|
Title: Phoenix bootleg repair log Post by: Zabanitu on February 22, 2012, 06:14:03 PM this board is a bootleg wich comes with no solder resist at all: just plain semi yellow pcb with tinned copper traces.
on power up no sync and no cpu clock: replaced LS04 @ 7, LS74 @ 4 on gfx board. followed the sync circuit i found a dodgy LS138 @ 8 on cpu board. the board was missing a LS83 @ 9 on gfx board, couldn't find any so i built a daughter card with his brother LS283 (they only differ in pinout) board will come up but randomly the sync disappears again: found a nearly shorted to vcc pin 1 of a LS08 @ 16 on cpu board wich took output 14 of a LS161 (on gfx card) down thus disabling sync. board has been tested and some 2114 ram chips were replaced due to graphical glitches. the TDA1010 pow er amp is dead and the MN6221 melody ic is missing -> must find a spare or build myself a daughter card with another power amp and melody ic. !!! Zab. |