TV Forums

Free Games TV Forums

  Main Index FORUM
HOME 		Search Posts SEARCH
POSTS 		Who's Online WHO'S
ONLINE 		Log in LOG
IN 		Rules & FAQ RULES
F.A.Q.

Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Zenith TV gives cyan instead of green.

 
 


gsmollin
New User

Jul 27, 2004, 4:23 PM

Post #1 of 3 (1248 views)
Shortcut
Zenith TV gives cyan instead of green. Can't Post
Set model: Zenith 27" SMS7767S9, module: 9-1408, DOM: October, 1994
Symptoms: The picture is too blue. Color bars show cyan where there should be pure green. Blue and red appear normal.
Other info: This set uses a Santo LA7672 IF/video processor.
Question: What has failed?

Thank you for your response.



mel
Veteran

Jul 28, 2004, 12:49 AM

Post #2 of 3 (1241 views)
Shortcut
Re: [gsmollin] Zenith TV gives cyan instead of green. [In reply to] Can't Post
Bad news. Mid to late 90s Zeniths are infamous for bad picture tubes. Even if your current problem is not the Picture tube, and only a qualified tech with proper test equipment can tell for sure, you would probably be better off to invest in a new set than to spend any money on a set which will probably not last a whole lot longer without other major repairs.


gsmollin
New User

Jul 28, 2004, 1:04 PM

Post #3 of 3 (1238 views)
Shortcut
Re: [mel] Zenith TV gives cyan instead of green. [In reply to] Can't Post
The problem is a weak green gun in the CRT. The tint circuit was compensating, and at the end of its range it turned-on the blue gun. I re-biased the blue and green guns to boost the green gun current and slightly reduce the blue gun current. Red was good. The picture now looks pretty good. Of course, I'm no longer following the NTSC color mixing laws, so the chroma shows exaggerated sensitivity to y channel, with dark scenes being bluish, and bright scenes looking correct. I think that's good enough, since dark scenes tend to be bluish anyway. At any rate, that's all that picture tube has left to give after 10 years, so I'll take it and retire the set when the green gun wears out.

Thanks for your help.

 
 
 


Search for (options) - Page loaded in: 0.22 s on (CGI/1.1)