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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 17, 2018 1:57 pm 


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MarkOZLAD wrote:

I would remove R348, R349 and R350 and use 75R terminations on the RGB lines, or leave them in place and use 300R terminations (using parallel resistancs to alter 100R to 75R)




Is having 75 ohms to ground a magic number? I've seen it everywhere and I guess it's a "standard", but not sure how it was determined and how much deviation you can have from it.
Why is 100 ohms not ideal?


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 17, 2018 2:00 pm 


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Diopter Doctor wrote:
MarkOZLAD wrote:

I would remove R348, R349 and R350 and use 75R terminations on the RGB lines, or leave them in place and use 300R terminations (using parallel resistancs to alter 100R to 75R)




Is having 75 ohms to ground a magic number? I've seen it everywhere and I guess it's a "standard", but not sure how it was determined and how much deviation you can have from it.
Why is 100 ohms not ideal?



http://www.ni.com/white-paper/3475/en/


https://learn.sparkfun.com/tutorials/vo ... viders/all


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 17, 2018 2:11 pm 


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Diopter Doctor wrote:
MarkOZLAD wrote:

I would remove R348, R349 and R350 and use 75R terminations on the RGB lines, or leave them in place and use 300R terminations (using parallel resistancs to alter 100R to 75R)




Is having 75 ohms to ground a magic number? I've seen it everywhere and I guess it's a "standard", but not sure how it was determined and how much deviation you can have from it.
Why is 100 ohms not ideal?

it's the standard impedance of the transmission lines and the feed points on display equipment, you want that to match everywhere

do some reading on the concept of "transmission lines" if you want more info on it

EDIT: syntax's first link is a good place to start :)


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Oct 18, 2018 7:13 pm 


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maxtherabbit wrote:

it's the standard impedance of the transmission lines and the feed points on display equipment, you want that to match everywhere

do some reading on the concept of "transmission lines" if you want more info on it

EDIT: syntax's first link is a good place to start :)


So I assume most game consoles (SNES in my case) is a 75 ohm source and the jungle chip/TV (the load) is a 75 ohm termination point, so we're trying to match that by adding a 75 ohm resistor to ground somewhere along the transmission line (in between the source and load). All this to prevent signal degradation and reflection within the transmission line.

That raises a few questions in my mind:
1. Why would there be anything other than 75 ohm resistors going to ground on the transmission line in a TV in the first place?
2. Since different cables have different characteristics impedances, shouldn't you use the same cable type from Console->Scart as you do from Scart->Teletext Port. I'm currently using breadboard jumper wires to connect my Scart->Teletext Port which is not the same as my SNES Scart cable. Or is this negligible?

Thanks for you guys' help so far. I'm almost done with my mod and will post results when I'm finished.


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Oct 18, 2018 11:14 pm 


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Diopter Doctor wrote:
maxtherabbit wrote:
That raises a few questions in my mind:
1. Why would there be anything other than 75 ohm resistors going to ground on the transmission line in a TV in the first place?
2. Since different cables have different characteristics impedances, shouldn't you use the same cable type from Console->Scart as you do from Scart->Teletext Port. I'm currently using breadboard jumper wires to connect my Scart->Teletext Port which is not the same as my SNES Scart cable. Or is this negligible?


The 75R termination was expected, it was never a standard. And it's for cables, normally, so inside the TV the traces on the PCB may terminate at completely different values - whatever the designing engineers liked, really. For a TV with no external (read standardised) RGB inputs, you will almost certainly need to add 75R terminations for your RGB whatever else you do.

Something that ouput RGB from a SCART port would be standard, but in the case of a proprietary multiAV port on a console engineers could again do whatever made sense to them. There are common factors, but small differences. This meant you often had to buy their cables, among other things. And different consoles in different regions output video slightly differently as well.


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri Oct 19, 2018 12:31 am 


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Diopter Doctor wrote:
maxtherabbit wrote:

it's the standard impedance of the transmission lines and the feed points on display equipment, you want that to match everywhere

do some reading on the concept of "transmission lines" if you want more info on it

EDIT: syntax's first link is a good place to start :)


So I assume most game consoles (SNES in my case) is a 75 ohm source and the jungle chip/TV (the load) is a 75 ohm termination point, so we're trying to match that by adding a 75 ohm resistor to ground somewhere along the transmission line (in between the source and load). All this to prevent signal degradation and reflection within the transmission line.

not exactly - we are adding the resistor to ground to CREATE the 75ohm termination point at the load

ideally, the cable's Z0 would already be exactly 75ohm

Quote:

That raises a few questions in my mind:
1. Why would there be anything other than 75 ohm resistors going to ground on the transmission line in a TV in the first place?
2. Since different cables have different characteristics impedances, shouldn't you use the same cable type from Console->Scart as you do from Scart->Teletext Port. I'm currently using breadboard jumper wires to connect my Scart->Teletext Port which is not the same as my SNES Scart cable. Or is this negligible?

