have bcd436hd been turn off for a few months change battery's will not come on when plug in to power show no battery and will power up trying to get back up and running any one seen this before
Will it boot up & scan if using external power? If not, are you using the original cable that came with the scanner, or a different one. If not the original, then make sure that the cable you tried has the correct wiring both for data (ipdating the main database and any Favorites lists), as well as the wires needed for providing power to operate and/or charge the scanner's batteries. Some replacement cables that you find online only have the 'data' wiring, not the proper wiring for also providing power.
If the scanner has been sitting unused for a while, it's at least possible that one or more of the batteries are completely dead, and will not accept a charge in the scanner itself. If you have a 'smart', external, battery charger, see if it can revive & charge the batteries.
For that matter, you could simply put in a set of regular (alkaline) AA batteries & see if the scanner will start up. If it does start up with those, then the batteries that were in the scanner have an issue. (Of course, you do not try to charge non-rechargeable batteries.)