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Dreamcast HELP - Sega Katana Video & Communication problems

karlmartin95

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Hello Obscure Gamers,

In this post I will share with you the problems that I have with my Sega Katana. The post it's big so, take a cup of coffee.

Some months ago, I bought this Sega Katana from a guy in my country, he told me that the Katana was brought from Japan by him and he used it for a short time. The console gave video and all worked fine.
He stopped using the console for years, and one day he turned it on and no video signal. Because of this, I bought the console by a low price to him.

Now, once I obtained the console, I did a lot of test to it in order to know what the problem can be.

What I did:
1) I tried all the switchs configuration possible, all possible video outputs and self test mode.

2) I build a Windows 98 pc with the Adaptec 2940uw, Pentium 3 1000mhz, Voodoo 3 3000 and 512mb RAM. I installed all the SDK versions, r9, r10, r11b... because some people told me that perhaps the problem is a bad boot rom flash, so here the problems:

2.0 Introduction) The SCSI Adaptec card recognizes well the two SCSI devices from Katana, when I'm booting my WIN 98 PC I see:

ID 3: CPL KATANA DA
ID 4: CPL GD-M

And I can see one of the two partitions of the Katana's SCSI HDD in the WIN 98 PC.

2.1) DACheck gives to me this errors when I try to flash the corresponding roms:

The first time I open Dacheck. I changed the DA mode from CPU to OS but nothing happens... no video signal again.

436


When the program loads:

437


When I do a test on DA:

438


Once I select the device SCSI device:

439


Here the logs: DA Log & GDM Log

2.2) CodeScape. When I open CodeScape this message appears on screen:



And if I do soft and hard reset and hit retry in the next message



I see the Ram memory map (I guess) of the Sega Katana. I can edit some memory addresses but not all.



2.3) DBFlash. With this utility you can reflash the DA, GDM firmware and the Boot Rom, but I have the same stub error that before and I can't even see the firmware of DA, GDM and Boot Rom.

441


3.0) Hardware Check. I disassembled the console and I checked all the boards for capacitor corrosion, bad joints, and I found nothing.

Here you have the collection of images, all uploaded in Imgur posts.

Main Motherboard

Cross Products Board

The Main Motherboard is the 5.16 version but the case says 5.24, very rare and this motherboard has a switch configuration inside, I don't know the configuration and what it does.

3.1) Katana Working. The Sega Katana turns on fine, the GD Drive works and the HDD too. Here you have two videos to watch:

Katana Working without HDD

Katana Working With HDD

So, that's all the errors I could document. Please, I need your help, I want to use this devkit to learn more about the Dreamcast's architecture and to help the Homebrew community, but with these errors I can't do anything good.

I hope that I'll find a solution. I live in Argentina, so... I can't send my Sega Katana to another country.

Thanks to all for create this beautiful community! I'll wait for your answers.

Have a good day.
 

T_chan

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first thing to do is to get rid of the "full stub" not loaded.
- if the SW4 (most right dip switch of the DIP SW. on the front) is in position down, and you booted, and you got this message, this probably means that you need to reflash the soldered (erasable) bios.
Try this then:
- boot with SW4 in position UP.
- when the devkit is booted up, and your Windows system is running, put the SW4 in position DOWN, and the switch to allow reflashing to the right.
- launch DACheck to see if you got rid of the "full stub" error
- if yes, launch DBFlash & reflash the BIOS.
- be sure to respect a delay of 1 minute or so (don't remember the time) of the devkit being fully powered down after reflashing
- put the switch back to "no reflash" & SW4 to down
- restart the devkit
- retry DACheck to see if the "full stub" error disappeared -> if yes, you now have a working bios again on your devkit :)
 

karlmartin95

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(...)
- retry DACheck to see if the "full stub" error disappeared -> if yes, you now have a working bios again on your devkit :)
I tried all that you said but no luck. I turned on the Katana with rightmost dip switch ON and slide switch to right, went to DACheck and same stub error. When DBFlash loads I can't see anything, like the image in my first comment. I saw the log that DBFlash generates and say this:

DBFlash Log

As you can see, the problem is when the program tries to change CPU mode the Katana. When the program is loading, I can see the led in the front panel turned on.

*My knowledge tells me that the SMD Capacitors that are in the Main Board, close to the cable that connects the CrossProducts board with the Main Board, are failing. I don't see leakage or corrosion.

These two capacitors I'm talking about, just next to the connector of the CrossProducts board.

It's what I think. Perhaps, I'm wrong.
 
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HI_RICKY

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if you not looking resell it, let try replace all Capacitors , coz it not easy find out under smd is leak
 
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T_chan

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One extra thing you can maybe do before recapping, is to check the detachable selftest eprom.
- Detach it, put it in a universal programmer, and try to read/dump it. Check the checksum, it should be identical to what's written on the sticker. According to your photos the checksum should be 75E8.
- If that's not the case, keep the dump safe somewhere & replace the chip by a new one that you reflash with a correct selftest program. They can be bought for very cheap, it's the same chip as a Naomi Bios, an ST M27C160-100F1.
 

karlmartin95

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One extra thing you can maybe do before recapping, is to check the detachable selftest eprom.
- Detach it, put it in a universal programmer, and try to read/dump it. Check the checksum, it should be identical to what's written on the sticker. According to your photos the checksum should be 75E8.
- If that's not the case, keep the dump safe somewhere & replace the chip by a new one that you reflash with a correct selftest program. They can be bought for very cheap, it's the same chip as a Naomi Bios, an ST M27C160-100F1.
Ok, but if that eeprom is bad, why the console doesn't give me video signal? that isn't the bios rom.
 

T_chan

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As mentioned above, your (soldered) bios probably needs reflashing.
But to do that, you need to be able to communicate correctly with the devkit.
But to do that, the system needs to be able to load the full extended debug stub.
But to do that, you either need at least a working bios (which doesn't seem to be the case), or,
if your bios is not ok, you need at least a working selftest chip...

It's just a possibility... not saying that it covers all cases of "extended stub not loaded".
 

karlmartin95

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As mentioned above, your (soldered) bios probably needs reflashing.
But to do that, you need to be able to communicate correctly with the devkit.
But to do that, the system needs to be able to load the full extended debug stub.
But to do that, you either need at least a working bios (which doesn't seem to be the case), or,
if your bios is not ok, you need at least a working selftest chip...

It's just a possibility... not saying that it covers all cases of "extended stub not loaded".
Sorry but do you know what programmer should I need to test the eeprom? The chip has 42 pins and the standard programmer has 40 pins.
 

T_chan

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As a general rule:
- you note down all the chips you want to be able to read / write, on all the devices you want to support now & in the future.
- you check the list of devices supported by a certain universal programmer.

Eg: if you are only interested in the removable chips on the SET5, it needs to support:
- ST M27C160-100F1 for the mainboard
- PALCE 22V10H-15JC/4 for the DA-CDM board

Examples of cheap programmers that are often cited:
- TL866II Plus -> nice programmer, but doesn't support the SET5 chips ( & not enough pins)
- TOP3100: both chips are supported & it supports 7400 devices -> it's what I bought (only really tested with the M27C160 chip),
but there are certainly better devices...
 
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