RCA CTC 203 sound

Many threads about this recently. There is no real fix, but a workarouns is a cap from a pin of the micro to somewhere else, maybe round. Look it up. The cap will also disable CC, so it's not a completely perfect fix.

If you don't have the same source, and tune to the same channels, you may not be able to duplicate the problem. Even if you do you may not get the same signal condition that triggers the problem.

Do some searching. There is much discussion on this matter and patches. You might get on some of the many tech forums where techs share advice and fixes. You can find lots of this info in the archives of this group with a Google search. There is also an article in "The Speaker", a newsletter published online by NESDA Ohio and can be accessed by simply signing up at their site. There are many useful articles there.

Some places that you might look to for resources for service techs are below. There are many more.

Hi. For what it is worth, something I have learned about this problem, as I have one to play with. I have found a workaround that works like a champ, provided you have the A/V jacks on back and either a vcr, digital cable or sat box. Take the output from your box of choice and connect to A/V jacks. Then switch to A/V input with remote. The sound problem doesn't seem to affect these jacks, and you get a sharper picture to boot.

I tried disconnecting the GEM module, which seemed to do the trick, but in reality it didn't, as I had unplugged set to try the idea out.

I will see how the A/V bypass does, but no complaint so far. I know it isn't a fix, but it was the only option available to me, see below.

I know it is some signal sent from the broadcaster, with 2 too many bits, or some such, that overloads a buffer. I had considered doing the cap bypass but couldn't, as the owner is 85 years old, has 2 hearing aids, and deinitely uses closed caption.

Danny

RCA CTC195, CTC197, CTC203 Audio-Dropout "Glitch"

THOMSON AUDIO DROP-OUT

There has been a situation when in some RCA/GE televisions a low-level, scratchy-sounding noise comes out of the speakers instead of normal audio, or when video is muted. These problems can occur when invalid XDS data is broadcast by television stations and received by certain Thomson television receivers. XDS data is digital information placed within the video signal's vertical interval of an analog (NTSC) television transmission. This data is used by the microprocessor in the television receiver. It may be transmitted from any analog television channel.

Explanation of XDS data: In each frame of video, line 21 contains a single stream of data, containing different types of data packets. Field 1 of line 21 contains two captioning channels (CC1 and CC2) and two "text" channels (TEXT1 and TEXT2). All four of these data channels share that 600 cps data stream, and the information is sorted out using packet headers. Field 2 contains a matching set of data channels (CC3, CC4, TEXT3, and TEXT4), and can also contain extended data services (XDS) packets.

The XDS (extended data services) provide information about the current

program, TV station, and network. Unlike the caption and text data, they are packets rather than continuous streams of data.

XDS packets include:

Name, length, and start time of current show Type of show, based on a set of category codes Program content advisory (see "V-chip data" below) Network name Station name and number Time of day National weather service warning codes.

The "Thomson audio drop-out problem" occurs when a broadcaster sends invalid XDS data - that is, data that does not contain truncation packets. There are certain XDS encoders on the market that broadcasters may use that will do this. Thomson television receivers using 16-bit microprocessors (i.e. CTC197/PTK195 chassis) are programmed to decode XDS data by counting data packets. When the microprocessor encounters corrupt data with no truncation packets, the data overflows into memory registers where it does not belong, the first of which relate to the audio processing. When the microprocessor encounters this corrupt data in the audio (or even video) registers, it interprets it as the start of a shut-down, and mutes the audio (and/or

video).

When the unit is unplugged and replugged, it empties these registers of the corrupt data.

It is good to know that this problem was resolved in newer chassis designs that use 32-bit microprocessors (i.e. MM101/102 and DTV306/307).

But the vulnerable Thomson televisions will do this as they are receiving invalid data from a station to which the MAIN TUNER is tuned. This is why it is so important to find out what channel, and more specifically, what program the viewer was watching at the time of the anomaly.

The real solution: Broadcasters can upgrade their equipment so that the data they send is valid (includes the necessary truncation packets), so that their signal is always 100% valid, and does not mess up these Thomson receivers. Some retailers have someone assigned to contact suspected broadcasters. Once the customer identifies the program (or commercial) was being watched (including the time of day) when the incident occurred, they should report it to the home service specialist.

A final note: XDS data may be inserted live, or played back on video tape by a broadcaster. It can also show up on a VHS tape that the customer recorded from a previously-aired television program.

So the fix is to place a 1mfd capacitor to ground on U13101(15). This swamps the closed caption data to the micro and stops the reception of the defective data packet. In the event that later on the resolve the defective data problem the capacitor can be removed. the closed caption feature will not work with this cap. installed.

Oh Boy !! Not this again....

Not What ?