RFX1200 RX Tuning problem


I have an new USRP (sn3361 tested on 12-Mar-2008) and a RFX1200 (which
in fact is a factory modified RFX2400 board) which I bought about two
years ago but only until now I’m playing with.

It is recognized as Flex 1200 Tx MIMO B (and of course Flex 1200 Rx MIMO
B) and the frequency range is (1150000000.0, 1350000000.0, 4000000.0).

Oddly enough there is no 0 Ohms resistor at position R84 and R115.

The board transmits nicely on 1296 MHz no problems there.
However it does not tune anny frequency on the receiver site.
Even usrp_fft.py -R B tells me that tuning failed.

I’ve tried about everything I could figure but no result

by the way on side A there is an antique RFX400 Board with on board
64MHz clocks, this board is doing fine.

Annyone an idea what could be wrong with the RX PLL while the TX PLL is
ok ?