Hi to all!! a pleasure to be in this forum.
Recently i purchased a broken GX4000 from ebay. The console has no video/sound output, i make some test on it:
-No video output from SCART
-Voltages are normal (stable 5v in z80, ram... 7805 ok)
-When power on with Burnin Rubber cartridge there is no sound output on headphones.
-The clock seems to be ok (i have 4 mhz clock in z80, acid...) perhaps the ASIC be ok? (see the picture)
Screenshot_2022-04-30_11-56-23.png
-The RAM seems ok, no excessive heat on it
-When power on with lab power supply at 11v, it draws 0.46amp (look to be normal)
-Seems to be pulling data from the eprom (see the capture with chinese logic analyzer and pulseview)
Screenshot_2022-04-30_11-24-53.png
I'm newbie with GX4000 and CPC. Any suggestion to continue with tests?
Thanks in advance. :)
Kind regards