LimeRFE - No RX signal RWB1000 / HAM bands

Projects LimeSDR
1

I have a LimeRFE that appears to have no RX signal through the WB1000 / HAM bands. I do get a signal through the WB4000 band.

Probing around the board, the problem appears to be around U66, which is an GALI-74+ LNA. I see the input signal on pin 1, but no output signal or DC on pin 3 (it’s 0V). I can see 5V on the topside of L7. See pic here:

Any ideas? Replace that IC? Its datasheet says the MTTF is 500 years :face_with_raised_eyebrow:

Thanks.

2

I’d check out L7 first - there should be 5V at the output of the amp, and there’s zero. That suggests L7 is open or not soldered down.

3

Hi srcejon,

Thank you for your detailed description of this issue.
Based on what you’ve explained, it seems like the possible problems could be:

  1. Issue with L7: It might be broken or one of its two pads is unsoldered.
  2. Issue with U66: It could be damaged if LimeRFE was operated outside recommended conditions.
    Most likely problem is in L7!

To check if inductor is properly soldered or damaged, you can use a regular Ohm meter. If turns out that there’s no broken connection between PIN3 of GALI-74+ and top pad of L6, then most likely you’ll need to replace GALI-74+.

Regards
Branko

4

Thanks. Turns out I needed to replace both the inductor and amplifier.