About this replacement
Philips Pronto Pro 900 / TSU7000/37 — 4.8V Ni-MH Replacement Battery (255789)
This is a 4.8V, 750mAh Ni-MH replacement battery for the Philips Pronto Pro 900 and TSU7000/37 universal remote controls. It matches the OEM part number 255789 and drops into the original battery bay with no modification. The Pronto Pro 900 uses this battery to power its touchscreen display, IR transmitter, and onboard programming memory.
- Pronto Pro 900 and TSU7000/37 compatibility: Both remotes share the same 4.8V battery bay, connector orientation, and cell arrangement. One battery replacement covers either unit without any adapter or wiring change.
- Bench tested on actual hardware: We ran this battery through full charge and discharge cycles on the Pronto Pro 900. The cell pack held voltage across the IR firing sequence and sustained the touchscreen backlight without dropout.
- Ni-MH cell replacement tip: The Pronto Pro 900 uses a 4-cell Ni-MH pack. If only one cell is weak, the pack voltage drops enough to cut IR output even though the display still lights up. Replace the full pack — not individual cells — to restore consistent signal throw.
Why the Pronto Pro 900 loses IR range before the battery appears dead
Ni-MH cells drop voltage gradually rather than sharply. The Pronto Pro 900's display draws far less current than the IR LED burst during a command transmission. This means the screen stays on and the remote feels functional, but the IR LED no longer has enough voltage to fire at full intensity. At around 4.0V under load, the effective range drops noticeably. Replacing the battery pack at that point, rather than waiting for a complete shutdown, prevents missed commands and re-training sessions.
Pronto Pro 900 showing full charge but IR stops mid-session
This happens when individual cells within the 4-cell pack age unevenly. One weak cell pulls the pack voltage down during the high-current burst of an IR transmission, even though the pack reads adequate voltage at rest. The Pronto Pro's charge indicator measures resting voltage, so it can display full while the pack fails under load. Test by pressing a command button — if the remote works from 30cm but not 2 metres, the pack voltage is sagging below 4.2V under load and the battery needs replacement.