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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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New info: RCA sound issues.
Calling RCA Tech line...the main Tech taking care of most of
Canada...out of the office till Jan 17 2006. Average phone call to the specified number...ten minute wait....got nobody to come to the phone! Surprise, surprise! Got an E-Mail back from a Broadcast Station with a link. Look he http://www.yorkdispatch.com/local/ci_3388746 Not sure of the exact repair used. Has anyone done this: Try putting a 1uf electrolytic capacitor @ 50vdc from pin 15 of U3101 to ground (+ to pin 15). This mod will also defeat (kill) closed caption. Nobody anywhere is taking the blame, or doing an actual repair, on this huge problem, from what I can find. Cable companies saying, not ther fault. The units I have seen since the new year, work fine for days, after being unplugged, & broght in for service. Anyone have a plan? Here's what I have so far! Excuse me if some info is there twice. RCA no sound issue. http://wa6ati.com/CTC195-197.html http://philips.nl/assets/Downloadabl...Plus+-3312.pdf http://64.233.161.104/search?q=cache...odules&h l=en if you do a control F and search for guide you will come across the Guide Plus info. It is a little difficult to read but what I get out of it is that of the 5 tests shown, the first 2 should definitely pass ( rom and ram ) the 3rd test will pass if you have VBI packets coming in ( mine only passes when I run the diag from channel 47 ABC ) the last 2 tests are for communication between your TV and other devices. in the diagnostic, you can push the numbers 1,2,3,4,5 to rerun the individual tests without going throught the whole sequence again. We have confirmed that guideplus have made changes in their system causing this issue. "Stack overflow" error in the television's Shaw has not made changes to how this information is delivered but are working with guideplus to have them correct the issue. This trouble is caused by a defective data packet broadcast from a local TV station. The data packet is located in the VBI (Vertical Retrace Interval). It's purpose is for XDS (Extended Data Services) that is used by the GemStar circuitry. The condition is very intermittent and not much is known to the average TV technician because Thomson is not releasing much information to the public other than removing the power and reapplying it again. Thomson's answer to this issue is taking their case to the FCC and let them resolve the conflict between FCC and the broadcasters. This phenomena only effects certain Thomson chassis CTC197, CTC195 and CTC203. Only a specific run of serial numbers are also effected. As of this date 7-12-2001 there is no cure offered by Thomson. Yes unplug, wait then plug is only solution for this GEMSTAR lockups. The Gemstar is part of one CPU module that thomson unwisely used instead of using seperate ICs, one for TV microcontroller, gemstar get their own. JVC, and others are using seperate modules and not always present so this is less common than Thomson (RCA & GE TVs) units. Recent basic thomson units don't have Gemstar for last couple years. There is no fix for this. The fault lies with the broadcaster who maintains the equipments that send outs data on line 21 be careful and up to date. We had one happen recently, had to haul the Thomson TV back to customer's. Jack waited not long enough for the micro to "lose power & forget". Not true! There is a fix! But this fix will disable CC functions. Read on! RCA CTC197 & CTC195 & CTC203 # THOMSON AUDIO DROP-OUT NUISANCE FIX 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. A fix that I have been recommending to our techs is to place a 1uf 50V 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. Obviously the closed caption feature will be crippled with this capacitor installed. This has been a topic of conversion most of the day....Try putting a 1uf el.cap @ 50vdc from pin 15 of U3101 to ground (+ to pin 15). This mod will also defeat (kill) closed caption. I kept hearing this mod with result of disabling CC as side effect, and I didn't hear of that like this from RCA's modification data. By the way, I find this UNACCEPTABLE mod; since many users are hard of hearing or deaf (I'm one of these) needs CC. By the way, how often this problem crops up is not that often and I bet there are so MANY similar gemstar modules in many units (CTC203, 195/197, ATC113 models and several more? And the cable providers have the equipment and items that generate data on 21th line, there was a period when there was a feature bug that generated extra bits, but I assume is fixed and from what I see they were very anxious to keep this thing very quiet. Only thing that happens from time to time is glitch that can't be prevented that very occasionally "crashes" these type of gemstar modules and needed a unplugged for 30 minutes to a hour to "reboot" a TV back to normal. By the way ITC008 no longer have gemstar support but I find it cheapened a bit like it no longer can hold channels memorized. Citizen IS cheaper than RCA ITC008 and did have that channel memory stored on eeprom. That's not typical of Thomson's for this. CTC185 is the CHEAPEST chassis of all and did have the channel memorized in eeprom. Go to the Guide Plus Setup. Mark USA, then enter 00000 for the zip code, answer "No", then answer "No". click through the rest of the installation. Then go back and enter everything including your zip. This is suppose to "RESET" the memory. Then turn the TV off for at least 12+ hours. Everything