RGB horizontal shift control?

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andykara2003
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RGB horizontal shift control?

Post by andykara2003 »

Hi all, been away for a while so I’m a bit out of the loop. As everyone knows, using RGB scart on a consumer CRT often will result in an image that’s shifted to the left compared with using other inputs. I’ve set the horizontal position pot on my consumer trinitron to move the image to the right as far as it’ll go, but it’s still a bit too far to the left.

Is there a unit out there that can give additional control to the horizontal position of the image so I can get it centered?
hellbelly
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Re: RGB horizontal shift control?

Post by hellbelly »

There sure is. I believe it’s an adaption of one of Tim Worhingtons projects - http://members.optushome.com.au/eviltim/other/other.htm

I tried to make one myself but failed, I want to return to it one day.

But in the meantime, I picked up one of these -
https://a.aliexpress.com/_BSAfzL

Pete
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

hellbelly wrote:But in the meantime, I picked up one of these -
https://a.aliexpress.com/_BSAfzL

Pete
Thanks that looks great! Is there any degradation to the image or is the output just as good as with direct RGB?

PS. you’re mmmonkey? I’ve seen your stuff around for years - very useful info, cheers :)
hellbelly
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Re: RGB horizontal shift control?

Post by hellbelly »

Cheers :-)

I’ve not noticed any degradation of image quality. I bought it for a Panasonic CRT I have which has a lovely image but after adjusting the H shift the image still couldn’t be centred, this sorted it though.

Also tried it on a B&O and a JVC BVM style set just to check compatibility and it was fine.

Now as you m typing this, I realise I haven’t checked the voltage on the Sync signal to see if it’s still in spec. But I only have a cheap DIY scope and still not learnt how to use it. Hmmm.
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

hellbelly wrote:Now as you m typing this, I realise I haven’t checked the voltage on the Sync signal to see if it’s still in spec. But I only have a cheap DIY scope and still not learnt how to use it. Hmmm.
Nice one, good to know the image is decent - but if the sync is slightly is out of spec, is it still possible the unit could damage my TV?
Last edited by andykara2003 on Tue Nov 17, 2020 10:09 am, edited 2 times in total.
hellbelly
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Re: RGB horizontal shift control?

Post by hellbelly »

I’m no expert, but that is what I’ve been told. I’ll dig my cheapo scope out this week and see if I can figure it out. I need to know now if it’s safe - I’ll see if I can find someone in the UK who could test it for me on some proper equipment.
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

hellbelly wrote:I’m no expert, but that is what I’ve been told. I’ll dig my cheapo scope out this week and see if I can figure it out. I need to know now if it’s safe - I’ll see if I can find someone in the UK who could test it for me on some proper equipment.
Nice one, that’d be great :) I’ve messaged the seller as well to see what he says (and to make sure it’s not TTL), & will post his answer back here..
MKL
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Re: RGB horizontal shift control?

Post by MKL »

andykara2003 wrote:I’ve set the horizontal position pot on my consumer trinitron to move the image to the right as far as it’ll go, but it’s still a bit too far to the left.
There is a jumper or a lever to further adjust the horizontal centering.
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

MKL wrote: There is a jumper or a lever to further adjust the horizontal centering.
Ahh interesting - would that be next to the pot? It’s a BE-2A chassis - if I took some photos of the board would you be able to identify which jumper/lever that would be?
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Gunstar
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Re: RGB horizontal shift control?

Post by Gunstar »

Another DIY RGB shifter here: https://playoffline.wordpress.com/cable/rgbshifter/
Image

Seems to be based on some swiss device released in the early and late 90s.
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Re: RGB horizontal shift control?

Post by MKL »

andykara2003 wrote:
MKL wrote: There is a jumper or a lever to further adjust the horizontal centering.
Ahh interesting - would that be next to the pot? It’s a BE-2A chassis
No, it's easier to reach, the three pin header halfway along the rear side (in between the yoke header and a heat sink).
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

Gunstar wrote:Another DIY RGB shifter here:
Funnily enough, I already have one of these, albeit in a different casing. Trouble is it creates a flickering distortion towards the top and sometimes centre of the image. This distortion is actually mentioned in the text of that page you linked to:

“ Due to the technical conditions of the various television models, distortions can occur at the top of the screen. This unsightly side effect can be eliminated by changing the switch position from A to B (not with 480i or 576i signal source).”

