Good day all.

I acquired second hand promark 500 receivers (2) and both worked well until one as dropped and damaged the LED screen. Although the screen got damaged it still worked well when you use it with data logger.  I bought another set from Ebay and the  used all of the receivers until their memory got full. In deleting the data i might have deleted some supporting software from one receiver because after the deleting process, one receiver does not completely boot. It stops at the first screen with magellan until the battery runs down.

Because i had extra receivers, i packed this receiver but recently two other receivers are also faulty.

One is not recognized by my computer and does not allow recording onto an eternal memory.

The other one does not show the satelites and so no data is logged.

I tried reinstalling firmware but have not been successful.

Can anyone help me resolve these?