[TechAssist] Re: RCA PTK178, Close captioning question.

VITS was setup so that broadcasters could monitor their signal levels. 
There is a full set of standard test signals in the VI. Using a special 
scope made  by Techtronics, you can check Y levels, chrom levels and 
phase and also display it on a vector scope.
It is a question that manufacturers didn't pick up on this to use as an 
auto colour/brightness control.

Al G
Al's TV-Electronics
Pembroke Ont.
Canada

Hoyt's TV wrote:

> VITS = vertical interval test signal
> 
> If you can roll the picture down so you can see the blanking bar, you may
> see some dashes in there. Dats it.
> It contains all the information needed to automatically adjust the
> brightness, contrast, color and tint, using a special circuit that can be
> built into the TV. The only TVs I ever came across with the circuitry in
> them, were a few GEs about 25 years ago. It was supposed to be the greatest
> thing since sliced bread, but no one bothered with it.
> 
> 
> Russ Hoyt
> Hoyt's TV
> Exeter, NH
> 
> 
> ----- Original Message ----- 
> From: "Kevin" <kevintv@xxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Friday, December 31, 2004 3:27 PM
> Subject: [TechAssist] Re: RCA PTK178, Close captioning question.
> 
> 
> 
>>What is VITS?  18 years ago TSN (The Sports Network) was always washed
>>out looking on the first 40" Mitsubishi projection TV's.  I think my
>>boss phoned the cable company and they said they could do nothing about
>>it because it was the fault of the channel.  8 years later I bought a
>>used Panasonic GAOO 27" and it had the same problem with TSN.  I phoned
>>the cable company and it was fixed the very next day.  The cable must
>>have been doing similar things with the video signal.
>>
>>Kevin Wilks
>>Kevin's TV & Video Repair
>>Penticton BC Canada
>>kevintv@xxxxxxx
>>
>>
>>-----Original Message-----
>>From: techassist-bounce@xxxxxxxxxxxxx
>>[mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of Hoyt's TV
>>Sent: Friday, December 31, 2004 5:43 AM
>>To: techassist@xxxxxxxxxxxxx
>>Subject: [TechAssist] Re: RCA PTK178, Close captioning question.
>>
>>Since no one else has jumped in, I'll give you my 2 cents worth.
>>
>>I haven't studied that situation, but it sounds likely to me. I believe
>>(really taxing the memory here) that CC is in the vertical interval and
>>whenever the composite signal is disassembled and reassembled, as some
>>cable
>>companies have done in the past, it's easy to lose some of those things.
>>Any
>>time you use a set top box, you have the chance that this was done to
>>the
>>signal at some point, because somebody has had the opportunity to mess
>>with
>>that signal after it left the transmitter and before it got to you. Not
>>all
>>of them are broadcast engineers.
>>
>>Around here we had a problem 25 years ago of severe brightness
>>differences
>>between channels on Zenith TVs of the vertical chassis design, but only
>>on
>>cable. Seems that Zenith was using the base line in the video signal as
>>an
>>automatic brightness reference. Our cable company was disassembling and
>>reassembling each channel before putting it on their system and not
>>paying
>>much attention to that part of the signal. It only bothered Zeniths, so
>>apparently they were the only company using that as a brightness
>>reference.
>>
>>The cable company denied it of course, but Zenith's engineers explained
>>it
>>to me in great detail. Since they were the ones who originally designed
>>the
>>cable system we use, way back in the late 40s and early 50s. Since the
>>guy I
>>talked to was there at the time, I kind of believed him over the cable
>>company.
>>
>>What ever happened to VITS? I saw a few GE TVs that used it, way back
>>when.
>>Never saw any others.
>>
>>
>>Russ Hoyt
>>Hoyt's TV
>>Exeter, NH
>>
>>
>>----- Original Message ----- 
>>From: "Kevin" <kevintv@xxxxxxx>
>>To: "TECH-ASSIST" <techassist@xxxxxxxxxxxxx>
>>Sent: Thursday, December 30, 2004 4:14 PM
>>Subject: [TechAssist] RCA PTK178, Close captioning question.
>>
>>
>>
>>>Sorry I do not have the model #, but this is just a general question
>>>about CC, so I hope that will be OK.  Does CC work through all inputs
>>>(cable, composite, S-Video, and component)?  Or does CC only work
>>>through channel 3?  I repaired an RCA PTK178 and hooked up their
>>>satellite through the S-Video input, and disconnected the cable from
>>
>>the
>>
>>>satellite receiver.  Now they say the CC is turned on but does not
>>
>>work
>>
>>>at all.  I suggested they watch the satellite through channel 3 as
>>
>>they
>>
>>>did before the repair and see if that corrects the problem.  By the
>>
>>way
>>
>>>the original problem was coolant on the P/S board that was causing a
>>>jitter in the picture.  I repaired it by cleaning the board, replacing
>>
>>a
>>
>>>cap, and resealing all 3 tubes.
>>>
>>>Kevin Wilks
>>>Kevin's TV & Video Repair
>>>Penticton BC Canada
>>>kevintv@xxxxxxx
>>>
>>>
>>>
>>>
>>>
>>
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