Will an N64 recognize an internal expansion mod w/ a jumper?

[stuntpenguin007]

When I solder 8mb of ram directly onto the n64 motherboard, will it recognize all 8mb when a normal jumper pack is inserted?

[snowpenguin]

Yes. This is how bentomo did his expansion pak on his starlight 64.

[stuntpenguin007]

ok Thanks.

[stuntpenguin007]

A few threads back, I basically asked if I should try piggyback 1 4mb ram chip onto one of the 2mb chips, and I was basically told not to.

Well... I did it anyways

To my surprise, It booted up on the first try. But it didn't recognize the extra ram. Is there a chip select pin I should be aware of? Datasheet anyone?

I'll be going through and testing continuity on all the pins, but it doesn't look like it has any shorts.

[marshallh]

You need to rewire a couple pins for this to work.

Pin 20 of each RDRAM is SIN (serial in), pin 22 is SOUT (serial out).

The serial out of each RAM goes to the serial in of the next one, in a chain-link arrangement. From what I can see, all the other pins can be wired in parallel. So you'll need to run a few wires to correct this, maybe cut a trace between the 2MB chips. It's up to you. Although it should work beware the rams will get very hot and you won't be able to cool the bottom one.

[mako321]

with enough thermal paste, you can do anything can you post a diagram of doing this kind of thing? it has caught my interest...

[stuntpenguin007]

I figured I'd have to take off the whole ram chip to pull up the two necessary pins, so I decided not to piggyback the ram. I'm now up to 6mb on the motherboard, but nothing happens when I power it on. Will it not work until I get 8mb of ram?

edit: I'll just remove the remaining 2mb chip and see if it works.

edit again: Tried removing the 2mb of ram. Didn't work. Checked 4mb ram connections. Didn't work. Well... I've got myself a new piece of junk

[timmeh87]

I dont think you understand what marshall was saying, because it definitely wont work without the second ram chip.

[stuntpenguin007]

What? I know the serial out of one chip has to go to the serial in of the next chip, but why shouldn't just one work if its 4mb?

I'll try add the second anyways.

edit: I tried adding the 2nd ram chip and... nothing. It looks like a clean install on both chips, but I'll be testing it with a multimeter anyways. Nothing happens when I turn it on, and the screen flickers a little when I turn it off.

[timmeh87]

The last serial out line has to be properly terminated, which is one of the functions of the jumper pack. If a chip is missing the next chip up will have a floating SOUT pin

[marshallh]

Just ground the last SOUT. In early protos it was even left floating. Don't know if that will work though.

[timmeh87]

At this point its quite possible that there's a solder bridge you cant see or something like that.