Re: [Discuss-gnuradio] A rfx2400 is down, which chip on the borad is broken?

[Lin HUANG]

Hi everybody,

 

I'm the colleague of Hanwen. Today I checked the broken board. I need your help especial Ettus' help.

 

We can assure that the mother board is OK, because when we plug other rfx2400, it works well. For this broken rfx2400:

 

1. The switch control signal, U204 7404

A1 B1 A2 B2 : 0 1 0 1

It seems no problem. And 3.3V voltage is normal.

 

2. The TX side: For the power supply circuit, U111 ADP3336 has input 6V and output 5V and U110 has 5V input and 3.3V output. For the AD8349, VCC=5V, and ADF4360 has VCC=3.3V. They all seem normal. But when we run the transmit program, the graph always stops immediatly and there is no any error report on screen. I'm very confused with this.

 

3. The RX side: the power circuit U6 has 6V input and 5V output, but U5 cannot output 3.3V. So U3 ADF4360 has no power supply. If U5 is the reason for board broken, I can try to replace this chip.

 

But I'm not sure the broken chip is U5. I remember Ettus said that the TX and RX path is completely indenpendent. Why our TX path doesn't work either? Untill now we have already broke THREE rfx2400s, all with the same problem. I worry about other boards will be broken too.

 

Can anybody give some advice? Thank you very much!

 

HUANG Lin

 

2007/5/15, hanwen <address@hidden>:

Hi,

One of our rfx2400 seems not work. I've tested for a while and found:

 

1. the board can be identified by motherboard

2. when I plugged the db to motherboard and run some scripts, I found there aren't any samples come to PC through USB cable. (no wave but a blank on usrp_oscope.py)

3. the TX doesn't work either

 

I doubt there is something wrong with the controlling circuit of this db and the RF analog part is OK. I'm really a layman in hardware, can you give me some idea about which part is possibly broken, so I can exchange them to repair.

 

Thanks!

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