Hi!
Furthermore to my previous tale of woe I managed to read the 5-digit code out of the eeprom (I read back 81175!), but on reassembling and testing the thing it was dead with the LCD totally blankety-blank!!!
When it's powered up I get the red alarm/safe LED flashing on it's front panel and it goes off if you press in the LH control knob, and if I turn on the vehicle lights the LCD lights up (but still blank!!!) - but there's not a sound out of it, not even a pop, click or hiss!!!
The CD changer'll take in a CD suggesting the main power supply is reaching the internal bits but I'm none the wiser without a schematic!!!
I've had a look at some Becker schematics - their BE3300 has an identical front-panel button/knob layout but it's a cassette unit so that's no good!
Did Alpine make the AL/MF2910 specially for Mercedes or is it one of their own standard products recanned to make sure you can't find a circuit for it?!
There are two processors, one 51T25597Y02 (IC503) and one MB90F594Y35 (IC502) on the main PCB with a 24C04 EEPROM (IC501) - the rear sticky-up o/p bpoard has the reference 84D01455K01 and it has the following plug connections (connector CH802) annotated on it:-
Pin 1 ACC, Pin 2 P-CONT1,Pin 3 P-CONT2, Pin 4 SWD +B, Pin 5 T-MUTE, Pin 6 WAKE UP, Pin 7 A-MUTE, Pin 8 AMP STBY, Pin 9 A GND, Pin 10
A-GND, Pin 11 BOSE, Pin 12 R-L, Pin 13 F-L, Pin 14 S.G. Pin 15 F-R, Pin 16 R-R
If anyone can suggest anything I can try next it'd be a great help as I've had my eye operated on very recently & seeing silkscreen and chip nos on PCBs etc., is really difficult now!
Chris Williams