Clean Mod Work Thread!

I'm not sure, but I believe so. He sent me a few blanks to build up long ago to play with. I highly recommend them.

good stuff Voultar!

PC Engine RGM Mod

What to do when you're home on a sunny summer sunday?

Go to the beach! Yeah... not alone tho!

So, I was bored and decided to do a PC Engine RGB mod on my NOS Core Grafx. I feel happy and bad at the same time!
It's a never used unit. But even if I keep it or decide to part with, one day or another it had to have an RGB mod so... yeah...

Not sure if this is off topic, but does anyone know someone I could send my SNES Mini to for some mod work? I'm trying to get digital audio of out the thing, but I think I need someone to work on it properly.

Xian Xi, Voultar, Kiel

Roll the dice. They're all good on that.

Reasonably clean SuperGrafx RGB mod:



The additional orange wire you can see connected to the din is my little variation on the mod to give the correct 4:3 aspect ratio switching - but this is only applicable for European RGB Scart TV's.

Looking good.


Here is the last SuperGrafx RGB install I did a couple months ago:

Yodd said:

Looking good.


Here is the last SuperGrafx RGB install I did a couple months ago:

Click to expand...

Gotta say yours looks that little bit cleaner
I will probably be adding two blue power LED's - initial idea is to affix them using double sided tape so they give a glow from under these two vents:



That will also be an opportunity to shorten the cable lengths and redo the cable tie downs to slightly improve the overall aesthetics of the mod.

Anyone here good with custom controller cables or can recommend me someone who is (preferably in the US)? In my infinite ignorance, I bought some Undamned DB15 USB decoders for my Windy Supergun without realizing that the pinouts could be (and are) different. After doing some research, I have reasonable confidence that I could Frankenstein something together that works, but would rather have something that doesn't look heinous and make me want to throw up when I look at it.

Specific requirements and pinouts:


Willing to pay a fair price + extra for beer money.

Pretty Amy said:

Anyone here good with custom controller cables or can recommend me someone who is (preferably in the US)? In my infinite ignorance, I bought some Undamned DB15 USB decoders for my Windy Supergun without realizing that the pinouts could be (and are) different. After doing some research, I have reasonable confidence that I could Frankenstein something together that works, but would rather have something that doesn't look heinous and make me want to throw up when I look at it.

Specific requirements and pinouts:

Spoiler:

* Need 2 cables
* 3 ft. female-to-male DB15
* Would prefer black cable but other colors aren't a deal breaker

Undamned DB15 USB Decoder pinout:
1. GND
2. K3
3. Select
4. K1
5. P2
6. Right
7. Down
8. +5v
9. Not used
10. K2
11. Start
12. P3
13. P1
14. Left
15. Up

Windy Supergun pinout:
1. GND
2. K2
3. Select
4. D
5. B
6. Right
7. Down
8. +5v
9. K1
10. K3
11. Start
12. C
13. A
14. Left
15. Up
[/LIST]

Willing to pay a fair price + extra for beer money.

Click to expand...

You only need to swap three lines it seems, what does the encoder look like on the inside?

I thought I'd share some of my PCB designs!


I've designed a new RGB circuit for all PC-E variants (including Duo's) that's based around the THS7374. It differs from the THS7314 by being a 4 channel driver, in addition to being able to turn "off" the LPF that's hardwired in the THS7314. Disabling the low-pass filter yields a considerably sharper image. I use the 4th channel of THS7374 to properly drive C-Sync output, so no additional mod is needed. I have both a Duo and PC-Engine/Core-Grafx footprint designed and tested. The PC-E/CG variant solders directly to the expansion bus pinout for simplicity. This board also attenuates the output signals to .7vPP for 75 ohm loads. Meaning, the image/colors aren't washed out or are overly bright.



Also, for the OG PC-E, I've built a "proper" audio-driver for the stereo outputs found on the expansion bus. These inputs are line-level off of the pins and aren't driven. So this little board will really "wake-up" that 'ole white PC-E.



I've also designed a more competent N64RGB mod for the NS1 mainboard revisions. This board is also designed around the THS7374, which also has the sharper image output with the LPF disabled. There's an LM1881 onboard that's properly terminated to provide TTL C-Sync for N64 mainboard revisions (CPU-04) that doesn't provide a "simple" C-Sync output.