Unfortunately no combination of settings on my unit eliminates this, which is why I’m looking for an alternative. The ideal solution would be the one MKL suggested which would be a jumper or lever on the TV’s board to further adjust the position as that would need no extra electronics, keeping the signal as clean as possible, but I’ve no idea where that would be. I’ll take the TV apart soon & have a look. Failing that, I’ll buy the unit hellbelly suggested and hope it doesn’t give the same distortions as my unit.

Here’s mine:

Image

Image
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Gunstar
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Re: RGB horizontal shift control?

Post by Gunstar »

andykara2003 wrote:
Gunstar wrote:Another DIY RGB shifter here:
Funnily enough, I already have one of these, albeit in a different casing. Trouble is it creates a flickering distortion towards the top and sometimes centre of the image. This distortion is actually mentioned in the text of that page you linked to:

“ Due to the technical conditions of the various television models, distortions can occur at the top of the screen. This unsightly side effect can be eliminated by changing the switch position from A to B (not with 480i or 576i signal source).”

Unfortunately no combination of settings on my unit eliminates this, which is why I’m looking for an alternative. The ideal solution would be the one MKL suggested which would be a jumper or lever on the TV’s board to further adjust the position as that would need no extra electronics, keeping the signal as clean as possible, but I’ve no idea where that would be. I’ll take the TV apart soon & have a look. Failing that, I’ll buy the unit hellbelly suggested and hope it doesn’t give the same distortions as my unit.

Here’s mine:

Image



Image
Interesting, that saves me building that then! Strange that you get distortion, I wonder why that guy I linked doesn't. I actually have a BE2 chassis I need to adjust too (move to the right) and I only saw one-pot mentioned in the service manual for horizontal shifting so keeping an eye on this thread in case its something I need to mess with.
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

Gunstar wrote:Strange that you get distortion, I wonder why that guy I linked doesn't. I actually have a BE2 chassis I need to adjust too (move to the right) and I only saw one-pot mentioned in the service manual for horizontal shifting so keeping an eye on this thread in case its something I need to mess with.
From the text I’m thinking some models/brands work fine & others just don’t, unfortunately including the BE-2B chassis.

I only just say MKL’s last post, going to check that out tomorrow..
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

MKL wrote:No, it's easier to reach, the three pin header halfway along the rear side (in between the yoke header and a heat sink).
Thanks very much, will check it out ASAP :)
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

MKL wrote: No, it's easier to reach, the three pin header halfway along the rear side (in between the yoke header and a heat sink).
Excuse my ignorance, I’ve looked it up and can’t work out what a yoke header is. I’ve had a look & the only 3 pin header I can find is on the yolk board as pictured, but it’s not near a heat sink. Would you mind casting your eye over these & pointing me in the right direction?

Image

Image

Image

Image

Image
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Re: RGB horizontal shift control?

Post by MKL »

Oddly, the parts for the horizontal centering circuit are not mounted on your TV (what model is it?):

Image
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

MKL wrote:Oddly, the parts for the horizontal centering circuit are not mounted on your TV (what model is it?):
Ahh shame, thanks for checking. It’s a kv-m2151u. It’s an odd one as the case looks late 90s but the chassis has no service menu as far as I can tell and is only adjustable with pots.
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Re: RGB horizontal shift control?

Post by MKL »

It's from 1993. Even the schematics show the circuit is missing. The parts can probably be added:

Image
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

MKL wrote:It's from 1993. Even the schematics show the circuit is missing.
Ahh, never mind. Thanks v. much for putting yourself out & looking into it, much appreciated :)

Oh well, I’ve ordered the unit hellbelly (thanks!) suggested. I contacted the always delightful Yossi of the behar bros and he pointed me to this same unit as well, although he doesn’t know how good it is. I’ll be very interested to see hellbelly’s test results. Hopefully the sync’s OK..

It did occur to me though, I wonder if it’s possible to get the Extron 201/3 RXi to do this? It has horizontal and vertical centring & I have one knocking around, but I don’t know if there’s any way to get it to accept a 240p RGBs signal. I have a feeling the answer is no..
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Re: RGB horizontal shift control?

