Laptop works with adapter but wont charge new battery.

Thanks for your replies. It is always encouraging to find others who want to help.
Yes, the laptop works great with either the adapter plugged in or with a charged battery. I also suspected the laptop charging circuitry.
I have read reports that suggested Dell may have logic which can turn off battery charging if certain battery characteristics are detected. I wanted to eliminate this possibility before opening up the laptop. Laptops are so tedious to work with.
Oldernrocks

The AC adapter powers up and operates the computer very well. Even with the laptop shut off and the adapter plugged in it will not charge the battery.
The charging circuit is not working in the laptop. There appear to be two options; (1) there an electrical problem in the charging circuit that prevents it from charging the battery, or (2) there is something in the software controlling the charging circuit that is preventing charging. If we assume the software is preventing charging it could be because the software is corrupted or because it was designed to discriminate between batteries and it does not like the battery connected.
I have tried two different batteries, both of which will charge up to full capacity with an external charger, as indicated by the laptop battery test, and each will operate the laptop until they run down.
I ran across an identical problem reported by another forum member, nonoitall "Yet another "new battery won't charge" question (Dell Inspiron 4150)"
http/www.tomshardware.com/forum/59976-35-battery-charge-question-dell-inspiron-4150
He found a solder joint that he was able to repair and correct his charging problem.
I think I am going to dig into the laptop.
Oldernrocks

Thanks to Veteran++ for his input.

I haven't had the time to dig into the laptop yet but I will check coil FL1 as suggested by nonoitall.
Oldernrocks

I took the laptop apart and found no obvious faults with connectors, solder joints, or discolored components. I adjusted the BIOS to display all diagnostic messages on start-up and, for the first time, saw a Dell message which in effect said the adapter being use did not have sufficient capacity to charge the battery and that a genuine Dell adapter was required. I bought a used Dell adapter on eBay and now the battery charges as it should. This sounds to me like a ploy by Dell to sell their own over-priced components. I fail to see why the battery could not be recharged, especially at a very low rate, without creating any problems for the computer.

The reaffirms my conviction that nearly everyone should build his own computer for better performance, longer warranties, more flexibility, improved expansion capability, and no intrusive bloatware.