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SCPH-1002 BIOS corrupt.

Posted: November 7th, 2015, 12:35 pm
by McMiller
Heya, sorry if this is in the wrong place. I'm not too sure where to put this query.
I have a SCPH-1002 which functions fine as a CD player, but does not load games. I suspect the BIOS is at fault.
Image
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Is there a way to restore full functionality to this PS1?

Re: SCPH-1002 BIOS corrupt.

Posted: November 7th, 2015, 2:07 pm
by Shadow
Could be the DRAM or GPU. As a test, press down on certain IC's whilst the console is booting. It might cause it to flicker, and that way, you can pin point exactly where is going wrong. I myself have had a PU-8 with a poor soldered DRAM bank from Sony, so check those first.

Just be careful when you have your PSX open.
One false move and you will get a very nasty shock from the power supply.

As a tip, put some cardboard over the top of the PSU just in case your hand slips, or your elbow touches it.
Better safe than sorry.

Re: SCPH-1002 BIOS corrupt.

Posted: November 7th, 2015, 9:38 pm
by cybdyn
laser head is bad- it's a cause of problems. it's not BIOS)))

Re: SCPH-1002 BIOS corrupt.

Posted: November 8th, 2015, 8:57 am
by nocash
bad laser on a psx that can play audio discs and load the boot executable?

Re: SCPH-1002 BIOS corrupt.

Posted: November 9th, 2015, 5:12 am
by McMiller
I swapped the lens with a known working unit and it still fails to boot. I can rule out faulty lens then. I'll check out the mentioned ICs on the board.

Re: SCPH-1002 BIOS corrupt.

Posted: November 9th, 2015, 2:54 pm
by Shadow
McMiller wrote:I swapped the lens with a known working unit and it still fails to boot. I can rule out faulty lens then. I'll check out the mentioned ICs on the board.
There's nothing wrong with the laser deck or laser circuitry...
Yes, check those IC's I mentioned. If you can't pinpoint the problem, I'll tell you some other areas to check.

Re: SCPH-1002 BIOS corrupt.

Posted: November 16th, 2015, 8:20 am
by McMiller
I had a feeling the laser assembly was fine, but i'm a sucker for potentially quick & lazy solutions.
Had some free time to take a look at the IC's and found no issues. Took macro pictures of the solder points to see if there were any poor joins but everything is soldered a-ok. Regardless I have a hunch that the DRAM is the one at fault here.

The pic's I posted above are from Colony Wars where it reaches the piracy screen, but every other game won't even get that far.

Re: SCPH-1002 BIOS corrupt.

Posted: November 17th, 2015, 8:45 pm
by cybdyn
bad laser on a psx that can play audio discs and load the boot executable?
Yeah, it's not 100% dead, and the problem maybe in lens, motor, or something else in mechanics, like it load data from center of the disc, but when heal go to out corner of the disc it fails.. especially it relate to FMV freezing, sipping frames,
anyway result is same, it works w/ CDDA disc well , cause of it need only 1x speed)) but, it fails to load games...

but sometimes, i saw problem w/ Memory on 1002, rusty throu-holes or memory ic and mother board.