Jaguar Console Bios Chip Replacement

[+BitJag]

Probably a simple question, but I am having a hard time verifying my assumptions.

 

I was wondering if this kit from Console 5 could be used to replace the bios chip in the base console, if the CD bios is replaced with base console bios?

http://console5.com/store/atari-jaguar-cd-encryption-bypass-bios-kit.html

 

Here is the link to the Console 5 wiki where they list the part number for the chip in the kit

http://console5.com/wiki/Atari_Jaguar_CD

 

I am trying to resurrect a console, and my technician (40+ years as a electronics technician and still practicing) says that the usual problems that Jaguar consoles run into aren't the issue in this case, after testing the usual suspects that are listed online. he suspects the bios may have been corrupted somehow at some point, after monitoring the boot process on an oscilloscope (this is all voodoo magic to me). Each time he boots the system with a game, the boot process is inconsistent.

 

He has asked me to the purchase the parts necessary to test a working bios in the system (He is troubleshooting this as a favor to me, because he hasn't worked on any Atari product since the 90's, and is mentoring me at the same time. He expects me to do a bit of the leg work for the free work and instruction he is providing).

 

First he just wants to add the socket so he doesn't have to keep soldering/unsoldering things, then he wants to try pulling the bios out of one of my working consoles, and test it in the non-working one first, to determine if the bios is really the problem. I assume that the socket in the kit will work fine, because of the same pin count and package design. But I want to make sure that the chip that comes in the kit can be used with the Jaguar bios image.

 

Also, are there any other things I should be aware of when it comes to the bios? It seems like I have read something while meandering on the webs that there are different versions of the jaguar bios for the base console. Is this something to consider?

 

Just for fun, here is the Console 5 wiki for the base jaguar console. Unfortunately they don't list an equivalent part to replace the bios.

http://console5.com/wiki/Atari_Jaguar

 

Thanks in advance for any advice that is given.

[+madman]

You can't swap the CD BIOS with the console BIOS. Different BIOS revs for the console won't matter. If he has an EPROM burner, that's probably the easiest thing to do after mounting a socket rather than removing the BIOS from your working console.

[+BitJag]

You can't swap the CD BIOS with the console BIOS. Different BIOS revs for the console won't matter. If he has an EPROM burner, that's probably the easiest thing to do after mounting a socket rather than removing the BIOS from your working console.

 

Thanks for the quick reply.

 

So, if I replace the existing CD BIOS with the base console BIOS, on the EPROM that comes in this kit, it should be a usable replacement? In an ideal world of course

[+madman]

Thanks for the quick reply.

 

So, if I replace the existing CD BIOS with the base console BIOS, on the EPROM that comes in this kit, it should be a usable replacement? In an ideal world of course

No point ordering the kit in that case, just burn the Jag BIOS to an EPROM and order a socket.

[+BitJag]

No point ordering the kit in that case, just burn the Jag BIOS to an EPROM and order a socket.

 

And just to clarify, a 27c020 will work fine? I am an amateur when it comes to this stuff. The Jag bios is 128k, and this EPROM Console 5 is using seems to be bigger according to the datasheet, 256k (I could be reading it wrong). I just want to make sure this is a non-issue before ordering.

 

Here is the datasheet I am looking at http://www.futurlec.com/Memory/27C020-10PLCC.shtml

[+madman]

Pretty sure you just need a 27c010 based on the size, hopefully someone else can chime in.

[+BitJag]

Thanks again madman. I am feeling confident about this now based on your comments and a little bit more info I was able to dig up. Time to for a bit of feline necromancy

[+rdemming]

The Jaguar BIOS is 128 KB. If you use a flash chip that is bigger then you have to make sure the higher address lines are connected to the common rail and not floating (I'm not sure how the unused pins of the original BIOS chip are connected in the Jaguar).

 

But if you use a bigger flash chip then you can also program multiple BIOS version like BJL. See the following link for inspiration.

[+BitJag]

The Jaguar BIOS is 128 KB. If you use a flash chip that is bigger then you have to make sure the higher address lines are connected to the common rail and not floating (I'm not sure how the unused pins of the original BIOS chip are connected in the Jaguar).

 

But if you use a bigger flash chip then you can also program multiple BIOS version like BJL. See the following link for inspiration.

Thanks for the info about the gotchas using a larger EPROM. I decided to go with the 128k EPROM (ordered a few just in case).

[Zerosquare]

Different BIOS revs for the console won't matter.

From my (very limited) testing:

- Using the newer version on older (CPU v1.0) consoles works fine.

- Using the older version on newer (CPU v1.1) consoles causes problems (the startup is unreliable, sometimes you only get a black screen and nothing happens).

 

You can find dumps of the ROMs here:

http://webpages.charter.net/jag-udg/

 

They're labelled "K series" and "M series", but I'm not sure that's relevant: some K series consoles use the CPU v1.1 chip.

[+BitJag]

Thanks Zerosquare, download links were going to be my next request, as most of the downloads I have been able to find don't indicate what version they are.

[Stiki]

Does anyone have a pre flashed chip for sale?

I'm very new to this and am trying to fix my console with green light but no video or sound.

If someone can point in a right direction that would be great!

Many Thanks in advance.

[Zerosquare]

Best Electronics CA may have the original ROM chip for sale (their website is a mess, if you don't find it you can ask the guy running the store thru email):

http://www.best-electronics-ca.com/

 

But this may be expensive. I'd recommend buying a blank chip, and asking someone in your region that has a chip programmer to flash it for you. There also may be people on eBay offering this kind of service.

 

Note that there are many causes that can cause the symptoms you're getting ; the ROM chip is only one of them.

[neo_rg]

If you are UK or Europe based I could help you out.

[Stiki]

Hi all,

I just wanted to say 'Thanks' to all that guided me especially Luke at Console5 whom burned a Bios Rom Chip for me and supplied all the capacitors etc.

I actually have managed to get my Jaguar console working again that was bought from eBay listed as 'Not Working'.

When plugged in & a game inserted the green light would come on but no picture or sound whatsoever, so I decided to open it up and investigate the state of the capacitors, Reg1 and U38 chips which appears to have been replaced by someone recently.

I went ahead and replaced them again and got the same result.

Almost abandoning my Jaguar I thought let me replace the Bios Rom chip and thats when I discovered a broken track beneath the chip!

What could have caused this?

No burnt mark or hole beneath the Bios Rom chip.

It looks like corrosion but how did it get there!

It could have also been caused by a catastrophic failure due to wrong power adapter being used frying the track in that particular spot.

It's not the usual place people would look.

This was my first ever fix for a gaming console so I'm over the moon ?

[rayik]

@Stiki Nice job fixing it !!

[Gummy Bear]

That trace looks like it's been abraded.