There are no replacements for the MD9162 that I am aware of. You listed your radar as a FR8052, but I assume you actually have the FR8051. If this is the case, and you have a faulty MD9162, you can send it to Furuno USA in Camas, WA so we can determine if the modulator is reapairable.
The address is as follows:
Furuno USA Inc.
4400 NW Pacific Rim Blvd.
Camas, WA 98607
Put it to the attention of the Service Dept. Include a description of the fault. Also include your name, return shipping address and any phone numbers where you may be reached.