Thanks for you guys' help so far. I'm almost done with my mod and will post results when I'm finished.


1) voltage dividers, filters, etc.

2) in a perfect world, yes all cabling would have perfect Z0=75 including the connectors and the internal wiring and the PCB traces and all that nonsense leading up to the termination point
perfect worlds don't exist, so breadboard jumper wire will just have to see us through this one - SCART is not an impedance controlled connector anyway AFAIK


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri Oct 19, 2018 10:11 pm 



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Voultar wrote:
frsj8112 wrote:
Ok, so I connected 5V to the YS pin and hooked up the RGB accordingly to the middle picture. Picture is there and RGB (if I pull out one of the colors then it's not there on the screen anymore), but it's very dark.

Do i need to change my termination resitors?


The problem is the simple fact that you're terminating your video inputs as if they are .7vpp 75ohm video signals.


They're clearly not.

Video signals, unlike audio, operate on very strict standards.

Let's look at some of the documentation you posted;

Image

See it? What's the amplitude?

An analog color signal (with the sync stripped out) is in the realm of 700mv under a 100% white load, with luma (brightness) peaked.

You have a dark screen? There's roughly a 200mv discrepancy which will yield a much darker image!


Incorrect source impedance, for this particular Jungle I/C.


hey guys, i've been away from this for far to long and want to get the monitor running in nice RGB.
can anyone give me any pointers of what to do next, shall i try and inject the RGB signal via the OSD instead?

See original post here: viewtopic.php?p=1211477#p1211477


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 Post subject: Re: TV RGB mod thread
PostPosted: Sat Oct 20, 2018 11:47 am 


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If you are worried that sending .7vpp into the jungle that expects .5vpp is an issue then you should a 60R resistor in series on each of the RGB lines console side, before any terminations.

The 60R will add to the 75R in the console(or scart cable)

1.4vpp 135R/75 =.5vpp

https://prnt.sc/l8a2e1

You'd have some 75R handy, just use that and see how it looks.


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 21, 2018 3:13 am 


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Does anyone have a schematic for a Toshiba MW14F51? I'm trying to see if I can save it with an RGB mod, but it's from 2005 & I suspect that was so late they completely dropped the chip right before they stopped production. Here's a few pictures of the insides.
http://oi64.tinypic.com/23r08r4.jpg
http://oi68.tinypic.com/o86ofc.jpg


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 21, 2018 7:34 am 



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wingzrow wrote:
Does anyone have a schematic for a Toshiba MW14F51? I'm trying to see if I can save it with an RGB mod, but it's from 2005 & I suspect that was so late they completely dropped the chip right before they stopped production. Here's a few pictures of the insides.
http://oi64.tinypic.com/23r08r4.jpg
http://oi68.tinypic.com/o86ofc.jpg


Is this 20 inch version a match?

https://www.manualslib.com/manual/11540 ... 20f51.html


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 21, 2018 10:36 am 


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Found it. Now where would I intercept the RGB from on this thing? Doesn't seem like it has a jungle chip like the trinitrons I've seen.
https://elektrotanya.com/toshiba_mw14f5 ... nload.html


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 21, 2018 7:46 pm 


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I've modded my TXD1372 to accept RGB input (following the 8-bit guy's instructions) but the image seems to be very... blue and the colors in general are washed out. Does anyone have any ideas as to what might be causing this? Composite is unaffected although I did note that it too had a slightly blue tinge to it before modification, though FAR less pronounced.


