Dreamcast BIOS chips (MX29LV160TMC-90)

Ok.
I always try to leave the original chip intact.
I heat the legs up and lift them with an x-acto knife.

Now I'm a little bit confused...in the rom datasheet Pin 10 is A1 and Pin 21 is Q3, but in this guys schematics its Pin 10 is A2 and Pin 21 is D3 (Q3 and D3 are equal i guess cause both datalines) ?....
http://yam.20to4.net/dreamcast/va1.html

 

Address lines don't need to match up. A1 on one chip might connection t to a different address line on the other. It's honestly trivial to do with a multimeter.

 

fuck me, I have a multimeter but not with continuity testing...must do this with ohm readings...

 

I only use resistance anyway. Just need 0 ohms and it's directly connected

 

I'm freakin the fuck out over this mod!

Managed to rewire the Pin 10 and 21, DC boots up.
I put a disc in and its stuck on the "reading" screen...

Another thing I tried, was swapping the original bios chip with the region free and then piggyback another region free chip to flash dreamshell to it, selecting with a switch on Pin 12 which chip is enabled. I only get black screen everytime. What the heck is wrong with thing fuckin DC? I wired everything correct.

 

Picture of your work.

pin 12 needs to be connected with resistors, as when you enable one you need to disable the other (no, having nothing connected to it is not disabled)

 

Please I need your help. The trace from Pin10 is now lost. To which Pin does this connect on IC502?
Yeah I got everything soldered like in the tutorial from mmmonkey, 10k resistors and a switch.

 

Pictures

 

Desoldered the piggyback chip and piggybacked it to my own DC with regionfree chip, works.
Installed Dreamshell as bios on one chip, black screen at bootup...anything needed for this like connected SD-Card?

Here is the other DC with lost trace to Pin 10 IC 501.
http://farm6.staticflickr.com/5483/11272901676_b28f3657a1_o.jpg
keep in mind, under the IC501 the trace is also cutted, so I would like to have a good solderspot to reconnect directly to the ICs.

 

Which file are you flashing for dreamshell? As there are about 5

 

I burned DS 4.0 and hit directly to install DS from the desktop symbol...
Think its RC1 Beta 4...
I put DS folder on SD card, then DS starts up, but isn't there a way without the folder on SD card?
so which one do I need?

 

No, dreamshell is too big for the bios. The bios it flashes is just a loader that checks for sd card and then boots off that

 

Ok then it functions like it should.
But can you please help me out with the other DC and its broken trace, alternative solderpoint on IC502 from IC501 Pin 10 A1 ?

 

Just set your multimeter to resistance and check your other console? It will take you 5 minutes, why try to make some else do it for you when you have all you need to do it yourself?

 

The DC with installed regionfree bios and piggyback Dreamshell and SD-card slot is running.
The only problem I have with it, when I want to rip a gd to sd it says "GD reinit failed".
What does that mean?

The DC with broken trace...I can't manage to meassure anything because the traces are too tiny.
I asked you not to do it for me, I thought you might have schematics for IC501 and IC502 how they are connected.
Sorry but my multimeter meassure needles are not tiny enough to meassure it
And I really want it get running again -.-

 

You can use the working DC to find out which pin connects both ic501 and 502. You are making it sound much harder than it is

 

The other DC is for a customer and already finished and closed.
I send him this tomorrow, thats why I dont meassure it there.

 

I'd like buy to chip what i can do ??

 

Go here:
http://www.assemblergames.com/forums/showthread.php?39971-For-Sale-Modding-parts-chips-etc

 

I think i'll lift the IC502 today, got no other chance of getting to meassure the trace back to its point.
Has anyone done a lift of IC502 and IC501 and then took a picture of the traces yet?
Might be helpful for the future i think...