RGB to Component mod using a BA7230LS encoder board design

[DarkOnus]

I was really curious how adding the 7314 RGB amp would affect this mod  . . . sooooo, rather then starting to play with swapping out the current resistor setups with different values to test the change in color and brightness, I decided to add the amp into the mix instead.

Still pulling all the same signals directly from the expansion port, I diverted the RGB signals into the amp, then back to the proper  Red,Green, Blue traces right at the first 75 ohm resistor. The result was either a straight black screen or a pulsing black / light blue screen, without ever seeing any amount of an actual game screen image.

I'm assuming the amp is actually working as it's supposed to, though I'm not sure how I could determine that, if anyone can offer suggestions to test the amp output, thanks. Though all I have is a typical multi-meter for testing purposes right now.

The only thing I thought I might try is swapping those first RGB 75 ohm resistors to something higher, thinking that the signal is too strong now for the BA7230LS chip to handle them after the amp.

[poponon]

hey darkonus where are you getting the boards? I'd like to get one. Have all these components

[DarkOnus]

hey darkonus where are you getting the boards? I'd like to get one. Have all these components

Are you referring to the purple Helder boards I originally used that only provide component output and the sync stripper, but have no composite video out and no audio out, or the boards I designed that have component out, with added composite video out and stereo sound, but no sync stripper?

You can purchase the purple Helder v5.0A boards at OSH Park here:
https://oshpark.com/shared_projects/5OuzFB2j

If the link above doesn't work, try searching the site for "BA7230LS RGB to Component v5.0A"

You have to register an account with OSH Park to be able to order. Minimum order is 3 boards for around $15.50, plus shipping costs.

[poponon]

awesome thanks. ordered 3

[DarkOnus]

I guess you were referring to Helder's boards then, lol.

So what system are you going to use the board on poponon?

[poponon]

I have a spare white pc engine that my friend wanted to use but he only has a newer TV. Also I wanted to build a separate universal converter that is simply scart to component. or maybe scart>15pin din>component . was meaning to build ace's board a while back but f*cked it up the first time . been wanting to do an electronics project too. i'll let you know how it works out

[DarkOnus]

For your white PC Engine, are you going to build the board for it using the LM1881 sync stripper to try to get sync?

In the beginning I mistakenly used a 680 ohm resistor instead of the correct 680K resistor for the sync stripper trace line (in the one location where 680K is designated on the board, not just 680) so I originally couldn't get any sync at all of course, but even after I replaced the 680 with a 680K resistor, the sync was really very poor anyway.

Maybe you will have better luck if you use the LM1881, and maybe I did something wrong for it not to work properly with my US TG-16 units (though I don't believe I did), but I didn't get pretty solid sync until after I started using the expansion port's Sync out pin only for sync.

This is the reason I took out the LM1881 sync stripper and all parts in that trace line and only use the Sync pin input now on my own boards.

Also, you may find that some games are just way too dark with the setup used as is for component out, and unless you can figure out an acceptable resistor configuration that will allow those darker games to be bright enough to play comfortably, without making most the other games look way too bright or washed out, it may be a good idea to have the composite video out as an option to use as well for those games instead. That's the reason I also added composite video in/out on my boards.

Here is one split screen shot of Dungeon Explorer, a game that was way too dark for me or my friends to be comfortable playing using component out using ACE/Helders board exact design, depending where in the game you are, the screens can even look darker than this tavern shot. Component on the left, and Composite on the right. Even though the image wasn't as sharp as using the component, for this game we switched to using composite out instead because it was brighter, colorful, and pretty good anyway.



 

[poponon]

DarkOnus, thanks for sharing all this information. Also thanks for mentioning composite, I'm not sure how that option escaped me lol. Just pull it off the expansion port.

I was just checking the Ace's thread on sega-16 and it sounds like people are running into similar issues in the last few pages of the thread. They were discussing a couple of fixes. I have some pots I could replace the resistors with to fiddle around with. They were also trying putting caps inline with the rgb input resistors. not sure why. I think he originally designed it to work with genesis rgb so it may be worthwhile to compare the pc engine signal to the genesis one.  I'll take a better look at my options once the boards get here and i can do some testing.

[DarkOnus]

poponon, are you going to install the board as an internal mod in your console, or are you making an expansion port plug in style mod like I have made with my boards?

[DarkOnus]

DarkOnus, thanks for sharing all this information. Also thanks for mentioning composite, I'm not sure how that option escaped me lol. Just pull it off the expansion port.

I was just checking the Ace's thread on sega-16 and it sounds like people are running into similar issues in the last few pages of the thread. They were discussing a couple of fixes. I have some pots I could replace the resistors with to fiddle around with. They were also trying putting caps inline with the rgb input resistors. not sure why. I think he originally designed it to work with genesis rgb so it may be worthwhile to compare the pc engine signal to the genesis one.  I'll take a better look at my options once the boards get here and i can do some testing.

