I've had my dx90 since July with no issues or the dropout problem that has been reported. Thought I was lucky until recently. Since its under warranty I reported my problem to the vendor to get it fixed. Here is the problem I just reported to the vendor in case anyone has a similar issue:
The problem I have is intermittent and has happened in the last 7 days or so. It definitley occurs when the unit has been on for more than 10 minutes. The audio/power cuts off for a few seconds. The screen returns first and during that time the battery meter is blank. When audio returns a few seconds later, it is filled with static/screechy. Sometimes the volume returns at a real high level for about a second and returns back to it original volume. This can happen multiple times in a row. During this time, when I apply a little pressure on the sides of the unit by the bottom corners of the screen, the volume cuts in and out. It can also happen when I touch the top and bottom of the unit. It does not happen when I touch only one side. I have the silicon cover on the unit.
I am using the latest FW version 2.1.5. I've loaded it multiple times according to the directions(copy update to the unit, system update, factory reset and remove update file). I've tried different microsd cards(exFAT and FAT). It occurs with music on the microsd and internal memory. I have also reseated the battery multiple times.
Weird, huh? I'm perplexed by this. I even tried using a wrist grounding strap.
I reloaded the FW again(about the 6th time) this morning and no issues in 45 minutes of playing.