The means colors that are not normal and that adjustment of the user
controls is not able to correct it so that all colors of the picture
are properly displayed at the same time. For example, you are unable
to get any yellows or blues in scenes that should have these colors..
|NotTaR of Television Sets : Psychodelic color
1994-2007, Samuel M. Goldwasser. All Rights Reserved. Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied: 1. This notice is included in its entirety at the beginning. 2. There is no charge except to cover the costs of copying.
I may be contacted via the Sci.Electronics.Repair FAQ (www.repairfaq.org) Email Links Page.
<< One color is too weak or .. |
| No picture/dark picture/e.. >>
Make sure the user color and tint controls have not been accidentally
turned while cleaning or purposedly misadjusted by small (or large) kids.
Perform the user setup described in the section: User
Confirm that the source is not a weird color video - try another
channel or a tape.
Verify that this is not a missing color problem - one of the primary R, G,
or B, has disappeared. If so, refer to the section:
Intermittent or missing colors.
Once these have been eliminated, you are left with the
- Defective part around the chroma chip/circuit. Misadjusted color
- Bad connections or short circuit in area of chroma chip/circuit.
- Defective chroma chip (don't suspect this first just because it
is probably very expensive).
- Bad degauss circuit resulting in lack of degauss or abrupt termination
of degauss current rather than smooth tail off. The CRT is not being
properly demagnetized and color purity is totally messed up.
- Bad CRT - the shadow mask has been damaged and it is impossible to
properly adjust purity across the screen.
A service manual or Sams', DMM, and scope will help greatly in attempting to
troubleshoot this unless it is an obvious bad connection. For (1)-(3),
try prodding the main board around the chroma chip with an insulated tool
to see if you can restore normal color. For (4) try manually degaussing
(see the section: Degaussing (demagnetizing) a CRT.
If this clears up the colors until at least when it is power cycled, then a
degauss problem is likely.
Something as simple as a bad resistor or inductor can be the cause - don't
immediately suspect the most expensive and difficult to replace part.
<<One color is too weak or .. |
| No picture/dark picture/e..>>