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 Post subject: Re: TV RGB mod thread
PostPosted: Mon Oct 22, 2018 3:47 am 



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wingzrow wrote:
Found it. Now where would I intercept the RGB from on this thing? Doesn't seem like it has a jungle chip like the trinitrons I've seen.
https://elektrotanya.com/toshiba_mw14f5 ... nload.html


IC601


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 Post subject: Re: TV RGB mod thread
PostPosted: Tue Oct 23, 2018 2:34 pm 


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So these JVC RGB cards I see on eBay....could one of these be used in a JVC I'art? Sorry if that's an incredibly stupid question, but I just opened my I'art av-27f802 to see if I could eyeball a jungle chip or any leaking caps (did find the chips), & there's a card on the left hand side that feeds into the back that looks suspiciously like it would work with one of these things.
http://oi63.tinypic.com/wbruxf.jpg


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 24, 2018 3:10 pm 


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MarkOZLAD wrote:
Diopter Doctor wrote:
First CRT RGB Mod for me! :D

I need some help on this Sony KV-K29MF1. (a 29" tube with sweet speakers)
link to the service manual: https://elektrotanya.com/sony_kv-k29mf1 ... nload.html
page 40 has the schematics like you'll see below.



The G3F is one djcalle and I have investigated before. We have not done a mod but we did find that some schematics list a CN103 Teletext port that could be suitable for RGB and Blanking injection.



So I finally have the Teletext injections lines soldered in and the TV is receiving RGB...
but there are a few issues I need to address.

I have fed Luminance (Y) from my scart connector into the composite video input on the back of my TV for sync. (I don't have a 4 DIN connector handy to connect into the actual S-video input at the moment and I prefer to use that over composite video). The main problem is that the RGB signal (from the teletext port) is not lined up horizontally with the Y signal on the screen creating a doubled and faded appearance because the RGB is shifted to the left. When blanking is unplugged I can clearly see the B&W image of the Y signal perfectly centered on the screen
https://www.flickr.com/photos/159678005 ... ed-public/
https://www.flickr.com/photos/159678005 ... ed-public/
Will connecting the Luminance into the proper S-video input fix this?

maxtherabbit wrote:

it's the standard impedance of the transmission lines and the feed points on display equipment, you want that to match everywhere

do some reading on the concept of "transmission lines" if you want more info on it.

we are adding the resistor to ground to CREATE the 75ohm termination point at the load

ideally, the cable's Z0 would already be exactly 75ohm


So I read into impedance matching a good bit and found that the tolerance for "acceptable" (<10% signal loss) mismatching for a 75 ohm source is about +/- 15 ohms.
So for a 75 ohm source you would need a resistor connecting to ground placed before the load to be between 60 and 90 ohms. But echoing what others have said earlier: a 75 ohms to ground is going to give you the best picture by reducing as much ghosting from impedance mismatch reflection as possible.

There's a good graph on this webpage below "reflection coefficient" if anyone wants to read about it.
https://www.electronicdesign.com/commun ... ing-part-1


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 24, 2018 5:15 pm 


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Diopter Doctor wrote:
I have fed Luminance (Y) from my scart connector into the composite video input on the back of my TV for sync. (I don't have a 4 DIN connector handy to connect into the actual S-video input at the moment and I prefer to use that over composite video). The main problem is that the RGB signal (from the teletext port) is not lined up horizontally with the Y signal on the screen creating a doubled and faded appearance because the RGB is shifted to the left. When blanking is unplugged I can clearly see the B&W image of the Y signal perfectly centered on the screen
https://www.flickr.com/photos/159678005 ... ed-public/
https://www.flickr.com/photos/159678005 ... ed-public/
Will connecting the Luminance into the proper S-video input fix this?

Are you using a 4PDT? What about routing a connection within the TV, from SCART sync pin to S-video luma pin?


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 24, 2018 6:23 pm 


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NoAffinity wrote:
Diopter Doctor wrote:
I have fed Luminance (Y) from my scart connector into the composite video input on the back of my TV for sync. (I don't have a 4 DIN connector handy to connect into the actual S-video input at the moment and I prefer to use that over composite video). The main problem is that the RGB signal (from the teletext port) is not lined up horizontally with the Y signal on the screen creating a doubled and faded appearance because the RGB is shifted to the left. When blanking is unplugged I can clearly see the B&W image of the Y signal perfectly centered on the screen.
Will connecting the Luminance into the proper S-video input fix this?

Are you using a 4PDT? What about routing a connection within the TV, from SCART sync pin to S-video luma pin?


I didn't know if that would affect my other devices that actually use that s-video port. Like my gamecube... would it cause something strange like signal reflections from the scart port?


