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Component modding CRT TV
Zebidee:
Thanks!
You should do your own research first. Identify model number and chassis number if possible. Identify the jungle IC number and where the inputs are. You should do an online search for datasheets on your jungle IC and schematics. Sometimes you can't find the exact datasheet or schematic for your TV, but one for something close can often suffice.
If you can do an RGB mod, then you are probably better off doing that. Unfortunately you can't do that with all TVs.
YPbPr/component input is almost as good as RGB if you are using the latest GreenAntz RGB to Component Transcoder v1.94. GreenAntz gives much better image quality than the cheap transcoders on Aliexpress (which are actually a substandard ripoff of a leaked old pre-GreenAntz design), which have washed-out color and "flickeryness".
These "China TV" chassis I'm working on are available new, also on Aliexpress, from around $25 each. They will work with most standard 14"-21" CRTs. They give better performance than most cheap arcade monitor RGB chassis that I've used. I've worked on them a lot and gotten to know them pretty well, so can perform most tweaking and repairs myself.
--- Quote from: delta88 on March 06, 2025, 09:32:52 pm ---This is brilliant! I have some tvs from the 90s that ive been hoarding with hopes of pulling the case to see if they are candidates for chassis swap for some of my games. shooting from the hip what would you say my odds are of doing something like this to say a 90s zenith , rca?
--- End quote ---
Zebidee:
I noticed a lot of "bleeding" on blue with these last two modded TVs. After investigating many dead ends, I found the solution on the neckboards.
For some reason their neckboards have a 471 (470pF) capacitor (circled in yellow) on the blue drive transistor instead of a 391 (390pF). My earlier modded TVs have a 391 there, and they didn't have the bleeding issue. Don't understand why they used a 471, maybe it looks better that way with TV/composite video input. Looks pretty crap with component input.
Anyway, I swapped out the 471 for a 391 and the picture improved significantly, much sharper and less bleeding :cheers: I also found a burnt-out resistor (33R) on one, and replaced it with the blue one there (30R, circled in purple). That resistor connects G1 and G2. 30R was the closest value I had available, it seems to be holding up fine.
I'll improve the picture a bit more again by tweaking the service menu. More on that soon.
Zebidee:
Uploading some info: datasheets, schematics, service mode.
None of this is 100% match for these TVs, but is close enough.
To access service mode:
- press MENU
- press 2,4,8,3 - the word "FACTORY" should appear.
- press DISP
This gets you to page 0, "white balance", of the service menu. Press number keys to change page. To go above page 3, find "PAGE" and flip the value to "1". Press MUTE to go up one page. AFAIK this is the only way to access pages above 9.
Zebidee:
More China TV datasheet/schematics/service mode info that would not fit in last post. Attached as a zip file.
dennisbgi7:
Firstly, amazing idea and amazing execution, this is fantastic. I did have a question, more of a noob question since I am new to all this.....what did you do about the audio? I understand the side port now takes in component video signals, but since the composite audio is being replaced in this case, what are you doing about that? Also, is the composite input at the back still usable after this?
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