November 13, 2019, 06:46:10 pm

Daydream ROM box kit

Started by pentium, September 15, 2008, 11:26:02 pm

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pentium

I have in my posession a complete Daydream kit.
Now it is in my interest (as well as a few others) to try and make a schematic so we can make more.
The problem is that to do this I would risk ruining the unit by desoldering the whole board so we can see every trace and possibly damaging a component or the whole board (I'm looking through the board with a light and I'm not seeing any middle layers so there is only the top and bottom) and even if we could produce a new trace layout, two small chips have had their numbers ground off with a third partially readable.
I need help with IDing the three chips and I can do the PCB scanning.
Can we do this?

-NeXT 68040 Cube with NS 3.3 and 64Mb ram

cubist

Quote from: "pentium"I need help with IDing the three chips and I can do the PCB scanning.
Can we do this?

Maybe...  The usual way to do this is destructive.  Open the packages and 'scope the dies.  They really ground off the markings?  Suggests somewhat standard parts or an attempt to avoid licensing problems.  Maybe someone has one without the grinding.

And check the board again.  Is it really only two layers?  That's easy to deal with and it might provide additional info to identify the chips in question.

pentium

It only looked like two layers.

-NeXT 68040 Cube with NS 3.3 and 64Mb ram

stevebez

often circut boards will have the id of the chip silkscreened to the board under the chip.

pentium

Well I guess it's possible here.

-NeXT 68040 Cube with NS 3.3 and 64Mb ram

cubist

How about some front and back photos of the board?  If you have a scanner, it should do nicely as a camera/macro lens combination.

pentium

Do you want the ROM chips on the board or no? Aside from those other chips whose markings have been ground off, you can't really see any other traces. That's why I want to completely disassemble the thing: So I can see every trace.

-NeXT 68040 Cube with NS 3.3 and 64Mb ram

cubist

If they're socketed, pull them.  Might get some extra info under the sockets if they're open-frame.  But stay away from the desoldering station for now...

pentium

Okay, I'll get on it.
In the mean time, it might be nice if korneluk was able to pull his ROM chips and see if the chips on his board were ground as well.

-NeXT 68040 Cube with NS 3.3 and 64Mb ram

pentium

Well I couldn't use the scanner (the components on the board were causing the lid to not close properly and this the images were coming out blurry) so I used the next best thing which was a good source of light and my Olympus C-2100UZ.




-NeXT 68040 Cube with NS 3.3 and 64Mb ram

cubist

... yep, two layer.  A GAL whose programming will have to be extracted.  My thought on the defaced chips was that these were something they pulled out of a Mac from that era.  To make it just enough work to be too expensive to sue them.  Don't know if that's the case, just my natural inclination...

pentium

A GAL?
Oh great, I have nothing on hand to read that let alone your regular run of the mill EEPROM.

-NeXT 68040 Cube with NS 3.3 and 64Mb ram

cubist

I've started a hand-drawn schematic which I'll email to you to get you started (PM me with your email address).  Admins, it would be nice to have a place to put files...

pentium

Well the schematics are advancing slowly but we still have no idea about those chips.

-NeXT 68040 Cube with NS 3.3 and 64Mb ram

rice0067

One thing that someone at my work suggested is too look up the patent for this board. They might not directly ID the chips but the circuit, and what those chips do will be.
-bill