Author Topic: RGB to Component mod using a BA7230LS encoder board design  (Read 1475 times)

DarkOnus

  • Newbie
  • *
  • Posts: 29
RGB to Component mod using a BA7230LS encoder board design
« on: January 06, 2017, 03:39:17 PM »
Hello everyone,
   I know there is a mod thread discussing a universal RGB to component mod design using member thesteve's schematic designs and basic parts here, but I'm wondering if anyone else here has tried using the SEGA-16 forum member Ace's board design, which utilizes a BA7230LS encoder IC, for their TG-16 consoles, and would like to specifically discuss that design here in more detail?

I searched and there didn't seem to be a specific thread discussing it yet, and I didn't think it would have been a good idea for me to try to discuss this design within the other thread discussing thesteve's design.

If you read my introduction thread here, Hello, and Happy New Year!, it's one reason I joined the forum since I already have several of those boards, to hopefully find answers and possibly help with my quest for improving quality while connecting my TG-16 consoles to my large screen HD TV using that BA7230LS board.

This was Ace's v5.0 schematic which the boards I am using have been designed to utilize:


These were the boards I initially purchased to populate and test this RGB to component connection, designed by member Helder using Ace's schematics:




Regards,
 ~ Craig ~

DarkOnus

  • Newbie
  • *
  • Posts: 29
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #1 on: January 11, 2017, 03:37:23 PM »
Being new here I'm not familiar on how active the membership is on a daily or weekly basis, and I see there's been a few thread views since I started it 5 days ago, but unfortunately no-one yet interested enough to comment, bummer . . . but seeing that this particular setup hasn't already been discussed here much at all previously, I was prepared that I might not get much help, if any, though I was hoping I'd get lucky and find some.  :pray:

In the meantime, to continue . . .  after receiving the boards and parts, I went ahead and hastily put one together just so I could do some testing. Unfortunately, when connected using the component output, the sync which was being stripped from the composite video signal input and mixed back into the Y channel was so far off I couldn't play anything at all. But that was my fault (I'll explain the mistakes later in detail), so after a little tweak on the initial setup (the image below shows the very long yellow sync wire I added), I was able to get the component out to work on my 73" Mitsubishi WD-73837 DLP TV. I was ecstatic, and impressed it was working so well!

Oh, and if smaller sized images or differently formatted ones are preferred, please let me know a better way to post them.

RGB to Component test setup 1:



The first mistake I made was purchasing the wrong size LM1881 sync stripper chips, as I didn't realize there were several sizes. I purchased LM1881M chips, and the board it seems were made to accept the larger LM1881N size. So in the image you can see the spider-like legs I used to solder the smaller chip to the board . . . I figure the smaller one would still work connected like this since I believe the chips are identical in all other aspects except size.

But when hooked up the original setup without adding that yellow sync wire pictured, and I didn't get sync . . .  I believed it was caused because I read one of two resistor requirements in line with the LM1881 chip incorrectly, one was listed as 680, a second as 680K . . .  I put 680 OHM resistors in both those positions, and I didn't have any 680K resistors to replace it. So instead, I just connected that long yellow wire directly from the SYNC output pin to the Y output pin.

After that sync wire was added, I immediately had a stable image, and pretty nice picture!

However, there are still some slight sync issues with some games (which seems to be typical for other mods and the same games as well), but usually for just brief moments or in certain areas, and mostly do not interfere with game play. Though I have only tried a handful of games, so I'm sure there will be more, and maybe some worse, than I've already come across.

I'll have to go back and find more and maybe I can get some photos of it, but one sure example is in the opening cut scenes in Neutopia where the lightening flash happens. Not sure anyone has gotten any component mod with 100% perfect sync on all games at all times, or if it's even possible, but I'd like to find out if there is anything I could try to possibly lessen the sync issues, even if they cannot be totally eliminated altogether.

Then there's definitely some color issues where I can hopefully find some tweaks to correct or lessen too, where some games are too dark, and colors are definitely not where they should be.

I realize taking photos of my large screen TV image while the game is running is not an ideal situation for someone else to view that image on their own monitor or TV and be able to accurately diagnose color issues, but not sure what can be done about that.

Here are a few images I had taken the first time I got the mod to work. I captured these on my cell phone, and because the TV screen is so large, the brightness of the image towards the upper or lower portions are darker than I was seeing them because of the change in viewing angle from where the camera was held and pictures taken. Pictures are also a little more blurry than what I was seeing at full size here on my screen too.

Galaga Composite :


Galaga Component :


Bonk Composite :


Bonk Component :









Keith Courage

  • Hero Member
  • *****
  • Posts: 2690
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #2 on: January 11, 2017, 04:22:59 PM »
have you tried using pin 44 off of the hu6260 for video sync?This is what is used for video sync with the other RGB to component video board. no sync stripper needed this way.

it's cool to see another possible component video board in the works. Never hurts to have more options :)
« Last Edit: January 11, 2017, 08:02:43 PM by Keith Courage »

DarkOnus

  • Newbie
  • *
  • Posts: 29
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #3 on: January 11, 2017, 11:08:32 PM »
have you tried using pin 44 off of the hu6260 for video sync?This is what is used for video sync with the other RGB to component video board. no sync stripper needed this way.

it's cool to see another possible component video board in the works. Never hurts to have more options :)

Thanks for the reply.