I also read through the SEGA-16 threads on ACE's mod, as well as those same issues and possible attempts to correct them. I had a couple pots to try myself, but for me the pots seem to be really finicky and difficult to adjust accurately and individually for each channel. Just popping in various resistors for each channel was easier and more accurate for me to try, though I did not have enough various resistors to attempt to test and try dialing in better combinations until a week ago when I received a large varying resistor kit . . . unfortunately I have not had adequate time to start testing the different resistors yet.

I did join the SEGA-16 forum last November too when I was first interested in trying ACE's design, and even though my account was registered, it was only ever partially activated, so even though I could login, send PM messages to other members, I could never post, change areas of my profile and some other things.

I would have been reluctant to post there and try to discuss the mod in detail anyway because there were only ever a few brief mentions of these mods being used with the TG-16 already in the thread discussing the BA7230LS mod, and since my only interest was in the TG-16, and it's not an NEC forum, I'm sure most their SEGA loyal membership wouldn't be highly receptive to any long discussion in getting the mod to work better with a TG-16 system anyway.

I did send a PM to ACE directly asking just a few questions about the mod, and his advice if it would be OK to discuss the mod on their forum concerning its use with a TG-16 system, but I never received a response, so I just let it go. That's why I joined this forum, in hopes that others here might have tried the mod already and could start discussing it more, or maybe some members would show interest in wanting to also try it after this new discussion was opened about it, or at least would want to join in on a discussion about it if they might be able to offer some suggestions. Sadly, that doesn't seem to be the case so far, except for KC offering some possible tips, and you actually buying a Helder board to try the design yourself poponon.

So I am really anxious for you to get the boards and start your testing, and I hope you will share all your results and ongoing experience with your testing of it here in this thread with me!

I'm also still wondering, have you thought about whether you are going to internally mod your console using the boards, or make an expansion port plug-in like I have done?

~ Craig ~

PS: Oh, and if anyone was interested at all what-so-ever in trying a different board than Helder's boards on OSH Park, I have quite a few extra boards of the ones I specifically designed using ACE's schematic, they are the same as the green PCB one I posted pictures of earlier in the thread. Anyone can PM me if they need more pictures and details of the board, and if interested in trying one.

[DarkOnus]

Well, I thought there would be more interest in this mod here on the forum ,  but I it looks like I'm just about alone on this one, bummer. 

Guess I'll have to figure out things with pure trial and error. I just received some new 100 ohm pots the other day, and will use them to tweak the input and output signals for more testing. I tried using pots before, but had a difficult time adjusting the old ones to get consistent colors and brightness.

So far with the new 100 ohm pots I just got, I've had some success in getting the colors and brightness a little better and consistent by tweaking the 3 color channels on the input side with them. Need to try the output area next.

Still have no idea if trying other capacitors or transistors in place of some of the ones currently being used might help either. Though I would have no idea where to start in choosing replacements to test anyway.

I'm also going to change my board layout so there's space in the new boards for all three color channels on the input and output areas for using pots for adjustment too. Right now the space only fits resistors well in those areas. This way I can still use resistors if I want, but would have the room to still use pots instead.

[Eddiesamma]

Have you tried pull up resistors on the color channels before the i.c. ? Most rgb mods have the channels pulled up and then pulled down after the transistor/i.c.

[DarkOnus]

Have you tried pull up resistors on the color channels before the i.c. ? Most rgb mods have the channels pulled up and then pulled down after the transistor/i.c.

Sorry Eddiesamma, though I can get all the parts and put it all together any way someone directs me to, this is all new to me, so I'm not too familiar with reading/understanding schematics, the basic lingo, nor logic of how this mod works. I'm trying to learn as I go and would need advice in what exactly to do in a dumbed-down explanation to grasp what is needed.  :oops: 

Is your suggestion of using pull up resistors before the IC, which I assume are the first three signal input area 75 ohm resistors in this current setup, mean that for each color channel the one end of its resistor should be connected to voltage rather than ground (as it is now)?

[poponon]

hey darkonus sorry to leave you hanging - i've recieved the boards and just haven't got around to trying building it yet. I've got some other projects i've been focusing on right now and haven't been obeying too much. trying to catch on up on my saturn backlog heh 

[Eddiesamma]

Exactly, remove the 75 ohm in and have like 1.5 k to voltage on the input or say 5k pots to test. Then have them tied to ground on the output. Also may need some decoupling caps after the pull up resistors. So it would be R--- 0.1uf--5.3mresistor--i.c.--(maybe 220uf cap)--75ohm--Pr.