@Carlos Porto Carlos, meu caro, sua dica de olhar o datasheet do CI do charger valeu muito à pena cara... encontrei um trecho lá que dizia:
"When the ACDET pin voltage is higher than 3.15V, it is considered as adapter over voltage. ACOK will be pulled
low, and charge will be disabled. ACFET will be turned off to disconnect the high voltage adapter to system
during ACOVP. BATFET will be turned on if turns on conditions are valid. See the System Power Selection
section for details.
When ACDET pin voltage falls below 3.15V and above 2.4V, it is considered as adapter voltage returns back to
normal voltage. ACOK will be pulled high by external pull up resistor. BATFET will be turned off and ACFET and
RBFET will be turned on to power the system from adapter. The charge can be resumed if enable charge
conditions are valid. See the Enable and Disable Charging section for details."
Então baixei pra 17v na fonte de bancada que eu sempre testava entre 19,5v e 19v... e as tensões primárias todas nasceram, os LEDs estão acesos... agora vou prosseguir.....