Due to a large amount of spamers, accounts will now have to be approved by the Admins so please be patient.
×
- 0
IGNORED
PC RGB to component converter & TV hack
-
Recently Browsing 0 members
- No registered users viewing this page.
Question
Zebidee
Hello Aussies, I'd like to explain how I've successfully hacked an interface board to convert PC RGB(S) output into component colour space for direct input to a TV that does not directly support either RGB or component inputs.
The PC is a very basic Windows XP64 machine (HP/Compaq core2duo E7500 3.0Ghz 2GB RAM) with an old X1050 64mb video card that outputs VGA + svideo. It is running CRT_emudriver and outputting +'ve composite sync.
The TV is a brand new Distar 21" CTV-1121 TV, built on a very common cheap generic Chinese chassis (bought in Thailand). "From the factory", it only has composite inputs. It has just one chip on the PCB, a jungle "monster" IC with OSD functions combined (8895CSN67GG9). This chip does not provide for RGB inputs at any stage. There is no RGB anywhere on this TV until you get out of the jungle and on your way to the neckboard. There were no component inputs on this TV either. However, there are IC inputs labelled "Y, Cb, Cr" at pins 19,20,21. This is where I hacked the component signal in.
Now, I know that YCbCr is a digital standard, not analogue (YPbPr), but everything pointed to this TV being able to take analogue YPbPr (component) inputs, including unpopulated PCB traces and a blanked out spot on the TV case for the plug mounts to go. So I crossed my fingers and forged ahead with the assumption that whomever labelled the IC knew little about the difference between the two standards.
I couldn't find any datasheets that exactly matched my TV's jungle IC, but I found a few hits for a very similar one, 8893CRCNG7D65, which is also made by Toshiba and identical for my intents and purposes. Somehow I found an English language pinout:
http://www.datasheetq.com/datasheet-download/871940/1/Toshiba/8895CSNG7DN5
On the TV, I traced the unused jungle's Y/Cb/Cr inputs back to where they were terminated with 0.1uF capacitors and 100R resistors to ground. This is where component inputs would have been fed into the jungle, if they existed. Instead of soldering directly to the jungle chip, I figured it'd be much better hacking my inputs in here.
I carefully lifted the legs of the caps from the PCB (ie out of circuit), and added my component input wires there (ie nothing between my wires and the jungle "monster"'s component inputs).
[ATTACH=CONFIG]138354[/ATTACH]
I then connected a RGB2component circuit that I've been playing with, between the PC's VGA RGBS out and the TV's new component inputs (see below).
I've put up some screenshots below. If sometimes they seem a little dark, it is because I was focused on trying to capture "pixelation" or sharpness (in any case, I can still adjust the brightness/contrast, just like in a normal TV), which means my ancient iPhone 4S camera automatically used a small aperture (ie darker) to minimise "blooming" from bright areas.
You'll see that the image is a currently a little too wide - I will want to make some TV adjustments and tweak my video modes in CRT_emudriver.
Next post: Zebidee's RGB2component hack
Edited by ZebideeLink to comment
Share on other sites
Top Posters For This Question
35
18
12
10
Popular Days
Nov 10
9
Jul 21
6
Nov 9
5
Jan 28
4
Top Posters For This Question
DekDek 35 posts
Zebidee 18 posts
MarkOZLAD 12 posts
buttersoft 10 posts
Popular Days
Nov 10 2018
9 posts
Jul 21 2020
6 posts
Nov 9 2018
5 posts
Jan 28 2020
4 posts
Posted Images
79 answers to this question
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now