Sirius 150 - low resolution Nexrad

I purchased a new Sirius 150 Weather Rx last September connected to an E120 display. It worked perfectly after installation. After the winter break, I renewed my weather subscription and the sat weather now works fine except the nexrad is displayed in extremely low resolution. All it shows is large square blocks instead of detailed precipitation radar returns-regardless of zoom level. I had my electronics tech switch the 150 from the E120 to my G series display without improvement.
the P/E is E70161
the S/N is E701610630231
the ESN is 97VX0403
Any suggestions would be greatly appreciated