Nevermind the dodgy soldering, this is just a quick test jig that I whipped up to probe.







There's also a variant of this for the SNES 1CHIP & Mini that properly attenuates the video output to the correct level, with all of those goodies on there, too.

Does that N64 amp work on every PAL board?

It's the only system I don't have RGB. Comps(h)ite is inacceptable!

C-Sync on the NTSC system is actually voltage on the PAL system. An alteration would have to be made as there is no C-Sync output from the multi-out.

Pretty Amy said:

Click to expand...

Since two of the three are already connected, those can just be remapped, you will need however to connect the K1(9) from the supergun to pin 4 of the device.

Voultar said:

C-Sync on the NTSC system is actually voltage on the PAL system. An alteration would have to be made as there is no C-Sync output from the multi-out.

Click to expand...

well, a trace cutting and jumper wire has never hurt anybody

I would mind as long as it would warrant a nice RGB mod on my N64. I don't love the system by any means, but I can't stand playing Mario or Majora's Mask on such a crappy picture. I'm fine with the game speed as they were PAL optimized tho.

Yeah, just cut the trace and all will be well.

The board generates its own C-Sync anyways, so that's not a problem. And it's quite a nice picture. I'm not very familiar with PAL mainboard revisions, but in order for this board to work, it must have the video encoder onboard. (NS1 serial numbers here in the States)

Xian Xi said:

Since two of the three are already connected, those can just be remapped, you will need however to connect the K1(9) from the supergun to pin 4 of the device.

Click to expand...

Yeah, I was kind of hoping to avoid touching the inside of the supergun.

Voultar said:

I thought I'd share some of my PCB designs!


I've designed a new RGB circuit for all PC-E variants (including Duo's) that's based around the THS7374. It differs from the THS7314 by being a 4 channel driver, in addition to being able to turn "off" the LPF that's hardwired in the THS7314. Disabling the low-pass filter yields a considerably sharper image. I use the 4th channel of THS7374 to properly drive C-Sync output, so no additional mod is needed. I have both a Duo and PC-Engine/Core-Grafx footprint designed and tested. The PC-E/CG variant solders directly to the expansion bus pinout for simplicity. This board also attenuates the output signals to .7vPP for 75 ohm loads. Meaning, the image/colors aren't washed out or are overly bright.

Click to expand...

Does your version have the same issues with jailbars as the other bypass boards? Are the resistor fixes necessary?

The jailbars are a result of coupling on the mainboard, it has nothing to do with the amp design itself. Easily fixed, though!

In my experience jailbars are random from system to system even with the same amp. The Duo I use now had the worst jailbars I've ever seen when I first did the mod, added the cap fix and it's beautiful and clean now.

SuperGrafx Recap and RGB Install:

(Using an old Rev. of the board I designed. There's now a sync-separator on-board that can be toggled to output either TTL C-Sync or a C-Sync for 75 ohm terminations.)

Necro bump, but it's pertinent for Google searches. Here's my min-max mod work using Voultar's revision .69 board on my Super Grafx:



About as efficient as it can get. You could argue the lines to the din could be shortened a little bit, but other than that, this is about as neatly compact as you can get for an RGB bypass job on the Super Grafx. Of course I also color-coded the wires, and in order to avoid snipping the video pin for csync isolation, I just removed the R159 resistor underneath that feeds into it. Simple and clean that way.

Very nice. I want to do it.

If I ever mod my brother's Duo I'll have to use sync on composite. I have an obsession with keeping things as stock as possible, and I want the old AV cable to still work. Not that we'll probably ever use it again. My brother will appreciate that.

FBX said:

Necro bump, but it's pertinent for Google searches. Here's my min-max mod work using Voultar's revision .69 board on my Super Grafx:

About as efficient as it can get. You could argue the lines to the din could be shortened a little bit, but other than that, this is about as neatly compact as you can get for an RGB bypass job on the Super Grafx. Of course I also color-coded the wires, and in order to avoid snipping the video pin for csync isolation, I just removed the R159 resistor underneath that feeds into it. Simple and clean that way.

Click to expand...

Wow, that looks great man! Hell yeah I really appreciate clean mod work can look at it all day.