should be back TV Guide Plus TV Guide Plus progrOK, I found it on a Tech site, Enter the guide setup program. On my set it is Menu then Guide Plus. The next menu will show setup at the top. At this point, press GOBack twice and then TV. This resets the Gemstar module and goes into a Diagnostic. If you start this sequence from the channel where you think your data is coming from, the VBI packet info will show data coming in. mming is carried on the local PBS affiliate, Without a Cable box Go thru the normal setup. When the TV is off it will find the TV Guide signal and download the information. With a Cable Box When you set up the Guide Plus it will ask you if you have cable. If you say yes, it will ask what brand the cable box is. This is important when you want to use the TVs remote control, or the Guide Plus features to control the cable box, but not necessary to acquire the Guide Plus information. Important: When the TV is off, leave the cable box tuned to the local affiliate, that downloads the data. Thomson representative on our direct RCA TV line at 1-800-336-1900 Monday - Friday 8 a.m. - 8 p.m. and Saturday -Sunday 10 a.m. - 7 p.m. (EST). turn off the tv while it's set at channel 3 Turn TV off and unplug for 5 minutes. Plug in and turn back on. Go through the TV setup and make sure you manually put in the time. When you get to the GuidePlus setup, scroll over to the SCHEDULE section and remove everything that is in there, if any. (A power outage or unplugging the TV won't delete any scheduled programs.) Go to setup and re-enter your zip code using the up and down buttons rather than the number buttons. Click the OK button after you're finished with GuidePlus setup. Turn the TV off without going back to normal TV viewing. Within 2 hours the GuidePlus menu will show, but it won't show any progrmas yet. It will list channels, but won't tell you what is on. Leave TV off for 12 hours. Note: You can still watch TV without the channels being listed, but it takes longer for the programs to show up. Usually after a period of off time. just talked to 1 800 336 1900. they told me to go to set up and put in usa and then 99999 for my zip finish set up and shut down for 35-45 mins. and then do set up again with the right zip. shut down for 24 hrs. and then see if u have ur listings. I kept hearing this mod with result of disabling CC as side effect, and I didn't hear of that like this from RCA's modification data. By the way, I find this UNACCEPTABLE mod; since many users are hard of hearing or deaf (I'm one of these) needs CC. By the way, how often this problem crops up is not that often and I bet there are so MANY similar gemstar modules in many units (CTC203, 195/197, ATC113 models and several more? Yes there are two types of CTC203 chassis, one is one ribbon with smart chassis (has micro onboard), and other one that uses two ribbons with dumb chassis (no micro on the chassis, the micro is built right into gemstar). The one ribbon you can unplug ribbon cable and remove gemstar module entirely. The two ribbon type, you have only two options, manual reset with remote or unplug and wait for half a hour. Remember to ask customer first before doing the cap modification because some use CC. Guide Plus not working: I asked the tech to enter the TV GUIDE plus set up mode and read me the options in the set up dialogue. When the tech got to the part of the set up that discussed "Do you have a VCR?" It had been selected and it was available on Video 1 only. Unit has TV Guide set up incorrectly. I had the tech enter an illegal zip code (99999) and tell the set up the No DSS, no VCR, and No cable box is present. The illegal zip code will cause a auto reset of the TV GUIDE Plus module and will remove it's hold on the chassis tuner. This corrected the problem. Now the tech will need to reset up the TV GUIDE PLUS correctly I had tech reset the TV guide module by entering the Guide plus setup program the hitting the "Go back" button on the remote then hit the "TV" button twice. This clears the old data in the system and starts a internal test program. It will check the ROM, RAM, VBI, and G-LINK. All passed except the VBI and Glink. The VBI did not pass because it was not on the host channel. The Glink did not pass possibly because the Glink cable is defective or a bad IR blaster at the end of the G-link cable. The G-link is necessary for VCR programming because the television will turn on the VCR via the G-link cable and IR blaster, make the VCR select the channel, and place it in the record mode. Apparently the TV guide plus module was connected incorrectly. The connector J23905 was connected to the front video line input. There does not appear to be any cable from J23905 to J26401. Tech will need to hard wire a jumper from J23905(1) to J26401(2) J23905(2) to J26401(1) Note: these are opposite from each |
#2
Posted to sci.electronics.repair
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New info: RCA sound issues.
It's not just Thomsen. Other manufacturers have different problems
with the same cause (depending on how they handle the two ambiguous bits). This will have to be fixed by the broadcasters, or this generation of tv's will have many problems. Dani wrote: This trouble is caused by a defective data packet broadcast from a local TV station. The data packet is located in the VBI (Vertical Retrace Interval). It's purpose is for XDS (Extended Data Services) that is used by the GemStar circuitry. The condition is very intermittent and not much is known to the average TV technician because Thomson |
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