PlayStation Development Network

Hi fellas.
How are you?

I've an SCPH-1000 (serial 6323386 - CPU 14th week of '95) with an strange problem (I've repaired a lot of PS -- but this one is tough).

Laser replaced (KSM-440AAM --> KSM-440BAM), excellent RF signal (no jitter, stable RF envelope and 1.2v p-p), very fast reading, but when the console starts reading the SCEX, it stuck on double speed.

SUB-CPU recognized if the disc is original or not, CD-DSP it's working with a CD audio, BA looks fine...
Maybe a bad CD-XA encoder?

Here's a video:
[youtube][/youtube]

...And a pic of the RF signal:

Thank you and have a nice day!

P.S The unit is not modchipped!


UPDATE:
replaced the CD-XA encoder (CXD1189 --> CXD1815), CD-DSP, SUBCPU, RF AMP... same problem.

It could be that the main cpu when issuing CD Commands is stuck waiting for a response that never comes. Getting stuck on that white screen could happen in that case. Maybe the CD-ROM Controller is bad or has a bad connection/cold solder joint?

Hello, thank you for the response.
I've replaced all the CD servo's IC. Nothing changed...

As you said, the CPU is bad. Because, if you force an STR playback, there a lot of square artifacts (bad MDEC decompression module).

So... for me, it's unrepairable.

SCPH-1000 have a different CPU from a 1001 or 1002. This makes me sooooo sad !

Here's a pic of the artifacts:

I had the same issue and turned out it wouldn't work with one of my controllers so I switched controllers and reset and it was fine. Probably not the same thing but
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Hi guys... just a little update.

I've replaced the CPU with a compatible one (picked from an old SCPH-1002 - 208pin) and... NOTHING.

ALWAYS STUCK.

I really don't know what a kind of problem have this PlayStation... but, I don't get it T-T

Maybe the holy Trimesh can help me

GUYS... PROBLEM SOLVED!

IT WAS THE BIOS!

I replaced the BIOS with another from an SCPH-1002 and it works (SCPH-1000 use a 40 pin BIOS package). Probably it remains stucked because the code was incompleted or faulty during the SCEX check.

It's working flawlessy!

Congratz !

Squaresoft74 wrote: ↑September 5th, 2022, 4:47 am Congratz !

Thank you, mate !!!
You know a method to dump the BIOS chip with a programmer?

If you have a serial cable, you can easily dump it from the console itself using Unirom/nops and this command for example:

I think he means he wants to dump the chip he pulled that was failing to boot the console, probably so he can verify that the BIOS chip is bad.

Oops sorry, i didn't get it right and don't know then.

MottZilla wrote: ↑September 9th, 2022, 3:17 pm I think he means he wants to dump the chip he pulled that was failing to boot the console, probably so he can verify that the BIOS chip is bad.

Yeah, my idea was to dump this bios and a make a comparison from a good one. I've an XGECU eeprom programmer, but I can't find a guide how to dump it :/

~PSXLoVeR95~ wrote: ↑September 9th, 2022, 9:44 pm

MottZilla wrote: ↑September 9th, 2022, 3:17 pm I think he means he wants to dump the chip he pulled that was failing to boot the console, probably so he can verify that the BIOS chip is bad.

Yeah, my idea was to dump this bios and a make a comparison from a good one. I've an XGECU eeprom programmer, but I can't find a guide how to dump it :/

I had no idea that one can see the week that the CPU is manufactured, that is wonderful!

I am working on compiling a list of what is inside each console going off of SN, i.e. BIOS v1.0, CDROM BIOS VC0A, SNXXXXXXX, SCPH-1000.

This is important because the CD Player Swap Trick (the only swap trick where you replace the real PS1 game disc when it is stopped with a backup CD-R) requires VC1A, VC0B, or VC0A CDROM BIOS versions.

Can you confirm that the CDROM BIOS is VC0B? All you need to do is run https://alex-free.github.io/tonyhax-international . You should still be able to use the CD Player Swap Trick even though you changed the BIOS version. You can use that to boot the Boot CD image, and it will tell us what the CDROM BIOS version is.

If you are up to it, I would love to know what the original BIOS version is of this console. Is it v1.0 (I think all 1000s are) or is tt v1.1?