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Hey everyone,
Have been lurking on this site for a few years now and has been a great amount of help.
Now I am stuck with a problem that I cannot work out.
I have an early SMS1 with a 1.3 BIOS screen. When I insert carts I get a constant Software error.
I was reading and it is to do with the BIOS checking the region.
I want to install the SMS Boot loader found on this site.
The original BIOS chip is a Sony CXK3864. I have removed that and installed a socket now.
I have a few eproms from old arcade boards.
I used a 27C512 and just doubled up the SMS Loader binary to fill the 64K.
I just get a blank screen. From what I have seen it does look like a straight swap to get the new BIOS running.
Can anyone offer any advise on getting this working? Should I use a different eprom?
Any help would be appreciated as I would like to resurrect this console.
Thanks

The error is because the system can't read the cartridge data properly. If you replace the BIOS, it won't fix the underlying problem, and games will crash or fail to start at all.

Maxim wrote

The error is because the system can't read the cartridge data properly. If you replace the BIOS, it won't fix the underlying problem, and games will crash or fail to start at all.

Thanks for that. Anywhere I should start looking to try and maybe get this thing working again?

I'm assuming you've done the usual cleaning of the cart slot and/or carts?

Do a continuity check either side of the cart slot to find bad connections/bent pins. I'd guess that one of the address lines is at fault, floating high to get the header readable but then not going low during the checksum test.

Author	Message
mamejay Joined: 31 Mar 2014 Posts: 5	Master System replace 1.3 BIOS to SMS Boot loader Posted: Mon Mar 31, 2014 10:54 am
mamejay Joined: 31 Mar 2014 Posts: 5	Hey everyone, Have been lurking on this site for a few years now and has been a great amount of help. Now I am stuck with a problem that I cannot work out. I have an early SMS1 with a 1.3 BIOS screen. When I insert carts I get a constant Software error. I was reading and it is to do with the BIOS checking the region. I want to install the SMS Boot loader found on this site. The original BIOS chip is a Sony CXK3864. I have removed that and installed a socket now. I have a few eproms from old arcade boards. I used a 27C512 and just doubled up the SMS Loader binary to fill the 64K. I just get a blank screen. From what I have seen it does look like a straight swap to get the new BIOS running. Can anyone offer any advise on getting this working? Should I use a different eprom? Any help would be appreciated as I would like to resurrect this console. Thanks

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14756 Location: London	Posted: Tue Apr 01, 2014 11:04 am
	The error is because the system can't read the cartridge data properly. If you replace the BIOS, it won't fix the underlying problem, and games will crash or fail to start at all.

mamejay Joined: 31 Mar 2014 Posts: 5	Posted: Tue Apr 01, 2014 11:09 am
mamejay Joined: 31 Mar 2014 Posts: 5	Maxim wrote The error is because the system can't read the cartridge data properly. If you replace the BIOS, it won't fix the underlying problem, and games will crash or fail to start at all. Thanks for that. Anywhere I should start looking to try and maybe get this thing working again?

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14756 Location: London	Posted: Tue Apr 01, 2014 12:36 pm
	I'm assuming you've done the usual cleaning of the cart slot and/or carts? Do a continuity check either side of the cart slot to find bad connections/bent pins. I'd guess that one of the address lines is at fault, floating high to get the header readable but then not going low during the checksum test.

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