I had a somebody upgrade the software from ver 6 to ver 8. It seemed to work OK I decided to plug it in to my car cigarette lighter & use it on the trip back to the friend of mine that I had it upgraded for.
When I plugged it in only the green light came on but the screen did not light up. I tried many things but could not get to work.I think the problem may have been caused by power surge when engine started,causing a "spike" which locked the processor.when I got home & it was still not working I decided to open the unit. I could find no reset switches or links. I decided to try disconnecting the battery which is similar to resetting the cmos on a computer.this worked & the unit now seems to be ok data & settings were not lost but as I had just had a software upgrade decided to do a factory reset.
WARNING This is NOT something that a person without electronics skills should even THINK about attempting. I am an electronics design engineer. It is extremely easy to damage a component which would render the unit beyond repair.
You will need a T5x65mm screwdriver & a pair of small long nosed pliers. Remove the 4 screws that are located under the ends of the black rubber strips on the rear of the unit. place face down & lift off rear cover.
remove the 6 screws holding the mother board & daughter board antenna unit to the chassis,in one piece.The antenna cannot be separated from the board without destroying it.carefully lift mother board away from chassis disturbing the spring to the right & under lying ribbon cables connecting the display as little as possible.the battery lead connects to white plug with red yellow & black wires. gently unplug it from the socket (like fan socket on computer board) do not pull by wires,use pliers to free. leave disconnected for 5 Min.
reconnect & resemble in reverse order. do not press power on button until the 6 mother board screws are replaced.AGAIN DO NOT TRY unless you KNOW what you are doing.good luck!
ron, July 2009
