Took pics and made an OC diagram

Discuss modifications you have done or plan to do to your Dreamcast or any other hardware, or discuss devices you want to build. If your console does not work or is acting up, ask about fixing it in here.
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FamilyGuy
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Post by FamilyGuy » Wed Aug 16, 2006 11:28 pm

How many times do I have to tell you all, the 54Mhz signal is NOT the graphics clock! The graphics clock is simply drawn from the 33Mhz signal as well. The 54Mhz signal is for frame buffer.

I was told that by the person who designed the god damned "GPU".

I believe that makes the 3rd time I have said that
Maybe you're right man .. in fact I think you're right because if frame buffer increase his clock it'll go out of sync with the screen So i understand that this is plausible.. I also think that if it's the signal is the grafic clock it'll not make it go out of sync with the screen(60 hertz screen not VGA) but will only improve filtering and render time...

PURE SPECULATION

So let's say your right

but we didn't talked about this damned GPU Clock...

But i've also heard that the 33mhz signal if created by a lower signal and multiplied/amplified to 33 and to 54 for the CPU clock and the ""FrameBuffer" clock


By the way in fact all this damn 54Mhz clock do is to be too high to input it to the CPU and make us loose time talking about it

Just my opinion...

-=FamilyGUy=-

[EDIT]
HA ! and ... I also see that , overclocking the Dreamcast to 240 Mhz make the VMU not to works properly !! I think they're out of sync with the data they received !! ( if I format a vmu when verclocked it say that 15blocks are used while there's nothing in the VMU and I cant save large file .. little file have some corruption ... and file already on the VMu cannot be read properly !! .. deleting file Corupt the file you try to delete and some other file on the VMU :o )

If someone know how to fix this .. plz tell me !! :lol:

Maybe overclocking the VMu to the same ration that the CPU(20%)
But this will make a OC'ed DC only VMU ... Better than nothing !!

By the way

THANKS IN ADVANCE !!
[EDIT]

[EDIT]
Link shortened

This guy is selling a PAL OC'ed DC with a FIXED VMU ... so there's a way to fix it :P just wondering how ... he's saying
his vmu works on both OC'ed and non-OC'ed DC
[EDIT]
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Post by Nemesis » Thu Aug 17, 2006 11:21 am

I think someone who is more fluent in german needs to email him, thats a huge breakthrough if it's real.
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Post by FamilyGuy » Thu Aug 17, 2006 12:18 pm

The guy do speak english well and I will buy him a Moded VMU OR an how to manual. I'll then check what he did OR do the mod myself then , if he wants , put a Tutorial on the web.

[edit]
I got a 3dr party vmu that works 2/3 time... but dunno why ...
[edit]
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Post by Morphv2 » Thu Aug 17, 2006 4:34 pm

It is the Frame Buffer. Check Yahoo dcdev. If you aren't subscribed, I highly suggest you do:

http://groups.yahoo.com/group/dcdev/mse ... ndows-1252
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Post by FamilyGuy » Thu Aug 17, 2006 5:51 pm

Yeah I really trust you about the framebuffer thing ...
(ps : yahoo groups looks usefull... but need some reorganisation...)

But I'm still trying to fix a vmu to works on my 240Mhz DC...

-=FamilyGuy=-
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VMU FIX

Post by FamilyGuy » Sun Aug 20, 2006 11:52 am

OK !! I now know How to Fix a VMU to works properly With an OC'ed DC !!

You should Overclock it by the same ratio than the dc:

DC :200MHZ=100%
VMU :6MHZ=100%

DC :240MHZ=120%
VMU :7.2MHZ=120%

You might use aproximative Xtal rate example: 7.372MHZ will works to OC a VMU to 120%

1- open up the back pannel of the VMU
2- Locate the 6MHZ Xtal (a 3 pin Xtal near the white circle on
the board)
Image
3- Remove it
4- Solder the a new Xtal of the same ration than the DC

A 2 pin Xtal will works well:the middle pin is the ground IT might not be soldered to anything

Thanks to Doccy to have find how to overclock the vmu

-=FamilyGuy=-[/img]
Last edited by FamilyGuy on Wed Aug 30, 2006 4:29 pm, edited 2 times in total.
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Post by Sonic-NKT » Fri Aug 25, 2006 9:34 am

does this really give a performance boost in some apps? i have 3,5 Dreamcast (the half one isnt really working, doesnt read cds anymore) and i would mod one of them if it for example gives noticable better framerates in DreamSNES...
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Post by FamilyGuy » Fri Aug 25, 2006 3:30 pm

Yeah .. it increase performance of about 20% Dreamsnes is not perfect but better and DivX movies are smoother.

