RGB from Neckboard
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RGB from Neckboard
I'm trying to MOD RGB a CRT but I have some questions about this diagram (picture). Does this 1N4148 need to be a zener diode? Can it be replaced by an equivalent diode? How do I find out which one is equivalent?
About the resistor 820: I will use 3 potentiometers of 1k each, so do I really need to use this resistor 820 too?
About c-sync, should it be connected to the AV (composite) in or somewhere else? If yes, should I use it in the positive or gnd connector?
About the resistor 820: I will use 3 potentiometers of 1k each, so do I really need to use this resistor 820 too?
About c-sync, should it be connected to the AV (composite) in or somewhere else? If yes, should I use it in the positive or gnd connector?
Re: RGB from Neckboard
Thats not how we do things around here...
You won't get any help for a neckboard mod, they suck.
If you have component input then use a converter, if not then rgb mod the chassis.
You won't get any help for a neckboard mod, they suck.
If you have component input then use a converter, if not then rgb mod the chassis.
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Re: RGB from Neckboard
There's no way to use the chassis for this mod (It's not possible). I really want to use the neckboard, not the component-in, so leave it to me to decide if I'm going to like it or not, same way no one is forced to help me with this, but any help would be appreciated, so please don't ruin my chances of getting actual help.Syntax wrote:Thats not how we do things around here...
You won't get any help for a neckboard mod, they suck.
If you have component input then use a converter, if not then rgb mod the chassis.
Re: RGB from Neckboard
1N4148 doesn't look like a zener diode.
Connect sync to composite input. Connecting it to ground would just.. ground out the signal.
Connect sync to composite input. Connecting it to ground would just.. ground out the signal.
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Re: RGB from Neckboard
Is there any equivalent diode to 1N4148?Osirus wrote:1N4148 doesn't look like a zener diode.
Connect sync to composite input. Connecting it to ground would just.. ground out the signal.
Last edited by spikespiegel on Sat Aug 14, 2021 2:32 am, edited 1 time in total.
Re: RGB from Neckboard
You have 0 control over clamping and heaps of other important stuff going neckboard over component, and there is 0 difference between using rgb and component via a good converter.
Else have fun wasting time making a crap picture just so you can say your tv does RGB.
Else have fun wasting time making a crap picture just so you can say your tv does RGB.
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Re: RGB from Neckboard
Syntax wrote:You have 0 control over clamping and heaps of other important stuff going neckboard over component, and there is 0 difference between using rgb and component via a good converter.
Else have fun wasting time making a crap picture just so you can say your tv does RGB.
Cool. So long.
Re: RGB from Neckboard
I dunno. Doesn't seem hard to come by. Mouser has 500k in stock.spikespiegel wrote:Is there any equivalent diode to 1N4148?Osirus wrote:1N4148 doesn't look like a zener diode.
Connect sync to composite input. Connecting it to ground would just.. ground out the signal.
That's just for the sync combiner though. There are many other ways of combining sync. I do this: https://www.retrorgb.com/building-a-pas ... biner.html
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Re: RGB from Neckboard
This one looks interesting. Do you use it with VGA?
Re: RGB from Neckboard
You could use it with a DE-15 connector yes.
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Re: RGB from Neckboard
Why aren't any capacitors being used in the RGB cable? I was informed that they're important to avoid electrical discharge.Osirus wrote:You could use it with a DE-15 connector yes.
Re: RGB from Neckboard
I´ve been using the dodgy diode circuit for years, it works great but you need to make sure that both of the syncs are negative:
http://members.optusnet.com.au/eviltim/scart.htm
As for going to the neckboard, I have done it on a few tv´s so I can tell you that you will need to build an rgb amplifier in order to get some control over the bias and gain of the signals, because video is not standard over there. Without any way to tweak those things, it´s gonna look ranging from horrible to no usable picture at all. Also you will want to build a linear power supply or you are gonna get noise. An OSD mod is a walk in the park in comparison.
http://members.optusnet.com.au/eviltim/scart.htm
As for going to the neckboard, I have done it on a few tv´s so I can tell you that you will need to build an rgb amplifier in order to get some control over the bias and gain of the signals, because video is not standard over there. Without any way to tweak those things, it´s gonna look ranging from horrible to no usable picture at all. Also you will want to build a linear power supply or you are gonna get noise. An OSD mod is a walk in the park in comparison.