Just wondering, is there any real difference, besides signal length, from tapping the hu6280 sync pin 44 directly rather than what comes off the expansion port's C22 Sync pin?

If not any difference, then the follow-up question would be, do all or any of the mods tapping sync directly from the hu6280 actually have 100% perfect sync in all games, all the time?
 
I have not tried tapping directly into the hu6280 for sync. The main reason was that I wanted this to be a completely external add-on mod for the expansion port alone, without having to open and mod any console directly inside. Right now the board is not using the stripper, just the C22 Sync pin expansion port signal and has really good sync, just not perfect.




Keith Courage

  • Hero Member
  • *****
  • Posts: 2690
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #4 on: January 12, 2017, 06:15:30 AM »
oh okay, I didn't realize you were using the expansion Port. C-sync from there should be the same thing. It is 44 on the hu6260 chip.  I just find it odd that you would still need a sync stripper for it to work. Typically a sync stripper is only needed when using composite video for the sync signal.
« Last Edit: January 12, 2017, 06:21:36 AM by Keith Courage »

DarkOnus

  • Newbie
  • *
  • Posts: 29
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #5 on: January 12, 2017, 09:17:34 AM »
oh okay, I didn't realize you were using the expansion Port. C-sync from there should be the same thing. It is 44 on the hu6260 chip.  I just find it odd that you would still need a sync stripper for it to work. Typically a sync stripper is only needed when using composite video for the sync signal.

The schematics by ACE were to be able to accommodate a universal design and used on many devices, so that's why the LM1881 chips were part of it in case a system didn't have a separate sync signal to be used as input, one could strip it from the composite signal.

Now that I have learned a bit more from when I first looked into doing this mod, and knowing the TG-16 has a dedicated sync signal available from the port, I also agree with you that the stripper wouldn't necessarily be needed at all, so in another version using that same PCB setup, I just didn't populate the entire LM1881 side of the board, and tried several variations of connecting pin C22 straight to different points into the Y channel's line.

I also didn't know if there would be a difference in the sync signal stripped from the composite input and the expansion port's C22 sync pin, if they would work as well as each other, or maybe one signal would be better, so I was going to try the LM1881 and see how good the sync was . . . but without having the 680K resistors handy (still waiting for them to arrive), the stripper was doomed for failure I presume, so that's when I just decided to use the sync straight from pin C22 of the port.

I'd still like to see how the LM1881 stripped signal works with ACE's schematic designed Helder's boards anyway, without using C22 at all, and have a comparison for when I'm using sync from C22.

The things I didn't like about the design was that the board didn't have composite video out, or sound available through it, nor a way to mount the connectors I was hoping to use, so if I wanted to get everything, I had to run separate wires and add a way to mount everything in a single package . . . and that was getting a bit too sloppy for my liking.  :-&

So I learned how to just create my own PCB board layouts, made a few designs, then had one of them made up in China and sent to me to test out. I realize it will have the same color and slight sync issues as before, but I'm still glad I did it. It has everything I wanted as far as audio and video, is a lot more tidy, and the connectors are integrated into the board and very sturdy for plugging in and out often.

Here are a few images of the boards I had made and currently using :





Keith Courage

  • Hero Member
  • *****
  • Posts: 2690
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #6 on: January 12, 2017, 02:38:49 PM »
You might need to introduce a capacitor in between the C-sync and the chip for a more stable picture if you find yourself having sync issues of any sort. Maybe you already have it set up that way. A little difficult to tell by following the traces on your board.

Nice looking boards. You sure made those fast!
« Last Edit: January 12, 2017, 02:42:39 PM by Keith Courage »

DarkOnus

  • Newbie
  • *
  • Posts: 29
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #7 on: January 12, 2017, 03:13:29 PM »
You might need to introduce a capacitor in between the C-sync and the chip for a more stable picture if you find yourself having sync issues of any sort. Maybe you already have it set up that way. A little difficult to tell by following the traces on your board.

Nice looking boards. You sure made those fast!

The sync-in follows the same path as the green/Y signal, because in this version of the board the sync trace goes directly to the first 75 OHM resistor where the green signal also first connects.

I have tried cutting the sync in connector pin, then used wire to connect the pin directly to several other points of the existing circuitry in this board. Even if I connect the sync directly to the final 62 OHM resistor where Y is finally output, I still seem to get the same stable video most the time, with the exact same occasional sync issues in some games as when it goes through the entire circuitry loop from the beginning as it was intended in this version.

DarkOnus

  • Newbie
  • *
  • Posts: 29
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #8 on: January 14, 2017, 08:22:04 AM »
Can any of the forum mod gurus look at ACE's schematic I posted, and possibly offer some advice in what might be altered on this design to get a brighter image overall, for all color channels?

