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CRT TV: More Colors, Only B&W

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Evirame77 Posted messages 2 Status Member -  
Andy31200 Posted messages 26918 Registration date   Status Moderator Last intervention   -
Hello everyone! A friend entrusted me with her THOMSON C36CN62 TV to repair, as it wouldn't turn on. The 1.6A fuse blew, and the 2SD898 transistor was shorted. I ordered the transistor and the flyback transformer, then replaced everything.
The TV turned on properly; I adjusted the G2 and focus on the flyback transformer to get a correct image.
I tested this analog TV with a TNT decoder that I use every day: the image is in black and white, while the color is fine on the TV I usually use. The SCART cable is the one used for the usual TV, no loose connections. No dry solder joints are visible on the Thomson TV board either. The black and white is clean, with no signs of color appearing or indications of a loose connection... For precision, the color adjustment potentiometer is completely inactive. However, the three adjustments R, G, and B do enhance their respective colors and balance the three colors to achieve a correct white...
Can anyone give me a lead? Does anyone have the schematic for this set, as it seems like the color adjustment potentiometer has no effect anymore...?

Thanks in advance,
JB

4 answers

  1.
    Andy31200 Posted messages 26918 Registration date   Status Moderator Last intervention   12 207
     
    Hello,
    Is your SCART connector with all the contacts (RGB)?
    Would this TV only be SECAM?
    Otherwise, good luck...

    --
    I call a spade a spade...
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  2. Evirame77
     
    Hi Andy, and thanks for your reply.... This TV has always worked in color from the SCART, until the THT failure.... I know this TV inside out, it's my old one.... Well, my ex's!

    As for the SCART cable being used, it's the one I use every day to watch the DTT in the bedroom on my CRT TV. When connected to the bedroom TV, it works; connected to the faulty TV, it's just in black and white.... Something doesn’t add up....
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    1. pacalvideo Posted messages 3358 Status Member 396
       
      unless I'm mistaken, your HT must be at 25Kw to have the color (the N.B is 15Kw)
      (source given by a colleague technician) if of course your TV is multi-standard (PAL SECAM)
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    2. Andy31200 Posted messages 26918 Registration date   Status Moderator Last intervention   12 207
       
      And watch where you put your hands, discharge the capacitors first, otherwise the 25 kW will hurt...
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  3. Anonymous user
     
    uh ................ most TNT receivers output a composite video in PAL, so you'll get a B/W image on the TV which is likely just SECAM!!!

    so check the receiver options to see if you have the SECAM choice, if not switch to component (RGB) and it should be fine
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  4. Evirame77 Posted messages 2 Status Member
     
    Big shout out for this post since it's been a while since I solved this issue!

    Andy31200 was right, the SCART cable didn't have the RGB connections and I got caught out on that point......

    With a "complete" SCART cable, everything works now with very beautiful colors. It's an opportunity to see that a good CRT is much more "refined" in grain than an average LCD..... The HD looks extremely good....

    Thank you all!
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    1. Andy31200 Posted messages 26918 Registration date   Status Moderator Last intervention   12 207
       
      But you're welcome and thank you for coming back and marking it as resolved.
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