DIsabling 100Hz on a large Thomson CRT TV ?

[mutmut02]

Hi

A co-worker has in storage a Thomson 37MH44E (ICC19 Thomson chassis) that he is going to dump. I'd be quite willing to get it for my setup, especially as this used to be a high end TV. Sets that large are quite uncommon to get as well in my area and I'd love to get it.

But after a quick research, this model is running at 100Hz. I've seen and tested a 29" Thomson set in person before and found it to be quite blurry. It became even more evident as there was an option on the remote to freeze the frame on this particular TV and you could immediately see that the 100Hz processing was introducing the blurring as the frozen frame was very sharp.

My question is : Anyone in here know how to bypass the 100Hz on these sets and get the 'original' picture on these Thomson TVs and chassis? Any tip or advice would be appreciated!

[matt]

I doubt it. 100hz TVs are locked at 31khz horizontal, so without the frame doubling you couldn't display an SD signal.

IIRC some of these TVs can be modded to accept VGA though.

[SCARTicus]

I don't know how you can stand to look at 50Hz. I've had a few multi-format televisions and experimented with PAL50. So much flicker. It hurt my head to look at video or games like that. I was amazed at the difference between 50Hz and 60Hz. This has got to be why we never saw 120Hz CRT televisions in the US. You poor Euros. But, hey, at least your not in SECAM land!

[mutmut02]

@Matt : Thanks for your answer. It's a shame really : a 37" RGB CRT that cannot be used for games make me sad. I wish I had more space but I guess I'll just have to forget about it ...

[Syntax]

Try feeding it a 31k image, it may bypass the scaler and look decent/ less lag

[strayan]

Try feeding it a 31k image, it may bypass the scaler and look decent/ less lag

Yeah, that’s exactly what happens with my 100Hz Philips CRT. 31khz signal bypass the scaler.

[SuperSpongo]

Really? Do you know the Philips model, by any chance?

Normally, the TV has to have a dedicated signal path to run progressive signals. Otherwise, the image goes down the same processing path as a 15kHz signal and the result is a split image, only displayed in 120Hz as opposed to 60

The TVs I've seen that officially support progressive YPbPr or VGA like Metz or Grundig TVs have a dedicated VGA input card or (in case of the Metz) have to be set to progressive via the OSD.

[strayan]

Really? Do you know the Philips model, by any chance?

http://www.avbuzz.com/PhilipsPixelPlus2 ... lus29P.htm

[SuperSpongo]

Really cool, thanks! Looks like we did not get this model here in Europe.

[mutmut02]

Try feeding it a 31k image, it may bypass the scaler and look decent/ less lag

Thanks for the advice. How would you recommand to try it first ? Feeding 31Khz picture through the scart RGB input ? RGBs or RGBHV ?

I found this detailed info on the ICC19 Chassis if it's of any help :

https://www.manualslib.com/manual/16569 ... tml#manual

[SuperSpongo]

Page 86: 50Hz set uses IV001, 100Hz set uses IV601

"RGB and FB signals from SCART connector AV1 are sent to:
• The video processor, IV001, for a 50-Hz television set.
• The demodulator, IV601, for a 100-Hz television set"

Page 103, 104: 100-Hz VIDEOPROCESSING

IV601 takes RGB, S-Video and Composite signals and converts them to YUV plus Horizontal and Vertical Sync. After that, the next Chip IV308 does the framedoubling, using IV309 frame memory. The YUV signal is eventually converted back to RGB and output. The Thomson explanation is on page 105 ff.

[mutmut02]

Thanks for the pointerr. So bypassing IV601 seems to be the correct way. Dunno if I can do it but I'll probably give a shot once I've figured how to store this.