Motorola filter replacement

In order to use the phone as a passive uplink sniffer, you will have to remove and replace the RX filters.

To replace filters on Motorola phones you will need:

• ​HHM1526
• ​HHM1523C1
• ​04025A150JAT2A
• ​04025A220JAT2A

As the shipping cost for such a small-quantity order is relatively high, a complete component kit is

available for online order from ​http://shop.sysmocom.de/products/osmocombb-filter-kit

Remove existing baluns

First you will need to remove existing balun:

Solder new baluns

Clean up the phone and solder HHM1526 and HHM1523C1 on the right places (the black dot goes up):

Solder ceramic capacitors

Last step is to solder ceramic capacitors 04025A150JAT2A and 04025A220JAT2A:

Credits

Thanks to ​Sylvain and Peter who made this possible.