Nokia 8250 · NSM-3D · System module RM7LD
Explore the Nokia 8250 service schematics (Issue 3, 11/2000): rotate the board in 3D, zoom into every circuit sheet, and search components by reference (e.g. N100), part number, signal or function.
The board is split into an RF part and a baseband part (sheet A-D1). Baseband is made of five blocks (sheet A-D2). Click a block to see its components.
CCONT2M (N100) creates every regulated rail from the battery, runs the SIM interface, ADC measurements, sleep clock and power-up reset. CHAPS (N101) controls charging.
MAD2WD1 (D200) combines the ARM MCU, DSP and system logic. It runs the firmware from the Flash + SRAM chip LRS1341 (D210) and drives the keypad, LCD, RF synthesizer bus and data buses.
Dual-band GSM900 / GSM1800 radio. HAGAR_4 (N505) holds the receiver mixers, synthesizer and I/Q modulator. PF08103B PA (N702), SAW filters, diplexers, IN066 VCO (G800) and 26 MHz VCTCXO (G830) complete the chain.
COBBA_GJP v4.1 (N250) is the audio codec and RF interface: it amplifies the microphones, drives the earpiece, and converts the RX/TX I/Q signals between MAD2 (digital) and HAGAR (analog).
IrDA port. QSDL-M134 (N400) is the IR transceiver on the FBUS lines; TK11228AM (N401) is its 2.8 V regulator. IRONX switches the transceiver on.
Keypad matrix (ROW0–4 × COL0–3), power key S330, LCD module H300, LCD and keypad LEDs, buzzer B301 and vibra M300. TM23A (N310) drives LEDs, buzzer and vibra.
Receiving a call (RX)
Talking (TX)
Power-up sequence
Reference designators and values are transcribed from the Nokia PAMS service schematics (Issue 3, 11/2000) for educational use. Descriptions are explanatory — always check the original sheet in the Circuits tab before a repair.