Main > Monitor/Video Forum
Component modding CRT TV - "China TV"
Zebidee:
A quick search online reveals many Philips CRTs allowed service mode access via entering a specific sequence of numbers, then pressing menu or info.
" 0 6 2 5 9 6" then "Menu" or "info" or "Exit". You might need an original remote.
I got a bunch of hits when I searched for "service mode philips tv crt".
This seems consistent with the last time I modded a Philips TV, but that was a long time ago. Seems to be the same or similar for most Philips models. I don't know if there are some TCL codes that override that.
Razmann4k:
Yes, I also tested this sequence, and it didn't work. I even tried the TCL ones where it tells you to go into the settings, select contrast then type 1950 and other numbers. They didn't seem to work.
I was just wondering, when a TV is a rebrand, does the logo on the front even matter? Should I not just treat it as a TCL? Or would Philips have changed the code? It's a shame I can't easily find documentation on this specific TV. If I could find its TCL cousin then perhaps its manual would apply here.
Zebidee:
--- Quote from: Razmann4k on March 06, 2026, 06:17:02 am ---Yes, I also tested this sequence, and it didn't work. I even tried the TCL ones where it tells you to go into the settings, select contrast then type 1950 and other numbers. They didn't seem to work.
--- End quote ---
Worked for me with the TCL I modded last year. However, that may be a completely different jungle IC (Trident TDA11135PS/N3/3).
--- Quote ---I was just wondering, when a TV is a rebrand, does the logo on the front even matter? Should I not just treat it as a TCL? Or would Philips have changed the code? It's a shame I can't easily find documentation on this specific TV. If I could find its TCL cousin then perhaps its manual would apply here.
--- End quote ---
Yeah, the logo on the front may matter little. For my TCL TV I replaced the jungle IC with a NOS one (from ebay or aliexpress, can't recall now) that came from a ROWA branded TV and that logo is "baked" into the jungle itself, not the EEPROM. So the ROWA Logo comes up when there is no other input. Aside from the "collars and cuffs" not matching, it works just as well, and I follow the jungle IC datasheet itself.
AFAIK TCL didn't make jungle ICs for CRTs themselves. But they are a big Chinese manufacturer in an industry with many moving parts, I don't know for sure. By the 2000's all TV manufacturers were buying parts from other players, including their "competitors", on the OEM markets. There were only a handful of jungle IC manufacturers, whichever made the best and cheapest survived. Rampant free market capitalism in a fully globalised economy, yay.
So, I'd be interested if even the jungle IC has been "rebranded" from a company like Trident or Toshiba. Got a good closeup photo?
This is a good video of accessing service mode for a 2000's era Philips CRT. There are some fussy things to do. Worth a watch.
Razmann4k:
Thanks for the help, very luckily I managed to figure it out!
This TV is 100% TCL, it doesn't have a bootup logo (no cuffs and collars to speak of :D) but the only thing that's Philips about it is the plastic logo on the front.
Turns out I was being a bit dumb, the Jungle IC is a 8821CRNG5HG4, the TCL-A30V01-TO was the first thing I spotted, but I should've noted the number below it instead.
Either way, I found the service manual for a similar but not identical TCL TV and it told me to turn the volume down to 0 and hold vol. down on the TV while pressing display on the remote and that worked!
Unfortunately this is where I ran into yet another problem. While the service manual on my China CRT was relatively simple to understand and navigate (just had to change pages until I found Enable YUV and set that from 0 to 1), this TCL was indecipherable with no YUV, DVD or S-Video enable anywhere. However, thanks to the manual from a similar TV I found earlier I was able to understand that this TV doesn't have enable flags exposed directly, it's a little more obfuscated, under the MODE1 setting it shows in the service manual YUV as bit 6, and that MODE1 is a bitwise map that contains a 8 bits total, and you need to enable the correct bit (flip that from 0 to 1) to enable what you want. So I had to flip bit 6 from 0 to 1. However it's not stored in simple binary, its a HEX value, so I had to convert the currently stored value (97) from HEX (0x97) to binary ()
MODE1 is an 8-bit register. Each feature is controlled by a specific bit. The value you see (like F0, FC, etc.) is the sum of all active bits.