Dreamcast VS OC'ed Dreamcast

Here is the original benchmark video

Personally i'm going to try it to 288 mHZ and to Sync the vmu with it ...
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Post by FamilyGuy » Sat Aug 26, 2006 1:25 pm

Here's a pic of an OC'ed Vmu

It's OC'ed to sync with a 240 MHZ DC

Image
Last edited by FamilyGuy on Wed Aug 30, 2006 4:30 pm, edited 1 time in total.
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Post by Morphv2 » Sun Aug 27, 2006 2:04 pm

-=FamilyGuy=- wrote:Yeah .. it increase performance of about 20% Dreamsnes is not perfect but better and DivX movies are smoother.

Dreamcast VS OC'ed Dreamcast

Here is the original benchmark video

Personally i'm going to try it to 288 mHZ and to Sync the vmu with it ...
Haha, I uploaded that video ^_^;
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Post by FamilyGuy » Sun Aug 27, 2006 4:00 pm

You uploaded this video to Google video ?? COOL

Where did you get the delicious hardawre demo ??

I want it to do comparaison with my 200 240 288(to come) and chancast...

If it's not copyrighted of course
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Post by Zealous zerotype » Sun Aug 27, 2006 8:21 pm

I don't rember how we came in contact but it was given to me (you can see his info from the video intro) he is a pretty cool guy and I have no idea where he got the hardware demo.
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Post by FamilyGuy » Wed Aug 30, 2006 12:12 pm

ok , I'll do benchmark with Snes4All ...

I tried 288MHZ (48Mhz Xtal)

It didn't works =(
The GD-R is spinning, looking if the game is bootable and then spinning faster but I don't see anything on the screen !!

So ... Might I input some more power to the SH4 ? ( I have a spare motherboard so I can try without fearing to break it...

Thanks in advance
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Post by Sonic-NKT » Wed Aug 30, 2006 2:31 pm

isnt there something possible between 240 and 288? like around 260....
hope you gets something working, im really intrested in it.
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Post by FamilyGuy » Wed Aug 30, 2006 3:41 pm

Yes it's possible between, but I've not found any >41, <48 Xtals anywhere ... still looking ...

But I've heard that Someone (Matthemoder???) hits about 280Mhzs ...

It actually already works fine on 240MHz(40MHz Xtal)

If I find a 44 or 45 Mhz Xtal I'll be able to try it at 264 or 270 ... |/|

It should works on these lower value ...

Maybe is it just that it's un-sync with the Videocard or something else at 288 .. because The GD-R DO boot ... but there's no scrren display ...
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Post by semicolo » Wed Aug 30, 2006 4:33 pm

I've got an 44.99999 MHz TTL oscillator in stock :-p (not selling).
Maybe the video chip just can't take this much.
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Post by FamilyGuy » Wed Aug 30, 2006 4:42 pm

semicolo wrote:
I've got an 44.99999 MHz TTL oscillator in stock :-p (not selling).
Maybe the video chip just can't take this much.
:evil: Grrrr

I'll find some on ebay ... :) along with some 7.2 MHZ for the Vmu

Yeah it really might be only the video chip not being able to run at this speed ... because the dreamacst IS receiving information because you can see the gd-r spinnig scanning and then booting...

maybe some more power to the chips will fix this but .. how :roll: ??
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Post by Sonic-NKT » Thu Aug 31, 2006 12:03 pm

Does anyone know a place where i can get the needed parts in Germany?
or a shop in europe...
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Post by FamilyGuy » Thu Aug 31, 2006 1:16 pm

Look here it's really good and worldwide

http://www.ebay.com
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Post by Sonic-NKT » Thu Aug 31, 2006 8:58 pm

still cant find anything, what exactly should i search for?
what i tried just give me radios :)
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