AMI TECH TIP


TECH TIP NO.           29.001

DATE:                  August 17, 1991
BOARD TYPE:            Series 29, SX Cache II
BOARD REVISION:        B
BOARD FREQUENCY:       20 MHz and 25 MHz
ORIGINATOR:            Terry Brown
RELEASED BY:           Documentation Control

Several cases of non-functional on-board floppy disk controllers on Series 29 
boards, both 20 MHz and 25 MHz, have been reported.

ICT testing of several of the failed boards has shown that capacitors C29 and
C30 were exchanged in position on the board.  This causes the oscillator 
circuit for the on-board floppy controller to fail to operate, resulting in 
failure of the on-board controller.

The proper values for C29 and C30 are

                          C29 - 20 picofarads
                          C30 - 10 nanfarads.

This error is detected by the current ICT program for this board.