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Re: RGB from Neckboard
I forgot to mention, this application is just for vga signal, like using a computer or a raspberry pi.lukilla wrote:I´ve been using the dodgy diode circuit for years, it works great but you need to make sure that both of the syncs are negative:
http://members.optusnet.com.au/eviltim/scart.htm
As for going to the neckboard, I have done it on a few tv´s so I can tell you that you will need to build an rgb amplifier in order to get some control over the bias and gain of the signals, because video is not standard over there. Without any way to tweak those things, it´s gonna look ranging from horrible to no usable picture at all. Also you will want to build a linear power supply or you are gonna get noise. An OSD mod is a walk in the park in comparison.
Re: RGB from Neckboard
I do it using a vga signal, a console signal would be more complicated since the black level is not clamped. All in all, if you do it for image quality and you have to go to neckboard for some reason, there is no way around an amplifier since vga is too weak to drive it and you need to tweak each color line.spikespiegel wrote:I forgot to mention, this application is just for vga signal, like using a computer or a raspberry pi.lukilla wrote:I´ve been using the dodgy diode circuit for years, it works great but you need to make sure that both of the syncs are negative:
http://members.optusnet.com.au/eviltim/scart.htm
As for going to the neckboard, I have done it on a few tv´s so I can tell you that you will need to build an rgb amplifier in order to get some control over the bias and gain of the signals, because video is not standard over there. Without any way to tweak those things, it´s gonna look ranging from horrible to no usable picture at all. Also you will want to build a linear power supply or you are gonna get noise. An OSD mod is a walk in the park in comparison.
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Re: RGB from Neckboard
But what about sets without Component inputs that can't be RGB modded any other way than the neckboard? I've come across a few sets where this is the case (either they have digital RGB inputs only or they're just too old to have one at all on the jungle chip).Syntax wrote:Thats not how we do things around here...
You won't get any help for a neckboard mod, they suck.
If you have component input then use a converter, if not then rgb mod the chassis.
Re: RGB from Neckboard
You find another TV.
No one with a decent set of eyes neck mods a TV and is happy with the result.
No one with a decent set of eyes neck mods a TV and is happy with the result.
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- Posts: 213
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- Location: Seattle, WA, USA
Re: RGB from Neckboard
Sorry, but as CRT TVs are becoming harder to find nowadays without having to resort to paying $$$ to scalpers (and for some people, are already impossible to find), a lot of people are stuck with what they have, and for some people (including at least one other member of this forum) it may be a TV that's too old to have a jungle chip with any usable RGB inputs unfortunately. Sure, you may be able to at least mod such sets for S-Video, but honestly, once you see (and experience) RGB, it's really hard to go back, so for those people, S-Video really isn't cutting it anymore (Heck, some people have even labeled it as "garbage quality" compared to RGB).Syntax wrote:You find another TV.
No one with a decent set of eyes neck mods a TV and is happy with the result.
As CRT TVs with modifiable jungle chips are becoming harder to find, I think it'll eventually become important to research ways to RGB neckboard mod these older sets so that a lot more TVs are open to being RGB modifiable. I think we should appreciate what we have instead of just saying "nah" and resort to wasting time finding something that may never come up for sale in their area, because some of us really are stuck with what we have, even if it's something like a crappy old '80s TV with no RGB capable jungle chip.
Re: RGB from Neckboard
If you are that desperate to use a tube that has a chassis which does not support the video mode you desire then buy a chassis that does and fit that.
The results will be far better than any neckboard mod and cheaper too.
https://www.aliexpress.com/item/526651150.html
The results will be far better than any neckboard mod and cheaper too.
https://www.aliexpress.com/item/526651150.html