Please HELP me with this X68000 PSU!

Started by deathx, December 04, 2008, 06:11:40 AM

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deathx

Hi buddy, i'm a new guy here, from italy.
I just got my sharp x68 Super HD from Yahoo japan auctions. Well... it was working fine, i was using a convertor (110-220 200watt).. but it was just blink for a second, then shut down. I figured out later that it was too low for it, but the machine after that is no longer working.

I found the repair guide... everything was plugged as the guide but when i turn on it, the power just remain RED and nothing else work. Do you think the Ic is not correct? i'm using a 74LS08 (instead of 74LS04), i was thinking it works maybe the same.. Could it be that?

Sorry for my english errors. Please help me, no one seems interested on this awesome machine!

NFG

Well the 7408 is definitely the wrong chip, it doesn't INVERT the signal which is why we need a 7404.  Now, it's early in the morning and I'm still kinda blurry, but I can't see any way to wire up a 7408 so that it inverts the output.  (7408 datasheet)

deathx

#2
Lawrence, i was realy counting on your answer  ;)
Soo, it's the chip. I was imaging that. I usualy do some mods but i've never used chips or resistence, so i'm a little bit confused.

In the guide you wrote, i see in the description "74HC04",but the picture say "74LS04". The pictured one is good right? As i'm going to buy that chip (i've tryed to find it on some mine broken arcade jamma Pcb, nothing comes), do i have to say something specific, or just give me a 74LS04? they are all inverted right? Thanks  ;)

Ps: What about using a 74LS05? http://www.datasheetcatalog.com/catalog/p89840.shtml Or a HD74LS04? http://www.datasheetcatalog.com/datasheets_pdf/H/D/7/4/HD74LS04.shtml
They are inverted too, and i already have them! could i?

deathx

Oh YEAHHHHHHHHHHH  :D
It works just awesome!! I'm soo damn happy about it! I finally putted that HD74LS04.. and just works PERFECT!
Lawrence, Thanks for your amazing repair guide. You save and Italian dude  ;)

Now i need a Keyboard  :D i can't change video solutions..
Fortunatrly i will be in japan for christmas.. i'll buy a mouse and a joypad too.

Thank you very mutch