I have a 27" Toshiba Cinema Series tv set I've been working on, the problem is a dark picture, the High Voltage is where it should be and it appears to have plenty of Screen Voltage Range, I suspected a video problem, and replaced the Video Detector IC with no luck, at this point I have no idea where to look next, any ideas?
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
There are two small holes on the rear side through which you can adjust focus and screen. Use a flash light and locate the two adjustable slots inside the holes. This part carries high voltage. Do not use a metal screwdriver to adjust. Put the TV facing a mirror so you can see how it works. Do not turn more than 1/8th of a turn. The focus control makes picture sharp or fuzzy. Screen control could change brightness. While watching the picture in the mirror, slightly adjust the screen control. Do not turn too much. If it doesn't work, then call a JVC authorized repair center.
Dark picture? hmm. meaning there is no brightness variation, assuming this is the fault I think U might be having low screen voltage. Check for high value ( around 2W) resistor, preferably from 100K to 680K on the "C" board or neck board. Post back Rifaa
Adjustable Color Temp.
The Adjustable Color Temperature feature lets you adjust the color balance on your TV, depending on the type of light in the room, such as direct sunlight or artificial lighting.
On your remote control there should be a button that lets you change the picture mode, IE. Rich, Personnal, Cinema, Sport etc...
I likely you have a loose conection in the crt board at the neck of the picture tube or a loose conection close to the high voltage transformer,I would suggest to tap the main board as well as the crt board with a wooden or rubber handle(not metal),be attentive were you tap to see if the set reacts ,if the set reacts you will need to resolder those places ,be carefull working on a set that is on while you do it,this should give some idea what the problem could be in case you want to call someone to help you with the repair.Let Us know if you need more information.
zenith have many problems with crt (picture tube) they comes be short or one or more canon fail, there are nothing to do, replace the picture tube, and thats a lot of money for an old tv...good luck
ps adjusting the screen and resoldering the picture tube card could help but remember there are many dangerous circuit in a tv...
this problem is due to
1 not proper voltage on crt terminals
2 check video output supply voltage
3 check luminance section of chroma ic
4 if tv is very very old than there is a possibility of crt getting weak
If the picture is fading slowly out it could just be a cold solder connection on the ctr board or the Hi voltage circuit that supplys the filiment voltage to the crt. To check this you have the back off and when the pic goes out you look at the crt to see if its still lighting up. if its not then you gotta find out where your missing the filiment voltage at> If there is still a light inside the tube when the picture is dark then it could be a PIP problem or in the video section /video jungle IC on the set. Now these sets have alot of high voltage inside them even when the sets unplugged so I advise against going inside and tweeking with the set unless you know all the safty issues with the Hi voltage and storage capacitors inside this set. there are no real user serviceable parts inside these sets and should only be serviced by a quilified service person. Good Luck