Bit Values
Bit Feature Hex Value Binary
0 BG System enable 0x01 00000001
1 I system enable 0x02 00000010
2 DK system enable 0x04 00000100
3 M system enable 0x08 00001000
4 VIDEO2 enable 0x10 00010000
5 VIDEO3 enable 0x20 00100000
6 YUV enable 0x40 01000000
7 Thailand Dual language 0x80 10000000
Current: 10010111 (0x97)
Add YUV bit 6: 01000000 (0x40)
New binary: 11010111 = 0xD7
So I changed MODE1 from 97 to D7 and the component input appeared on the TV at last!
However, I then had another problem... it wasn't working. On the hardware side I thought I was lucky because I found pads labelled Y Cb and Cr on the board right next to the composite ports, so I soldered onto those thinking that perhaps the manufacturer simply left the component ports out. Turns out I was wrong.
I thought maybe there's just some pulldown resistors but trying to follow them back to the jungle chip was a nightmare, they had caps and resistors and jumpers all over the place. I knew pins 19 - 21 were the correct ones, so I decided to just cut those pins off the board to completely isolate them from the mess of traces below and bend them up at a 90 degree angle to solder onto them directly. I used hot glue afterwards to secure the delicate wires and pins and did something I'm not entirely proud of...
I took apart my 14" China CRT and pilfered the PCB I made for it last year because it was late at night and I didn't want to have to make another one. (I'll make another one for that TV so it doesn't become a composite only paperweight again) I soldered the PCB onto the new TV and it works!
It seems the colour maths are correct for this TV too. The PCB worked great in the 14" but it was designed for what that TV's schematics require, not this 21" TCL. It has 75 ohm termination, 75 ohms in series with each of them and 1uF electrolytic for the Y, and 104s for the Pb and Pr.
The OSD is pin sharp, but both composite and the newly-added component look similarly soft. The TV has a sharpness control (0-100) that at 50 adds obvious haloing. At 0 it looks soft, and 25-30 seems a reasonable compromise—but I can't tell if that's because 0 reveals the TV's natural softness, or if 0 is actually applying some sort of anti-sharpening filter. Any thoughts?
Zebidee:
:pics
Yeah, a Toshiba jungle! That other number didn't make sense.
Well done for working it out, and thanks for stepping through it and explaining everything! Useful insights into how the service mode works. And adding bits in hex! For some models it can be very opaque.
Sharpness... mostly I find setting it to zero is best, but sometimes you need a little. There may be more than one sharpness setting.
For pure RGB input you mostly shouldn't need it, aside from compensating for the CRT itself (shadow mask/phosphor alignment or whatever). For component input there will be video processing errors and timing mismatching as the jungle must convert the video and colour signal from YPbPr to YUV to RGB for the CRT cathode ray guns.
For the jungle, Y is simple to process as it is essentially just black & white video. However the UV (colour information) takes a little longer to process as it must be demodulated (up to a few hundreds of nanoseconds) and mixed back with Y to produce RGB. This delay can be visible as a slight alignment mismatch between changes in luma (brightness/green) and certain colours. Very difficult to see with normal video content, but more apparent in computer games that have hard lines, and some sharp changes of solid colours.
You can play around with different service mode settings like Y-delay, color modes, tone and even sharpness to either correct or obfuscate these errors.
A cheap 2000's TV that looks OK with composite input might need some tweaking to look good with component input. They were being made cheap then so nobody was wasting time in the factory to make them look perfect.
You can improve the image sharpness a lot by simply getting the colour gain and cutoffs right, to maximise intensity while minimising bleed.
You can also play with using a 1uf (vs 0.1uf) on Y input. With 1uf the Y signal persists a little longer, makes it a tiny bit fuzzier. Even 10uf would probably not be terrible. I dunno, depends on the TV and personal choice. Compromise.
Try 100R for the inline resistors.
Sometimes I even go extreme and change other components on the TV, such as certain capacitors on the blue drive transistors (on the neckboard).
--- Quote ---On the hardware side I thought I was lucky because I found pads labelled Y Cb and Cr on the board right next to the composite ports, so I soldered onto those thinking that perhaps the manufacturer simply left the component ports out. Turns out I was wrong.
--- End quote ---
Yeah, you can't assume anything. Even if the PCB traces are still there, you'd need to add some components like the inline caps & resistors; & terminator resistors.
Plot it out with a multimeter. Whether the PCB traces are there or not, you may find the Y Cb Cr inputs (maybe just the Cb,Cr) connected to ground via one or more 103 capacitors (prevents unused inputs from floating). You should remove the 103s and maybe use the vacated footprint as an easier place to land your inputs.
Pics please!
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version