Saturn region-free BIOS: clarification needed

Hey guys, a couple of weeks (or months?) ago I bought a region-free BIOS from BadAd. He linked to the mmmonkey installation guide: http://www.mmmonkey.co.uk/sega-saturn-region-free-bios/

But I haven't got a 29F800 but a 29F400-IC. Apparently the pinout is different (see attachment).

In the mmmonkey guide pin 2 of the 29F800 is connected to GND. But 29F400's pin 2 is an output pin that probably shouldn't be tied to GND or VCC. So pins 1+2 of the 29F400 should be left floating? Is there a definitive installation guide / diagram for the 29F400 available?

 

You can install it exactly the same as the 800.

Or you can save yourself a wire and just cut off pin 1 and 2 and just do the 43/44 connection

 

Ok, thanks for clearing that up.

I removed the original BIOS IC by lifting each pin. Then I used a wrench to twist and remove the BIOS. The epoxy glue was quite strong...

Well, I've installed the new region-free BIOS but the Saturn seems to be dead. No video, no audio, but the disc is spinning. I rechecked and resoldered the pins again (used extra flux as well) but the Saturn doesn't work... Any ideas?

 

You didn't lift pins 1&2 and bridge pin 2 with a ground (pin13)?

 

You need to connect pin 2 (lifted) to pin 13 (not lifted). Or to the right side of the nearby capacitor.

 

x

 

The chip was from me, its properly programmed.

As mentioned, you dont need to do anything with pin2.

It will be soldering related, or a trace under the glue is damaged from you pulling it out. You should remove those chips with hot air - the heat makes it separate from the glue easily.

For the soldering, I recommend:

Plenty of flux, then put the iron between 2 legs with and back and forth motion - this helps make sure the pad gets solder and it flows from to/from the pin well. Do this for all pins.

Unfortunately as the original chip footprint is slightly smaller than the replacement flash chips, it can be quite difficult to get the pins to connect with the pads. You will get solder on the pins and it will look like you have a connection - but you dont.

 

x

 

I disagree, I have replaced many many of them and never have any problem at all getting the bioses off. I dont think you can say if someones technique is true or not, unless you have 2 identical boards and we both do it.

I have no idea what you were doing if a cap exploded, it doesnt sound like proper SMD soldering though....

 

x

 

All I can say is, I have removed A LOT of them and never had a problem. To the point where I dont even notice they are glued down until its come off.

 

x

 

done some model 2 v saturns, but I dont log serials etc. More interested in getting it done and sent back =/

And yeah, I have a lot of tools I wouldnt own if I didnt do work for other people.

 

I modded a V-Saturn before,
https://www.flickr.com/photos/48137857@N06/8094001620/

Hot air station did the job, I don't remember that there was a glue under the bios, I think only the boards with bios on the bottom layer have them(to hold securely)

 

That would make sense - if you look at the OP's photo, there are solder trap pads next to pin 1 and 40, so that part is on the side of the board that's wave soldered, and you would want to avoid using staking compound that decomposed at soldering temperatures there.

 

@bad, what temp and air speed do you set your station to, to remove the old bios. Also is there much point doing a dual bios set up? Is the region free bios UI any different to the stock one (I have a Jap model 2? [white with round buttons])

 

Ok, here's how things turned out:

I removed the regionfree BIOS and installed the original BIOS again. Saturn was still dead.

So I removed the BIOS again and checked every single trace. It turned out that the upper trace that connects BIOS pin 2 with IC8's pin 3 was broken. The lower trace to the test point was ok. It must have happened while lifting pin by pin with the needle...


Well, I repaired the trace and installed the regionfree BIOS AGAIN. Now everything works like charme. ^^

 

x

 

I'm pretty sure that only relates to the areas of the chip you can protect from being programmed (locking those sectors) which shouldn't make any difference to a Saturn bios install, long as you unprotected the chip (or it was already unprotected) when you programmed it.

I have some bottom boot chips here though, I will try and test for you