[Hardware Mod] 8MB in (PU-18) Retail PSX

[szalay_1]

i used the cd image on xstation from the package tunertom post.

Where i can get that cd image file ?

[Jackhead]

I have attached the fixed 8MB Ramtest package zip to this post, just incase anyone else has been searching for it as long as I have!


Fixed 8MB RamTest set.zip

Its include here, look some posts above.

[corro23]

Sorry if this has been covered somewhere already. Has anyone tried to piggyback RAM from a second PSX? I know people have done this (piggyback RAM) with the OG xbox 1.6.

[szalay_1]

Sorry if this has been covered somewhere already. Has anyone tried to piggyback RAM from a second PSX? I know people have done this (piggyback RAM) with the OG xbox 1.6.

What does mean "piggyback" ?
Could you elaborate?

[corro23]

What does mean "piggyback" ?
Could you elaborate?

Sure ... Placing the original RAM from PSX A directly on top of the RAM on PSX B and soldering it in.
I dont know anything at all about how the hardware works at this level. Maybe this is an apples to oranges question, but thought it was worth asking.

EDIT: Guess if this worked it would only expand it to 4MB.

Here is a link to a video of it being done on the original xbox 1.6
https://www.youtube.com/watch?v=esM_-4GTU9E

[szalay_1]

What does mean "piggyback" ?
Could you elaborate?

Sure ... Placing the original RAM from PSX A directly on top of the RAM on PSX B and soldering it in.
I dont know anything at all about how the hardware works at this level. Maybe this is an apples to oranges question, but thought it was worth asking.

EDIT: Guess if this worked it would only expand it to 4MB.

Here is a link to a video of it being done on the original xbox 1.6
https://www.youtube.com/watch?v=esM_-4GTU9E

Now already understand the term "piggyback".
Good idea for psx, but i'm not sure if it would work..
(for more xbox classic i also did ram upgrades, but for v1.0-v1.5 between )

[MasterLink]

You'd still need a way to address each chip individually, just remember that. You're not straight piggybacking it, or both chips would merely mirror each other.

[corro23]

You'd still need a way to address each chip individually, just remember that. You're not straight piggybacking it, or both chips would merely mirror each other.

I see. Thanks. So, basically the PSX would see it as duplicated ram and not expanded ram. It sounds like anything put in a memory address would also be placed in the duplicate address on the piggybacked chip.
To address each chip individually you would probably need a custom bios?

[MasterLink]

You'd still need a way to address each chip individually, just remember that. You're not straight piggybacking it, or both chips would merely mirror each other.

I see. Thanks. So, basically the PSX would see it as duplicated ram and not expanded ram. It sounds like anything put in a memory address would also be placed in the duplicate address on the piggybacked chip.
To address each chip individually you would probably need a custom bios?

No, you'd need a way to address each chip individually still. The BIOS will accept 8MB just fine. This involves pin-lifting (like chip select for example) to solder it elsewhere so the CPU can address it individually without both piggy backed chips saying (here!!), so it's not straight piggy backed or the system will see both chips as one singular chip.