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 24, 2018 6:37 pm 


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Diopter Doctor wrote:
NoAffinity wrote:
Diopter Doctor wrote:
I have fed Luminance (Y) from my scart connector into the composite video input on the back of my TV for sync. (I don't have a 4 DIN connector handy to connect into the actual S-video input at the moment and I prefer to use that over composite video). The main problem is that the RGB signal (from the teletext port) is not lined up horizontally with the Y signal on the screen creating a doubled and faded appearance because the RGB is shifted to the left. When blanking is unplugged I can clearly see the B&W image of the Y signal perfectly centered on the screen.
Will connecting the Luminance into the proper S-video input fix this?

Are you using a 4PDT? What about routing a connection within the TV, from SCART sync pin to S-video luma pin?


I didn't know if that would affect my other devices that actually use that s-video port. Like my gamecube... would it cause something strange like signal reflections from the scart port?

I believe that's the purpose of the 4PDT. No connection between the SCART port and the destinations at the Jungle IC, when SCART is off.


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 24, 2018 7:14 pm 


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NoAffinity wrote:
Diopter Doctor wrote:
NoAffinity wrote:
Are you using a 4PDT? What about routing a connection within the TV, from SCART sync pin to S-video luma pin?


I didn't know if that would affect my other devices that actually use that s-video port. Like my gamecube... would it cause something strange like signal reflections from the scart port?


I believe that's the purpose of the 4PDT. No connection between the SCART port and the destinations at the Jungle IC, when SCART is off.


Sorry, I misunderstood. Do you mean that the 4PDT switches between sync from scart and luminance from an s-video source which can be fed into the Y pin on the TV board?

Like this?:
Scart Sync>-----------------\
.....................................4PDT---------> TV Y input pin
S-video Luminance>______/


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 24, 2018 7:47 pm 


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Well, back there on page 3, there is talk about why a 4PDT would be more appropriate.

Quote:
- why is a 6PDT switch used? Shouldn't a 4PDT suffice? I was under the impression that we're Hijacking R, G, B and injecting 5V. What are the other 2 switches for? Just to be safe, would it make sense to add a Diode on the 5V line to make sure that 5V doesn't feed into the regular RGB generator IC or will the switch suffice as protection?


But, If I'm looking at mikemoffitt's wonderful schematic at the OP, it looks like there's 6 switched points, doing it the way ^ you have drawn out. 6PDT would provide either isolated scart input in one switch position, or would isolate the scart with native input useable in the other position.

Spoiler: show
Image


So, that is a good question - about signal reflections from the SCART port, if SCART sync->Y-pin is not switched.

:edit: obviously ground doesn't need to be switched and is probably better left continous from SCART input to chassis/frame/etc. So, guessing there's no harm in leaving sync unswitched and tapping Y anywhere ahead of the jungle, but obviously don't leave a SCART-connected device on when using the S-video port that uses the Y you tapped. I guess what you were looking at originally was wiring a separate external connector that would plug into composite or s-video inputs at the back of the TV for a simultaneous SCART+Sync connection? Sorry if I'm typing while thinking, but again also curious about whether SCART sync should be isolated when SCART is not in use.


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 Post subject: Re: TV RGB mod thread
PostPosted: Wed Oct 24, 2018 10:55 pm 



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Diopter Doctor wrote:

I have fed Luminance (Y) from my scart connector into the composite video input on the back of my TV for sync. (I don't have a 4 DIN connector handy to connect into the actual S-video input at the moment and I prefer to use that over composite video). The main problem is that the RGB signal (from the teletext port) is not lined up horizontally with the Y signal on the screen creating a doubled and faded appearance because the RGB is shifted to the left. When blanking is unplugged I can clearly see the B&W image of the Y signal perfectly centered on the screen
https://www.flickr.com/photos/159678005 ... ed-public/
https://www.flickr.com/photos/159678005 ... ed-public/
Will connecting the Luminance into the proper S-video input fix this?


Have you got a console wired for csync you could test with...or a sync stripper? Have seen similar to what you are reporting before.


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 Post subject: Re: TV RGB mod thread
PostPosted: Thu Oct 25, 2018 9:57 pm 


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Voultar wrote:
You have a nice sync input right on the Jungle I/C. Try terminating sync (with a 75 ohm load) directly to the sync input pin on the Jungle I/C.

Composite Video and Luma go through a couple of processes before the signal's handed off. This is the culprit for line day (edit:delay*). Terminating your sync source (properly) directly to the Jungle I/C should mitigate that horizontal phase delay.


