Audio Systems: Radio problem, automatic car wash, loud thump

Question
I have a 2004 Toyota Corolla with 9500 miles on it. Last year, about two months after buying the car when I was two hours into my drive with the radio on FM, it suddenly made a loud thump while the display panel of the radio which shows the station you are currently on blinked off and then on again. This happened continuously every 5 seconds or so.  Turning off the radio and turning it back on did nothing, nor did changing the station. I turned the radio off for the rest of the trip. On my next drive, the radio was ok.

The only thing I could think of was that I had recently gone through an automatic car wash and wax, and that some of the wax may have damaged the antennae mounted at the hood of the car.

Well the problem seemed to go away until just last week when I was about 10 minutes into my drive.  The same thing happened, the loud thump and the display panel blinking off and then on.  Again, the thump and display flash would happen every 5 seconds or so.  Driving in the last few days I've had no problems with the radio.

Can you give me any advice into the seriousness of this?  Do I just need a new antennae or do I need serious electrical work done to fix this? Thanks for any help!

Answer
Julia,
The antenna wouldn't cause the display to blink on and off! The thump in the speakers and the blinking display tells me that some kind of a DC power feed to the stereo is failing or perhaps a voltage regulator may be failing inside the stereo. I have seen blinking displays on other makes/models of stereos and it is caused by a data communication problem between the various circuits on the main boards. You may want to have your stereo checked out to see if defective connections may be causing the problem.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net