Keith Courage

  • Hero Member
  • *****
  • Posts: 2690
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #9 on: January 15, 2017, 05:03:19 AM »
not sure why no one else is commenting on your posts but wouldn't a more powerful transistor and or weaker resistor create a brighter image?

DarkOnus

  • Newbie
  • *
  • Posts: 29
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #10 on: January 16, 2017, 01:28:10 PM »
not sure why no one else is commenting on your posts but wouldn't a more powerful transistor and or weaker resistor create a brighter image?

It's a bummer no-one else seems to have any experience with this board at all and can share some insight. Maybe the right people just haven't come across the thread yet, or worse, no-one else is really interested enough in it to offer any comments.

I'll just keep up doing this => ](*,)  . . .  and maybe I stumble into some improvements with complete guesses, because that's all I can do with my limited knowledge in this area.

Thanks for being the lone voice offering suggestions, though I wouldn't have a clue if changing the transistors would improve or worsen the quality of the current image or not, but the issue is I don't have too many options with replacing the transistors, since the 2SC945's in it already are all I have as far as extra transistor parts lying around.

I have a fair amount of varied OHM resistors which I could try, but which resistors to replace, and what OHMs to replace them with . . . assuming I have the right one(s) to swap at all?

Keith Courage

  • Hero Member
  • *****
  • Posts: 2690
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #11 on: January 16, 2017, 04:09:31 PM »
Are those 75 ohm resistors on the input lines for the RGB signal? try cutting them down to 50 ohm. Same could also be tested for the output resistors. if that's not enough brightness with one or the other cut then lower the value again. you might get a better difference in quality with changing the input vs output resistors so you might want to test them each separately.

I am actually confused as to why there are such high value resistors on the input lines at all. Maybe that has something to do with there being a sync stripper involved.
« Last Edit: January 16, 2017, 04:11:27 PM by Keith Courage »

DarkOnus

  • Newbie
  • *
  • Posts: 29
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #12 on: January 16, 2017, 04:35:05 PM »
Are those 75 ohm resistors on the input lines for the RGB signal? try cutting them down to 50 ohm. Same could also be tested for the output resistors. if that's not enough brightness with one or the other cut then lower the value again. you might get a better difference in quality with changing the input vs output resistors so you might want to test them each separately.

I am actually confused as to why there are such high value resistors on the input lines at all. Maybe that has something to do with there being a sync stripper involved.
Yes 75 ohm resistors on each input for the RGB, though I'm a little confused why using those 75 values for RGB would have anything to do with there being a sync stripper, because in ACE's design, it's only the sync signal that goes through the stripper, none of the RGB channels. Then again, I'm not 100% sure what any of this is really doing for the signals to make it all work, lol!

I'll try your suggestion on lowering the RGB input resistors to 50 ohm, though I'm wondering if using the 75's is done or needed to the RGB channels to prepare them for going into the BA7230LS chip?
« Last Edit: January 16, 2017, 04:38:42 PM by DarkOnus »

Keith Courage

  • Hero Member
  • *****
  • Posts: 2690
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #13 on: January 16, 2017, 05:24:47 PM »
the only reason I'm saying to try smaller resistors for the input is because the PC engine has a very low RGB signal unless it is an amplified compared to other systems.

however, I'm only guessing at this point too since I haven't done anything with the schematic you're working with. Lower value resistors on the output should definitely make things brighter for sure but you'll have to try it out to see if the quality is still good because sometimes things can look washed out if the output resistors are too low. I'm just saying this based on what things I've tried with RGB amps in the past.  you may find that a 50ohm is too low and have to go with something in between like a 62ohm.

« Last Edit: January 16, 2017, 05:32:21 PM by Keith Courage »

DarkOnus

  • Newbie
  • *
  • Posts: 29
Re: RGB to Component mod using a BA7230LS encoder board design
« Reply #14 on: January 18, 2017, 04:49:53 PM »
Yes, I understand KC, and thanks for being the sole member here so far in trying to help me figure something out which might improve my experience with this setup, I appreciate it.

I set up a new board which should be a little easier for me to make changes in swapping resistors more quickly, and specifically use for testing. So hopefully this weekend I'll play around with the input resistors first, then play around with the output resistors to see what kind of results I can get.

The one thing I wish I had added in my own board design was a place for a resistor in between the Pb out and its inline 220uf capacitor, especially since there are resistors for both the Y and Pr out channels to manipulate their output in this design. I know with a little manipulation and extra effort I could add a resistor between the final capacitor and Pb out, but it won't be quite as easy as it will be with the Y and Pr channels that have the holes for a resistor in the board already.

The other thing I'm wondering is, if I added this 7314 RGB amp to create the board's RGB input from the expansion pins, rather than using the direct signals from it


 would that improve my odds of being able to produce a better image with the BA7230LS and this design? I guess I will try if playing with the resistors fails to get me the color and brightness I'm hoping I can get, especially since I already have all the parts to create that amp anyway.