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Component modding CRT TV - "China TV"

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Razmann4k:
Thanks for all the info on component colour and resistor values! I'll be performing a lot of testing to get it right.

I noticed the image is a rotated to the left by a few degrees and the convergence is out a little in the top left and bottom right corners too.
The upside though with this TV is that blooming is far less noticeable than on my 14" CRT, and scanlines are finally visible.

The way I have it atm, with sharpness at 0 it looks awful, like vaseline was smeared all over the screen, even relatively large text is noticeably blurry. The OSD is pin sharp however, like I said. My old Sonistar was pin sharp everywhere with the same PCB, so perhaps this TV is expecting a different set of values like you said.

Pictures you requested, and pictures you shall get:
Description of each picture in order:
1. A collage of all the service menu pages I could get to display (0 - 9 buttons and calendar, so 10 pages total). There may be more but I'm not sure. Strangely this TV displays some different items when displaying NTSC and PAL, with PAL being the default (all of these are for PAL, most should apply to both apart from the geometry ones)
2. The jungle IC of the 21" Philips, it may be hard to see but it says 8821CRNG5HG4.
3. The underside of the board, with the jungle being IC201 on the right. You can also see the pads for the RCA connectors on the left, Vin, Lin and Rin for the standard composite input, Vo, Lo and Ro for composite out, and Y, Cb and Cr right next to composite out. You'll notice I bridged the component pins to Vo, that's so I can utilise its RCAs. I naturally removed the resistors that connect the composite out pads to the rest of the board. Once I realised the Y, Cb and Cr pads weren't ready to work out of the box I removed this bridge and soldered directly to the back of the RCAs on top, which of course have continuity with Vo, Lo and Ro. You'll also notice Y and C below that, this TV could've also had S-video.
4. The PCB I made last year being stripped out of my 14" Sonistar. I don't have a picture of the completed install in the Philips but will once I open it again. As you can see it has a 1uF electrolytic for Y, 104s for Pb and Pr. 75 ohm termination and 75 ohm inline. This worked great in the Sonistar but maybe not so great in the Philips. I'll make a duplicate of this board and solder it back into the Sonistar, or perhaps if I can figure out the mainboard's traces I could just put it straight back into the Sonistar instead.

Zebidee:
Looking good!



--- Quote ---I noticed the image is a rotated to the left by a few degrees and the convergence is out a little in the top left and bottom right corners too.
The upside though with this TV is that blooming is far less noticeable than on my 14" CRT, and scanlines are finally visible.

--- End quote ---


The image rotation would be a yoke alignment thing. To fix that you'd need to loosen the yoke (there will be one (or maybe two) ring clamp, and you'd need to loosen some rubber wedges) and twist it slightly while the TV is powered on and displaying a test image.

If you use silicon to re-glue the rubber wedges be sure to leave the back off about 24 hours, and be careful what you touch with dirty fingers - for some silicons, as it cures it releases a vapour that can corrode copper. You could use hot glue instead but I never trust that very much.

For your mini-PCB, try putting the inline capacitors *after* the inline resistors. And try using 100R there instead, as suggested earlier.

Of course, those Ro and Lo connection points are for right/left audio, so I assume you've cut some traces if repurposing them for Pr/Pb. In addition, on most (all?) of these 2000s cheap China TV variants they would run the right and left audio channels together (connection deliberately bridged with copper trace). On some of my China TVs the L/R channels were connected on the side input, so you'll need to check everywhere.

Try playing with that HDDELAY setting, I'm wondering if it is something similar to the Y-delay I was talking about earlier.

Good luck!

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