Проблема решена. Был неконтакт в разъёме матрицы.
Beep Code Overview
Beeps Description Possible Cause
1 BIOS ROM checksum in progress or failure System board failure, covers BIOS corruption or ROM errors.
2 No Memory (RAM) detected Memory or Memory slot failure
3
chipset Error (North and South bridge error, DMA/IMR/Timer error)
Time-Of-Day Clock test failure
Gate A20 failure
Super I/O chip failure
Keyboard controller test failure
System board failure
4 Memory read / write failure Memory failure
5 Real Time Clock (RTC) power fail CMOS battery failure
6 Video BIOS test failure Video subsystem failure
7 CPU Cache test failure Processor failure
8 LCD LCD failure
(взято с
http://vlab.pp.ru/viewtopic.php?f=41&t= ... 971#p48971)