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CTC169

First off, let me say that I'm not a TV tech.... I'm an elec. eng. who
does controls for a living.

Anyhow, I got this dead RCA set for free and am working on it for fun
and to learn.

The TV: RCA colortrack 2000 invar CHASIS CTC169


The set was initially dead. After reading through many postings in
this group... I have done the following troubleshooting and replaced
the following components.

Failed components found:

blown 5A inline fuse
Open flame proof resistor 2.5 ohm (if i remember correctly)
Shorted B+ regulator


Components replaced: (based on my internet reading)

Above mentioned parts plus....

CR4118
U4101
C4102
C4104
C4108


The set is no longer dead but presents some odd symptoms. The set
powers up.... audio is fine. The first thing I see is a horizontal
green line across the screen which is shortly replaced by a picture.
The picture and menus are darker then they should be and are
vertically stretched. If I do an autoprogram (channel search), the
picture will return to a normal size, but will remain on the dark side
with the menus showing up in dark blue which is barely visible. Once,
the set is powered down and back up, the picture is once again
vertically stretched and cured by autoprogram.

I've measured the cathode voltages of CR4118 & CR4116 to the ground
around the picture tube. The voltage readings are 12.47 and 135
respectively Based on my reading, these sound a bit low, but I'm not
sure where to go from here. I have followed the ground path around
the board and cleaned up some solder joints, but the symptoms
persist. Any thoughts?

Thanks
Bob
 
N

NeverExpectPowerAlways

Jan 1, 1970
0
First off, let me say that I'm not a TV tech.... I'm an elec. eng. who
does controls for a living.

Anyhow, I got this dead RCA set for free and am working on it for fun
and to learn.

The TV: RCA colortrack 2000 invar CHASIS CTC169


The set was initially dead. After reading through many postings in
this group... I have done the following troubleshooting and replaced
the following components.

Failed components found:

blown 5A inline fuse
Open flame proof resistor 2.5 ohm (if i remember correctly)
Shorted B+ regulator


Components replaced: (based on my internet reading)

Above mentioned parts plus....

CR4118
U4101
C4102
C4104
C4108


The set is no longer dead but presents some odd symptoms. The set
powers up.... audio is fine. The first thing I see is a horizontal
green line across the screen which is shortly replaced by a picture.
The picture and menus are darker then they should be and are
vertically stretched. If I do an autoprogram (channel search), the
picture will return to a normal size, but will remain on the dark side
with the menus showing up in dark blue which is barely visible. Once,
the set is powered down and back up, the picture is once again
vertically stretched and cured by autoprogram.

I've measured the cathode voltages of CR4118 & CR4116 to the ground
around the picture tube. The voltage readings are 12.47 and 135
respectively Based on my reading, these sound a bit low, but I'm not
sure where to go from here. I have followed the ground path around
the board and cleaned up some solder joints, but the symptoms
persist. Any thoughts?

Thanks
Bob

Bob, I have even less qualifications than you to open up a TV set, but I
just finished fixing the remote receiving unit on a 1987 Mitsubishi set.
In the course of the repair I discovered two switches on the printed
circuit board mounted on the end of the cathode ray tube. They are both
three-position switches and while manipulating the main circuit board
with all its wiring I managed to move one of them to the wrong position.

I ended up with a single horizontal line across the middle of the tube.
After resetting it and getting back the whole picture, I flipped them
both all three ways to see what happens. The color changed as if the
blue or red had been lost. So I flipped them back to where everything
was good. This may or may not have anything to do with your problem, but
you may find this site helpful. It's where I learned about those
switches and where they are located:

Sci.Electronics.Repair FAQ: Main Table of Contents
http://www.repairfaq.org/REPAIR/F_Repair.html

Scroll down to where it reads:

Television Sets (new segmented, includes download link) | (latest whole
- slow)

Lots of great troubleshooting info there.

Good luck,
Jack
 

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