N64 RGB mod help

Started by scarmullet, March 17, 2013, 06:45:43 AM

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scarmullet

I am working on an N64 RGB mod using the THS7314 chip as an amp. I am not using SCART, but I am using a custom cable I built for my SNES, so that I can use it with my CGA to VGA adapter, (the one found in the DIY scaler kit). There is a problem, the image is too bright for my tastes, so bright it washes out the image of any detail.

I think the culprit may be the 220uF caps I have on my custom cable. What do you think?


scarmullet

Sorry for the double post, but here is a better example from Super Mario 64 that shows how bad the image is washed out.


ApolloBoy

Do you have 75 ohm resistors on the output pins on the THS7314?

scarmullet

I do have 75 ohm resistors on the AMP.

unshe

Your machine was already RGB modded?

unshe

If yes, it is possible that you got a internal booster tweak to burst a little the rgb output.
check in this page: http://www.eurasia.nu/wiki/index.php/N64RgbBooster
look at the bottom of the page.
If there, remove it.

For the THS7314 amp the 220micro farad are perfect.

scarmullet

I did the RGB mod myself.

unshe

mmm...
Did you respect the polarity of the caps?


unshe

this is what i did, maybe it can help you....

scarmullet

Yes. I am using the same cable I made for my SNES to pull RGB off it, and thats fine. Positive towards console.

I had initially soldered the RGB lines right to the chip, I moved them to the bottom holes and then touched up the pins on the chip, that way they make a solid connection, and it helped a little bit, but after a while video blinked out of the system, Composite, S-Video, and RGB...gone.

scarmullet

Quote from: unshe on March 19, 2013, 11:51:56 AM
this is what i did, maybe it can help you....

the wire joining 7 and 9, is that for a proper Cync instead of C-Sync?

unshe

#11
This board is REV-04, so no proper CSync in pin3.
I'm using Y "Luma" as source of Sync instead of CVBS (composite-video). This help whit LCDs for better quality.

The Blue wire give 12V to pin 3. So i use a gamecube Pal cable.

unshe

Quote from: scarmullet on March 19, 2013, 11:52:33 AM
Yes. I am using the same cable I made for my SNES to pull RGB off it, and thats fine. Positive towards console.

I had initially soldered the RGB lines right to the chip, I moved them to the bottom holes and then touched up the pins on the chip, that way they make a solid connection, and it helped a little bit, but after a while video blinked out of the system, Composite, S-Video, and RGB...gone.

Are you still hearing sound?

scarmullet


unshe

check the pin of VDC-nus you restored.
Try removing all the ampli mod e check if Videocomposite is still working.

scarmullet

Quote from: unshe on March 20, 2013, 03:33:40 AM
check the pin of VDC-nus you restored.
Try removing all the ampli mod e check if Videocomposite is still working.

I tried and broke off pins on the VDC...I assume it is dead.

unshe

Not good.
Can you make a very good picture of the VDC?

scarmullet

Not really, the board is scorched under the top two pins on the right side.

unshe

If you want you can send me the machine, i will try to fix. Of course for free....

scarmullet

Nah thats fine. All I need is a new VDC chip, right? Desolder, clean up the pads, solder new one on, wham bam, thank you ma'am

unshe