Post by hellbelly »

@andykara2003 - interesting Scart switch box, that’s the exact one I was hoping to incorporate my DIY one into if I ever managed to get it working!
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

hellbelly wrote:@andykara2003 - interesting Scart switch box, that’s the exact one I was hoping to incorporate my DIY one into if I ever managed to get it working!
It’s a really smart high end feeling unit being metal with a nice finish, I think you’ll like it. I had a look at that circuit in your link - I’d be curious to see how it turns out..
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buttersoft
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Re: RGB horizontal shift control?

Post by buttersoft »

hellbelly wrote:There sure is. I believe it’s an adaption of one of Tim Worhingtons projects - http://members.optushome.com.au/eviltim/other/other.htm

I tried to make one myself but failed, I want to return to it one day.

But in the meantime, I picked up one of these -
https://a.aliexpress.com/_BSAfzL

Pete
Hey, same! I laid out Tim's circuit and ordered a PCB, which i'm pretty sure is perfect, but it doesn't work. Doesn't do anything funky, it's just dead. I haven't gotten around to scoping it, but i'm kinda wondering if i bought some bogus/knock-off IC's or something.
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Re: RGB horizontal shift control?

Post by Taiyaki »

It's not just on consumer crt's, but also on pvm and bvm sets as well. The best thing I could find is to use rgb on all systems other than the ones where component is a must such as the gamecube and the wii. Fortunately the Wii and the Gamecube has horizontal shift controls in the menus, so you can safely adjust your tv to rgb settings and all should be more or less centered. Some consoles will require modding to get rgb such as the NES and N64. For Groovymame on a pc, you can also adjust within the software which is great.
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Re: RGB horizontal shift control?

Post by Fatass »

Hellbelly, can I ask what consoles you had hooked up to the aliexpress scart shifter? And did the rgb scart cables have sync strippers in them?

I've not had much success with most image shifting devices on my consumer crt and I've tried both an extron 201 rxi and otaku games' recent scart switch model with the image centering knobs. The image I get can be moved around but then I get tearing, flagging or some screen jiggle instead. Solves one problem, gives another.

It sounds like that aliexpress one just might be the way to go (?).
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Re: RGB horizontal shift control?

Post by hellbelly »

I’ve tried these NTSC consoles...

SFC 1 chip using 7474 bypass and restored csync.
Regular SFC using native csync.
Saturn using sync on luma cable.
N64 with 7374 RGB mod and csync.

Not sure I’ve got anything with a sync stripper built in to try.

Is there any consoles in particular that I could try?

Also, I’ll try and find my scope out tomorrow, it wasn’t where I thought it was.

Pete
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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

hellbelly wrote:Is there any consoles in particular that I could try?

Also, I’ll try and find my scope out tomorrow, it wasn’t where I thought it was.

Pete
Cheers for doing that, very good of you. The SNES & N64 are my concerns so good to know they’re fine. Aliexpress says I should get my unit mid December so a bit of a wait. & interested to hear what your scope says, that stuff’s beyond me but it’d be reassuring to know it’s safe. The unit looks well put together and professionally done so I’m hopeful they got the sync right..
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Re: RGB horizontal shift control?

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andykara2003
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Re: RGB horizontal shift control?

Post by andykara2003 »

emphatic wrote:Arcade Forge just released this: http://arcadeforge.net/Pi2Jamma-Pi2SCAR ... ZRxOnXH0xw
Ahh OK arcade forge are very good and a known quantity. I’m not versed on sync, but I’m assuming the sync level is for consumer CRTs rather than TTL.

Does anyone know what they mean by this:

“Sync resistance of 75 Ohm can be switched on and off with a jumper”

And does setting it wrong damage the TV?

Out of interest I might possibly buy this too , although the advantage of the Aliexpress unit is that it does vertical adjustment as well.
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Re: RGB horizontal shift control?

Post by kitty666cats »

andykara2003 wrote:although the advantage of the Aliexpress unit is that it does vertical adjustment as well.

For some reason I forgot the Ali one did that til last night. Popped one on my 'Xmas list' even though I don't need one all that bad, heh. Neat little things, I found them a couple months ago and have NO idea where they originated
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