RX888 Mk II thermal problems appear to lead to a broken unit

[rrobinet]

After running perfectly for several weeks with Phil's KA9Q-radio SW, last Saturday my RX888 suddenly failed.

The failure mode suggests that one or more of the BGA pins of the the FX3 have desoldered, and a FLIR scan of a FX3 showed it running at 80C, at or above its max temp rating. In addition, even with the thermal pad which connects to the case, the LTC 2208 ADC is running a 100C, also at or near its rating.

Worse, there is no thermal cooling for the FX3, so it seems quite possible that my RX888 failure and those I hear others have suffered, are due to poor thermal design.. Several of us are working to modify a RX888 to address the problem, and I asked Phil to change KA9Q-radio's default sample rate from 130 Mhz to 66 Mhz.

When my next batch of RX888s arrive from ChinaI am goin to add a heat sink to the FX3, thermal tape between the bottom of the PCB and the chassis, and remove the end plates and blow air through the RX888. I would welcome other suggestions and measurements