Why so many different GND points?

[witchy2k1]

Can anyone tell me why there are so many different Grounding points used on the various different models?, why don't all diagrams just use the large copper border that runs around the entire board?

Do these specific grounding points on diagrams have any particular purpose?

[eljuapo]

Originally posted by witchy2k1
Can anyone tell me why there are so many different Grounding points used on the various different models?, why don't all diagrams just use the large copper border that runs around the entire board?

Do these specific grounding points on diagrams have any particular purpose?

I don't know about the PS2 circuitry as such, but I bet that the specified GND points found in the installation diagrams are connected to the GND of the power supply.

[charlie_ps2]

A bit of a silly question. Why should it matter? the copper border is supposed to mate with the metal case. So you don't want really to be soldering everything to that.

[witchy2k1]

LOL

I know it's a bit of a silly question, but....the reason I'm asking is....

I decided to ignore the normal GND point on the Magic 3 V7 installation diagram, I opted for the large copper border instead as this was closer to the location of the GND point on the chip.

When I did this the chip was dead, nothing booted, I then removed this grounding point and used the 'normal' ground point and the chip worked fine. Now this is confusing me, ground is ground is it not? all grounds points are equal, so why would the earth point I chose (which was only about 5mm away from the ground point on the chip) not work??

Does the PS2 have 2 independant ground circuits?

[Relayer]

No, using two independant ground points could create ground loops, which are not desireable in digital equipment. For the love of God, I can't remember why, as I studied this more than twenty years ago, but I think it has to do with creating unwanted oscillations which are counter-productive.
I'd say your original ground connection wasn't sound, as using the outer edge should work ok.
Regards,
Relayer

[charlie_ps2]

Bless Relayer - he should be asleep at this hour!

The copper edge has to be seriously scraped to get an earth. it is covered in lacquer as with threst of the motherboard. All GND points on the PS2 including the edge are bonded so there will be no ground loop.

[Relayer]

Sorry I wasn't more specific.
I was meaning that the power supply has two seperate gounds that are isolated form each other.
I guess I do need some sleep, as its 2:30 in the morning...lol
I'll finish my smoke, then I'll take my old bones to bed.
Regards,
Relayer

[witchy2k1]

Originally posted by charlie_ps2
The copper edge has to be seriously scraped to get an earth.

All lacquer was completely removed from the patch with a scalpel knife, sanded a little then rubbed over with a flux pen, so I'm sure there was a good connection.

Although the chip is now working (sort of) I can't get PSX backups or PSX originals to boot - I'm getting either the "Disc Read Error" or Red "Insert Playstation2 Media" screens.

DVD-R are 'mostly working' and I'm getting that horrible fast clicking sound, I think u once described it as a something stuck in the spokes of a bicycle wheel!, lol

PS2 CDR are booting 100%
PS2 DVDR are booting 60%
PSX Originals 0%
PSX Backups 0%
DVD Movies 100%

I managed to get PS2 DVDR to work (60%) by using alternative W point.

[witchy2k1]

I can get PSX originals to boot if I remove the SCEX wire and some of the laser noise has gone, although it is still there.

[witchy2k1]

Sorted it thanks to Charlies guide. :-)

Removed wire from SCEX, scraped surface mount and added lots
of flux, resoldered SCEX point - everything working 100%

A big thank you once again to Charlie_PS2 :-D