROM
->Read data: 12 06 1C 12 06 1C 02
->FPGA EEPROM Test PASSED

[ LMS7002M Test ]
->Perform Registers Test
Read(64 bytes) failed
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RegistersTest() failed
->LMS7002M Test FAILED

[ RF Loopback Test ]
->Configure LMS
Read(64 bytes) failed
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Read(64 bytes) failed
Failed to set sample rate
->RF Loopback Test FAILED

=> Board tests FAILED <=

Elapsed time: 8.51 seconds

4

I’ve been doing some more testing and about 1 time out of 10 it works and I see just a flashing green led.

The other times although the green led is flashing the red is continuously lit either at full brightness or slightly dimly.

I have the unit plugged directly into a PCI based USB3 card within my main PC as it seems to work better (albeit 1 out of 10 as opposed t not at all). I suspect it’s drawing more power than the others as it gets measurable warmer on the RF can and the 1.8V supply measures 1.797V whereas the others measure 1.8V. The 3.3V supply is good as is the incoming 5V.

Hope this extra info helps - would like to understand the significance of the red led being lit.

5

I have taken some photo graphs of the faulty unit generating what should be a clean 2M symbol QPSK transmission at 1249MHz alongside one of the other units which works fine.

The faulty unit shows excessive side band noise / glitches along with a steady red LED showing.
On the infrequent time is works then red LED is not lit and the signal is clean.

Would you like to see these photo’s ?

Something very flakey about this one unit out of the five when running the self test and DATV express program.

I think it needs to be exchanged unless you have any other ideas ?

6

Hi @g4wim,

I am very sorry but yes, I would suggest to reach Crowd Supply and ask for replacement.

7

Hi Zack,

despite my best efforts that is my conclusion as well - I’ve contacted Crowd Supply about the process to return it for an exchange. Hopefully I don’t get caught for import duty on the replacement unit :slight_smile: