Sony KV-FX29 100Hz

CPC6128 · Post by **CPC6128** » Mon Oct 05, 2015 4:59 pm

Hi,

A person gives me a Sony KV-FX29TA of 1988.

Only problem this magnificent TV is the first Sony to be equipped with the 100Hz!
Seen the weight and the size, I hesitate, I plan to use him only for the retrogaming.
I believe that it is impossible to deactivate in a software way the 100Hz.
I have never possessed TV 100Hz, but I read that was terrible for the retrogaming, why?
I shall like having your notices.

Thanks

kamiboy · Post by **kamiboy** » Mon Oct 05, 2015 7:23 pm

Try a 240p system on it. If you can see scanlines then you should have nothing to worry about.

That being said, I am quite baffled that 100hz existed as early as 1988.

Xyga · Post by **Xyga** » Mon Oct 05, 2015 7:41 pm

Quite the rare monster you have here: http://obsoletetellyemuseum.blogspot.fr ... -1988.html
Not sure I get what it's doing to the signal exactly, apparently it's got two modes ?
Unique design apparently.

nissling · Post by **nissling** » Tue Oct 06, 2015 6:12 am

CPC6128 wrote:I have never possessed TV 100Hz, but I read that was terrible for the retrogaming, why?

A 100Hz tube (and 120Hz as well) scan each line twice. In other words the tube will only have half as much time to draw the information as a typical 50Hz or 60Hz tube. Pro is reduction of flickering. On the other hand you will most likely notice that the amount of detail is reduced compared to a 50Hz CRT.

Ed Oscuro · Post by **Ed Oscuro** » Tue Oct 06, 2015 7:18 am

The real downside is that there must be some buffering method to draw the screen a second time, since it's not just drawing the beam as it's received (as a normal CRT will do), and therefore some lag, at least one frame's worth.

kamiboy · Post by **kamiboy** » Tue Oct 06, 2015 7:33 am

240p signals are sort of a hack, one which does not work very well with the way 100hz processing works. The exact reason why is very technical. But, as I said, if you can see "scanlines" when viewing 240p on that tube then you should be good to go.

CPC6128 · Post by **CPC6128** » Tue Oct 06, 2015 1:26 pm

Thank you for your explanations, I will keep you informed if I take it

CPC6128 · Post by **CPC6128** » Fri Dec 04, 2015 7:31 pm

Here is finally photos (of quality mediocre) take with a smartphone.

I opened the TV to adjust the image at best, there is however a small upper left gap.
I connected in RGB a super famicom APU-01.
I let you judge, personally I find picture is magnificent.
In spite of the 100hz, scanlines is present and I noticed (at the moment) no difference with a CRT not 100hz.

Hébergé par Imagesia, le meilleur hébergeur d'images du net !

BuckoA51 · Post by **BuckoA51** » Fri Dec 04, 2015 7:41 pm

I'd love to test that for lag somehow, looks like a lovely set other than the possibility of some input lag.

Xyga · Post by **Xyga** » Sat Dec 05, 2015 1:52 pm

Looks like it doesn't destroy the 240p picture, like most 100Hz do.

Sorcery !

Exidna · Post by **Exidna** » Mon Dec 07, 2015 9:33 am

Scanlines or no, the problem with 100/120Hz displays is that doubling the refresh rate results in double-images when things move across the screen.

60Hz:

120Hz:

Ed Oscuro wrote:The real downside is that there must be some buffering method to draw the screen a second time, since it's not just drawing the beam as it's received (as a normal CRT will do), and therefore some lag, at least one frame's worth.

Not necessarily. Surely you could simultaneously buffer and display an image at the same time.

Ed Oscuro · Post by **Ed Oscuro** » Mon Dec 07, 2015 10:13 am

If you can split the input path, but then you likely have to deal with a variety of issues including a possible timing mismatch (as you'd have to alternate display from the incoming signal and the buffer). I'm no engineer but it seems that Sony just fed the signal straight into a buffer, and read from it twice. Pretty straightforward, but in this case the lag is unavoidable.

CPC6128 · Post by **CPC6128** » Mon Dec 07, 2015 9:01 pm

Exidna wrote:Scanlines or no, the problem with 100/120Hz displays is that doubling the refresh rate results in double-images when things move across the screen.

120Hz:

I have not this problem with my sony.
It's identical to a CRT 60Hz, flicker in less.

...even without any digital enhancements still present in much more recent models with sophisticated chipsets.

Any model with 100HZ scan tech coming after this SONY KV-FX29 ta is a different model and technologically different.

Ed Oscuro · Post by **Ed Oscuro** » Mon Dec 07, 2015 9:20 pm

According to the blog linked earlier:

In a first operating mode, each field of the television signal is entered into the field store in this arrangement and read out twice at twice the frequency. In a second mode, only every second field is entered into the field store and read out four times at twice the frequency.

So, one mode does what I thought it would, but the other does "cheap deinterlacing" by throwing away every other set of fields, apparently..?

Seems to be backed up by the previous post on the tube, which has a section (if you scroll down a bit) talking about the method of converting the incoming signal to memory storage. Looks like copy/paste of details from the old patent applications.

Xyga · Post by **Xyga** » Mon Dec 07, 2015 9:38 pm

Yeah, again only speculating but I suspect this could be the only 100Hz TV to do the 240p stuff right.
And if there's lag with this set it's probably either something like 1 frame, or even 0 in that 'single field' mode.

Ed Oscuro · Post by **Ed Oscuro** » Mon Dec 07, 2015 10:39 pm

Counting one set of fields as a single frame (in 240p60) is going to cause one frame of lag with this method. No idea what they're trying to achieve in the second mode, but it looks like their deinterlacing method might be kind of primitive here.

I didn't have the patience to read through all the fake-friendly patent description text (how I hate that style of writing) but there was some description of adding or losing a scanline due to timing issues, which they submitted a fix for as well. I don't know if that would impact 240p performance or not.

Fudoh · Post by **Fudoh** » Mon Dec 07, 2015 10:42 pm

Or it just applies field doubling to 50Hz sources and leaves 60Hz sources untouched - after all it's a PAL unit.

Ed Oscuro · Post by **Ed Oscuro** » Mon Dec 07, 2015 11:05 pm

It's possible - the patent descriptions mention 50Hz flickering as the motivation behind the tech.

Exidna · Post by **Exidna** » Tue Dec 08, 2015 12:25 pm

CPC6128 wrote:
Exidna wrote:Scanlines or no, the problem with 100/120Hz displays is that doubling the refresh rate results in double-images when things move across the screen.
120Hz: http://abload.de/img/untitled-27to6e.jpg
I have not this problem with my sony.
It's identical to a CRT 60Hz, flicker in less.
...even without any digital enhancements still present in much more recent models with sophisticated chipsets.
Any model with 100HZ scan tech coming after this SONY KV-FX29 ta is a different model and technologically different.

You can't display a 60Hz signal at 120Hz without introducing double images.
At least not without using interpolation, which this TV certainly does not do. (some Philips CRTs did though)

Perhaps it switches between 100Hz and 60Hz rather than 100Hz and 120Hz though?
It should be possible to test this if you have a camera that has manual controls, using TFT Central's method: http://www.tftcentral.co.uk/articles/co ... tm#testing

kamiboy · Post by **kamiboy** » Tue Dec 08, 2015 12:33 pm

Fudoh wrote:Or it just applies field doubling to 50Hz sources and leaves 60Hz sources untouched - after all it's a PAL unit.

I think you hit the nail on the head there. This is more or less what I was suspecting from the start.

Easy to test too, just connect a PAL console from the 8-32 bit era and see whether there are scanlines or not.

CPC6128 · Post by **CPC6128** » Fri Dec 11, 2015 7:01 pm

Exidna wrote: It should be possible to test this if you have a camera that has manual controls, using TFT Central's method: http://www.tftcentral.co.uk/articles/co ... tm#testing

Unfortunately I possess only a smartphone.

kamiboy wrote: Easy to test too, just connect a PAL console from the 8-32 bit era and see whether there are scanlines or not.

Now I have only consoles 60Hz, but as soon as I would have a PAL console, I shall make the test and I shall send pictures.

I made a small video, maybe it can help you to know if the image is 120Hz or 60Hz.
https://www.youtube.com/watch?v=qTVDuMd ... e=youtu.be

Fed · Post by **Fed** » Mon May 19, 2025 10:30 am

Did we ever get to figure out how 240/60 is treated by this set ?

shmups.system11.org

Sony KV-FX29 100Hz

Sony KV-FX29 100Hz

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