I'm working on a trinitron and attempted to inject Luma sync directly into the Y input of the Jungle I/C. I forgot to connect a 75 ohm resistor to ground for proper termination but anyway, the screen didn't even respond at all (still no sync or a change, period). I tried this b/c the Luma sync (being fed into the composite port on TV) was showing through the RGB (the B&W portion) appearing as a shaded image to right of the RGB picture (which was shifted to the left, grrr!) as pictured here:
https://www.flickr.com/photos/159678005 ... ed-public/

So I soldered in a jumper wire right before the 1 farad cap that then connects into the Y input of the Jungle I/C and as I said, no reaction to the signal as I connect and disconnect my Luma sync to my newly solder jumper wire. BUT then I plugged my Luma sync back into the composite port like I had earlier and now, Shazaam!!!!
https://www.flickr.com/photos/159678005 ... ed-public/

BUT, now my regular s-video input is extremely dark and fuzzy even with my newly soldered wire disconnected (basically a free floating wire).

Any ideas what is going on?

NoAffinty: I may use a switch if it makes it easier (once I figure out this mess^^^) and I'll draw out what I think you're getting at. Thanks for your feedback so far.

MarkOZLAD: I'm using an unmodified 1 CHIP-03 SNES right now but I have a 1-CHIP-02 (w/ csync) that I can hook up.


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 Post subject: Re: TV RGB mod thread
PostPosted: Fri Oct 26, 2018 5:36 am 


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The one good screenshot looks great! Theres some schematics on page 12, where switching rgbs and 5v was being solved.

Sent from my SM-G955U using Tapatalk


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 Post subject: Re: TV RGB mod thread
PostPosted: Sat Oct 27, 2018 4:28 pm 


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MarkOZLAD wrote:
Diopter Doctor wrote:

I have fed Luminance (Y) from my scart connector into the composite video input on the back of my TV for sync. (I don't have a 4 DIN connector handy to connect into the actual S-video input at the moment and I prefer to use that over composite video). The main problem is that the RGB signal (from the teletext port) is not lined up horizontally with the Y signal on the screen creating a doubled and faded appearance because the RGB is shifted to the left.


Have you got a console wired for csync you could test with...or a sync stripper? Have seen similar to what you are reporting before.


So I put csync into the composite video input port and the picture was still slightly shifted to the left. And as far as clarity goes I didn’t perceive a difference between C sync and Luma sync.
https://www.flickr.com/photos/139721283 ... ed-public/

[quote=“NoAffinity”] Are you using a 4PDT?[/quote]
I’m not using a switch at all because I’m injecting signals into the Teletext port directly from my scart connector. I may use a switch for the blanking signal to turn it off occasionally but that’s only so I can still use the composite or s-video from another console.
Which is currently not working well ever since I tried to inject pure luma sync in between the Jungle chip and the PinP board. Any ideas as to what is happening here would be much appreciated:
https://www.flickr.com/photos/139721283 ... ed-public/
https://www.flickr.com/photos/139721283 ... ed-public/


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 28, 2018 5:48 am 


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So after a somewhat rocky first attempt, I think I more or less understand the fundamentals of modding RGB into a consumer CRT. I have an Emerson EWC0902 9" CRT lying around so I thought I might have a peek inside to see if I could try hacking RGB into it. So I found the service manual online and think I've figured out how to go about modding it except I don't know which of these three spots I should inject the terminated RGB signal into. Anyone mind taking a look?

Image


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 28, 2018 8:07 pm 


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Jaek_3 wrote:
So I found the service manual online and think I've figured out how to go about modding it except I don't know which of these three spots I should inject the terminated RGB signal into. Anyone mind taking a look?


To answer your question, the bottom right red circle is your common ground so injecting there will not work at all unless you do it on the chip side/top side of those resistors. Looking at the resistor values you’re going to need to change numbers around for everything to work. Check out MarkOZLAD’s excel sheet earlier in this thread on calculating everything. Depending what you put on your lines between your console and the TV will determine if you use either of the two top red circles you’ve drawn. You need a capacitor right before your signal goes into the Jungle chip.

I know it doesn’t tell you everything but that’s where you should start.


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 28, 2018 9:02 pm 


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Diopter Doctor wrote:
Jaek_3 wrote:
So I found the service manual online and think I've figured out how to go about modding it except I don't know which of these three spots I should inject the terminated RGB signal into. Anyone mind taking a look?


