i have tough 1 regarding imac g5 als 17" 2mhz fixing. first want point out familiar innards of these ancient beasts have fixed couple 1st gen imac g5 isights , duos.
when plug in cord in psu, 1st diagnostic led comes on when trying start computer second diagnostic led comes briefly on , goes off. nothing else happens, no chimes, nothing. according apple kb sign of faulty psu. yet, have tried replacing psu , same result.
weird part if unhook lcd cable computer starts (it chimes) display off. puzzling start inverter hooked lcd display cable off not start inverter entirely taken off lcd cable on. seems lcd prevent computer starting. thought inverter draw current not lcd it's else.
had similar happen them? inverter faly draws when lcd hooked? kind of short in lcd or make draw inverter unhooked?
thoughts, comments, ideas welcome.
in advance
g.d.
hello.
have 1 of these great digital photo frames (imac g5)
had psu troubles.
darn, threw out spare g5 inverter board.
anyway, here's how things appeared function:
psu provides power , power signals mainboard similar standard computer. provides 24v inverter iirc. inverter provides power fluorescent backlights, 500v.
unplugging inverter might either set off kind of fault detection or causing marginal psu malfunction.
lcd has 2 kinds of connections: lcd cable carries data , power actual lcd, , high-voltage wiring backlights.
if unplugging low voltage data cable, there either: 1- fault in display or 2- either psu or mainboard can no longer supply power it. cause described below.
if unplugging high-voltage wiring backlights, failed backlight bulb indicated.
g5 imacs ran hot. especially, tiny psu ran hot. common problem failed or "blown" capacitors on mainboard or in psu.
capacitors on mainboard easy check- tops should flat no sign of leakage. there 20 or tend fail on board , when top tends bulge outward or burst.
psu has failure-prone capacitors inside. (that's wrong g5) have disassemble @ caps. bulged ones bad , causing problems. clean ones ok not necessarily.
picture shows several bad caps. ones on far right , left ok, bulged ones in middle bad.
luck,
keri
ps. many g5 imacs plagued faulty capacitors nichicon, reputable company made mistakes.
also, electrolytic capacitors sensitive heat , g5 imacs ran hot. tiny psu doesn't have fan, relying upon convection , system airflow other fans.
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