RDRAM Pinout/Broken Trace repair?

[Link83]

Hi all,
I was just about to mod and N64 but whilst removing the heatsink I appear to have accidentally lifted one side of the first RDRAM chip off the board (The side that only has 4 pins) and I think the pads underneath are broken

However, the N64 still appears to boot, so i'm wondering how important these 4 pins actually are? What should they be connected to?

Also, does anybody have a datasheet for the RDRAM chips used in the N64? (I seem to remember seeing one a while ago)

Thanks in advance

[marshallh]

Those are grounding pins and though it may still work I'd recommend soldering those to the nearest ground plane. They don't do much else though.

[Link83]

Hi Thanks for your reply

I have to say though that im alittle confused. I just tested a PAL 'NUS-CPU(P)-01' board and the two RDRAM chips are Revision B and the 4 pins on both chips are all directly connected to 3.3V, not Ground?

The board with the broken pads/traces is an NTSC 'NUS-CPU-03' revision, and the RDRAM is Revision A, but on the RDRAM chip that is still connected to the board the 4 pins are not connected to anything as far as I can tell? (Tested Ground, 3.3V, 5V and 12V)

Are the four pads on the first chip (near RCP) directly connected to the 4 pins on the second RDRAM chip? (So breaking the connection for both chips) Any chance anybody with an NUS-CPU-03 board could double check if they are all connected, and if so, to what? (No offense intended marshallh)

[timmeh87]

According to my schematic, those should be power pins. just solder them back down where they came from? there's no way you ripped up all that copper, its completely surrounded by a large 3.3v trace.

The RAM datasheet says they are for 'support' or something. Just make sure the chip doesn't get ripped off any more.

[Alie]

According to the datasheet they are only mechanical support pins (they only keep the chip there )

[Link83]

Thanks for the replies

I meant to update this thread as a forum member here sent me a link to this RDRAM datasheet (Not necessarily the exact same brand of RDRAM used in the N64, but it does have the same pinout):-
http://www.datasheetcatalog.org/datashe ... 718C50.pdf" onclick="window.open(this.href);return false;
The bottom of page 4 does seem to confirm that they are just 'mechanical support pins'

Also found this picture in an old thread in these forums:-

Seems to show they are not connected to anything at all.

The strange thing is on PAL N64's these pins are connected to +3.3V, if you look carefully at a PAL motherboard you can see the +3.3V trace connecting to the pins. I dont know if this difference is because im comparing 'RDRAM18-NUS A' to RDRAM-NUS B', if its a PAL/NTSC difference, or if the motherboard design was simply improved in the year or so difference between the revisions.

Anyway, I soldered the pins back down that didnt have a ripped pad and the N64 still works fine, so please consider this sorted

Thanks for everyones help