To answer your question, the bottom right red circle is your common ground so injecting there will not work at all unless you do it on the chip side/top side of those resistors. Looking at the resistor values you’re going to need to change numbers around for everything to work. Check out MarkOZLAD’s excel sheet earlier in this thread on calculating everything. Depending what you put on your lines between your console and the TV will determine if you use either of the two top red circles you’ve drawn. You need a capacitor right before your signal goes into the Jungle chip.

I know it doesn’t tell you everything but that’s where you should start.

I'm sorry to ask for spoonfeeding but could you explain to me how to calculate the resistor values I'll need? Also do you mean to say that I need capacitors for each of the R, G, and B lines before they enter the jungle chip? Why?

Also what is the disadvantage in doing what this guy did and ignoring resistor values and the like all together?


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 28, 2018 10:18 pm 



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Diopter Doctor wrote:
So I put csync into the composite video input port and the picture was still slightly shifted to the left. And as far as clarity goes I didn’t perceive a difference between C sync and Luma sync.
https://www.flickr.com/photos/139721283 ... ed-public/



What problem are you trying to solve again? Having trouble following your posts and this other guy crapping on about switches just makes it even harder. You are likely stuck with any shifting of the picture in RGB mode.

Also, G3F chassis Sony's renowned for getting blurry with age. This is not anything to do with RGB mod.


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 Post subject: Re: TV RGB mod thread
PostPosted: Sun Oct 28, 2018 10:28 pm 



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Jaek_3 wrote:
Diopter Doctor wrote:
Jaek_3 wrote:
So I found the service manual online and think I've figured out how to go about modding it except I don't know which of these three spots I should inject the terminated RGB signal into. Anyone mind taking a look?


To answer your question, the bottom right red circle is your common ground so injecting there will not work at all unless you do it on the chip side/top side of those resistors. Looking at the resistor values you’re going to need to change numbers around for everything to work. Check out MarkOZLAD’s excel sheet earlier in this thread on calculating everything. Depending what you put on your lines between your console and the TV will determine if you use either of the two top red circles you’ve drawn. You need a capacitor right before your signal goes into the Jungle chip.

I know it doesn’t tell you everything but that’s where you should start.

I'm sorry to ask for spoonfeeding but could you explain to me how to calculate the resistor values I'll need? Also do you mean to say that I need capacitors for each of the R, G, and B lines before they enter the jungle chip? Why?

Also what is the disadvantage in doing what this guy did and ignoring resistor values and the like all together?


R252, R254 and R256 are the OSD ground resistors. They are the ones I would replace with a "calculated" resistor and the 75R terminations. Same pattern as 8 Bit Guy TV.

If you want to use the existing factory OSD inline resistors, they are R249, R251 and R253, 3.3K resistors, you could use 470R or 510R "calculated" tied to the 75Rs.

Image

Another option to try is to use the 1000R in R249, R251 and R253 and 100R joined to 75R in R252, R254 and R256 as you did for the last mod.


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 Post subject: Re: TV RGB mod thread
PostPosted: Mon Oct 29, 2018 2:31 pm 


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MarkOZLAD wrote:
Diopter Doctor wrote:
So I put csync into the composite video input port and the picture was still slightly shifted to the left. And as far as clarity goes I didn’t perceive a difference between C sync and Luma sync.
https://www.flickr.com/photos/139721283 ... ed-public/



What problem are you trying to solve again? Having trouble following your posts and this other guy crapping on about switches just makes it even harder. You are likely stuck with any shifting of the picture in RGB mode.

Also, G3F chassis Sony's renowned for getting blurry with age. This is not anything to do with RGB mod.


My issue is the Luma sync (being fed into the composite port on TV) is showing through the RGB (a B&W picture shows when blanking RGB is off) appearing as a shaded image to right of the RGB picture when blanking is on. The B&W image is centered and the RGB is shifted to the left so you get this appearance:
https://www.flickr.com/photos/159678005 ... ed-public/

If I disconnect the Y transmission line that goes to the Jungle chip, the B&W image goes away and so does the double image when blanking is on.
As seen here:
https://www.flickr.com/photos/159678005 ... ed-public/

I've tried using c-sync, same thing. I think I just have to put a switch in that connects and disconnects the Y input to the Jungle chip.
Is there another way around this?

P.S.
The G3F picture is clear, it's just that the PinP board is messed up on my chassis and it was causing the Jungle chip not to get the proper voltage to work. I had to bypass the PinP board with a resistor; I have it figured out now.


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