aes RGB mod in UK

parodius

parodius

n00b
Joined
Aug 12, 2003
Posts
45
What mod are ou talking about ?
The AES does RGB out of the box, you just need to buy/make an RGB SCART cable for it.
 
MKL

MKL

Basara's Blade Keeper
20 Year Member
Joined
Mar 8, 2002
Posts
3,686
I think he refers to the mod I showed him last week:

PAL60.jpg


It's pretty straightforward but I made some schematics:

Code: 
             |               |
             |      GND      |
             |  5v        G  |
             |               |
             | A     B     C |
             |               |
             |   R       S   |
   __________|_______________|______________________
  |          |      A/V      |
  |          |      port     |
  |          |_______________|
  |
  |         A   R   B   G   S   C
  |         \   \   \   \   \   \
  |         /   /   /   /   /   /
  |         \   \   \   \   \   \
  |    G____/   /   /   /   /   /
  |    N  15k  68  68  68  68  68
  |    D
  |                                     1  x  x                   10     x  x              x  x     21
  |      O O O O                        G  R  R  G  R  R  R  R  R  G  G  B  B  B  G  B  B  G  G  B  B
  |      U U U U                        \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \
  |   24 T T T T             13         /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /
  |   _|_|_|_|_|_|_|_|_|_|_|_|_         \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \  \
  |  |   R G B C               |        /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /
  |N  )     sony CXA1145P      |
  |  |_ _R_G_B_ _ _ _A_A_S_S_ _|          _|_|_|_|_|_|_|_|_|_|_          _|_|_|_|_|_|_|_|_|_|_ 
  |    | | | | | | | | | | | |           |                     |        |                     |
  |    1 I I I       I O I O 12           )       LS273        |         )       LS273        |
  |M     N N N       N U N U             |_ _ _ _ _ _ _ _ _ _ _|        |_ _ _ _ _ _ _ _ _ _ _|
  |                 /  T | T               | | | | | | | | | |            | | | | | | | | | |
  |    _____)|_____/     |
  |        4.7u           \__________
  |                                  |
  |                                  |
  |L 6.8k    6.8k    6.8k            |
  |    \   \   \   \   \   \         |______________
  |    /   /   /   /   /   /                        \
  |    \   \   \   \   \   \                         |   
  |K   /   /   /   /   /   /                         | 
  |   R  2.2k G  2.2k B  2.2k                        |
  |                              160_________________|__121
  |                                |                126 |
  |                                |               sync |
  |J                               |                    |
  |                                |        LSPC        |
  |                                |                    |
  |
  |

I tapped the RGB signals directly from the source. I chose resistors 2 and 3 for R, 12 and 13 for B, 18 and 19 for G and connected them to the points marked R, G, B of the 68ohm resistors near the A/V port. Of course you have to break the original RGB lines coming from pins 21, 22, 23 of the Sony chip. I also cut the original composite line and connected pin 10 of the Sony chip (the true sync) to the composite pin on the A/V port.
I also removed the chip altogether as well as all its related component (resistors, capacitors, inductors, crystal etc.) but you don't have to...

Clear enough? If not, just ask...
You may have a different PCB layout but the above will apply to that just as well.

edit: with this mod the RGB signal will be identical to that of an MVS board, i.e. a bit too strong/bright/intense for scart TVs: therefore I've inserted 82ohm resistors in the RGB lines (in the pic they're covered by the black heat shrink). I found that 82ohm is the resistance value that gives the best results, but you can also use 100ohm and it will be essentially the same.

edit: in the scheme A = Audio (mono), C = Composite, S = Sync
 
Last edited:
MKL

MKL

Basara's Blade Keeper
20 Year Member
Joined
Mar 8, 2002
Posts
3,686
MKL said:
You may have a different PCB layout but the above will apply to that just as well.
Click to expand...

This is the different PCB layout I was talking about:
http://www.neogeousa.com/mods/images/mod15a.jpg

In this case, the 21 resistors are the same but the order is different (you can read the values printed on the board: 220, 470, 3.9k, etc.). In my scheme the order is (from left to right):

1 = 470 (G)
2 = 220 (R)
3 = 470 (R)
4 = 220 (G)
5 = 3.9k (R)
6 = 1k (R)
7 = 8.2k (R)
8 = 2.2k (R)
9 = 150 (R)
10 = 8.2k (G)
11 = 150 (G)
12 = 150 (B)
13 = 3.9k (B)
14 = 8.2k (B)
15 = 1k (G)
16 = 2.2k (B)
17 = 1k (B)
18 = 2.2k (G)
19 = 3.9k (G)
20 = 470 (B)
21 = 220 (B)

It appears that there are 3 sets of 7 resistors for each of the R,G,B signals. If you look at the bottom of the board you can clearly see that all 7 resistors of each set are connected together. A trace from each set then goes to one of the three 6.8k resistors located nearby (see pics and my scheme). So you could solder the wires to these resistors just as well (but if you do as I did the connection will be better). If you are uncertain as to which resistors are for R, G or B you can follow the traces from the 6.8k resistors to the input pins (2, 3, 4) on the Sony CXA1145 video encoder chip (see my scheme). In between the resistors and the pins you'll find a capacitor whose value is either 0.1uF (as in my case) or 1uF (the above pic).
 
Last edited:
RockstarRunner

RockstarRunner

Wind Jammin' All Night",
Joined
Mar 25, 2004
Posts
645
RGB fix

Hey,
I know this post is a bit old but i'd like to ask a couple of questions on it...

I have a revision 5-7 board, so need to make the RGB fix for that, I can see what you mean that the mod is the same but the resistors are ordered differently. Would it be at all possible to make a diagram for this board as was made for the 1-4 series? It would help a great deal.

You say you connected pin 10 of the sony chip to the composite pin on the a/v port, what was the result of doing this?

Thanks for any help.
 
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