Sega Katana 5.24 Repair Notes / Need some help

So I received a Katana that wouldn't do anything basically except power on, so let's go right to it.

* Someone replaced the surface mount electrolytic caps pretty poorly as well as the through hole caps with some unknown Chinese brand of caps that were already corroding, wtf?

* No video was being displayed

* Dead HDD

* The Katana booted on all 3 lights and stayed that way.

Solutions so far:

* Replaced all the through hole caps with NIchicon 105 degree caps and touched up the surface mount caps. **Note you don't need to replace the caps in Sega stuff as they don't have the same problems as other companies do with caps.

* Socketed all of the PLCC chips that were on the Cross SCSI board and dumped them. (2 29F040 and 2 PAL chips)

* Reflowed almost all of the connectors on the board as some of them were loose.

* As for the no video, it was because of the Sega 315-6145 chip which is the video dac on the top board. These are a common problem on the Naomi machines as well (they are also on Dreamcasts). It's easy to tell if they are bad because they get hot...they aren't even supposed to be warm.

* Replaced the HDD with another SCSI HDD.

* Reflashed all of the the Katana's bios'

The katana boots up fine now, passes all tests, except the problem below

Other problems:

The GDROM drive does not work and it's not due to a bad GDROM laser assembly (as my friend transplanted the GDROM into a Naomi and it worked fine). The machine is currently in GDROM mode and not emulation as well. The light on the GDROM drive access seems to be on all the time (though it turns off if I switch the machine to Emulation mode of course) and from what I've noticed on other Development kits is it's not supposed to do that. When I open the drive and put a GDROM in it says "Checking Disc", then the disc stops spinning and the machine doesn't do anything. Even if you hit "Play" it will just stay on the "Insert Disc" screen.

Any ideas on this?

 

Sega stuff being immune to cap issues is wrong. Many Saturn's need caps replacing. As so sophias. Dreamcast and katana will be next.

Also, all caps have a rated life time. They will fail and need replacing at some point.

 

At some point yes, but not now. I'm more or less referring to leaky caps (super caps are another problem) that most arcade stuff/console stuff suffer from because of bad cap formulas.

 

I had some lightly used PC and OG Xbox mobo's that blew caps, so I can vouch for that. The PC mobo had Japanese caps that were rated for 18 years which blew on an MSI board which were military grade after 6 years. It wasn't used for those 6 years though. From what I can tell I didn't have any crazy power surges either.

The Xbox was very strong as well and then one day I took it out of storage and plugged it in and then poof, dead. It blew 5 caps close to the PSU. It was clean and stored in a dry place, no liquid stained the mobo or anything that would have pointed to any water getting on it as I stored it in a dry closet.

It could have been something else, but you never know.

 

i have seen a dreamcast a year ago that had problems power up properly and the reason was a capacitor on psu. ive told him elecrolytic capacitor will fail after time and instead of replace them all he buy a pico.

 

Yes, now. Upper Lifetime of caps is around 20 years. Also, as I mentioned - Saturn's have having this issue now and the Saturn was made by sega.

Bad formula thing is old news and gave caps that lasted a very very short time (like 2 years or so!) . Almost all of the caps you are changing today aren't related to that issue anymore, but everyone thinks it is.

Caps just fail and that's expected. The type of circuit they are in can make them fail much faster.

It's also better to change them before they leak. So I'd disagree with your assessment. However, if someone's going to change them, they shouldn't botch it - that's worse!

 

I have never owned one, but almost every Game Gear that I see has either had the caps replaced or needs them doing.

 

Pretty cool that you managed to get it t boot properly.

May i ask, what did you change the video dac with?

 

Well since it's hard to use chip quik in such a small area, it had to be a hot air station.

 

I guess I just work on more arcade stuff than console stuff as the bad caps (formula wise) still exist on many of the mid/late 90s arcade boards.
My problem with this one is the guy changed them (badly) but also used cheap chinese caps which really irritate me lol.

 

i meant, what chip did you use for the swap... if i understood correctly the one that was there was defective. Did you pull a working one from a dc?

 

Yeah, I have a ton of Naomi and Dreamcast parts. I used one off a broken DC. They are the same chips as the Naomi/DC.

 

cool

 

You are working on caps that have leaked as they are old/damaged.

The bad formula thing wasn't even a thing back then. They were made around 1999-2003 and had all failed by around 2005.

Leaking caps is how even good caps can fail. They vent and leak. it's not from "capacitor plague" But people often mix it up or still think it's all the same thing.

Sounds like I'm having a go, but it's only trying to correct the myth/misinformation.

Otherwise, sounds like you have done a great job fixing this machine up.

 

you need re cap cross board ,
I have cross stuff near 90% need re cap today

 

Katana and Dreamcast will require cap replacement soon. Those were made in late 90s-early 2000s. Those years are known for LOTS of notoriously bad capacitors.

It's like none of my 89-94 PC hardware required cap replacement, 2000 PowerBook G4 worked for at least 10 years 24/7 and still works perfectly while 2007 PC motherboard started to glitch (was starting after reset) 2 years later but it was working. Worked till 2011, when i tried to plug it in 2019 i was greeted with a black screen. When i removed (just removed) all bulged Teapo caps it booted. I have cheap 1930 tube radio in 100% orginal form - original caps are at 80-70% of nominal capacity but i had cases of 2 years old super expensive professional equipment with dead capacitors.
So the whole "company X used good capacitors, you won't have to replace them" line is nothing but utter BS. Capacitor life is limited and it depends on quality and how the device was used. Also even company known for really good caps can make a bad batch sometimes.

 

Recapped the entire board with good caps, no change in the GDROM drive. Not really sure what could be wrong with it at this point.

I attached the dumps from the SCSI board. 2 flash roms, 2 pal chips and 2 config roms for the CPLDs.

 

so , is it pass DA-TEST ? after exit DA-test , you can reset all setting,

 

It passes the DA-Test fine. I do reset everything and set it to GD-ROM mode, but it does the same thing. When you put a disc in it says CHECKING DISK, spins up for a second, then stops.

 

hmm, check the disc should be long time and keep running , did you check the GD rom flat cable is bocken? or bad connection ?
don't put disc in side , power off and power on , use R10.1 downgrade all flash , use DA-TEST to reset all, power off and on, after boot finish, let try read disc ,don't touch gd-workshop some time it suck switch GD/EMU, hope it work
if still not work, try use codescape boot to cpu mode , putr in disc than run system