Mulja tv repair portal
Equipment Repairs => CRT TV forum => Topic started by: Frank on January 23, 2007,20:13:39
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Hi Guys,.Me again,This set had good pic after i did some convergence adjustements,but now the set runs great for 45 minutes, and sudden gets a Horizontal 5 inch pic top to butom and fades away with no raster just blunk screen, but sound is good,at first if i unplugged from the wall and let tv sit for awhile and plugged in back again it would come on, but latly it doen't come on no more,has no lit at the yoke, Took some tests,i have 165v at the big cap,175v fluctuating at colector of the hot,and 318v at g2 in the crt board with crt socket plugged in or out, also have only 40v at red green and blue drivers emitter, when should have 135,138 140. Hei i have changed chassis put in one ctc 177AF and set is running great. so tube is good.
Also i suspect either flyback, or hot under load, i'm going to unsolder the hot and measure it out of the circuit , testing with the ohmeter in place i should have 20ohms, but i only have 12 ohms,but i'll check it out,i don't want to spend any money on this set. that i'm not shure what component is bad, i also went through all resistors and the seemm alright allthough some are a bit discoloured with the hit. i also have an elctrolict cap in the crt board that is high ESR but i am not shure that is the cause off shut down ,any news i'll post thanks. Hei i have changed chassis put in one ctc 177AF and set is running great. so tube is still in good shape
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Please find a list of faults for your tv
CTC197CE2 et tries to come on 3 times, if unsolder collector of horizontal
>o/p chassis will run. A: Dead, pulsates three times, unsoldering collector
>of horizontal output transistor found that set would start (power supply was
>OK). If set starts replace IHVT (flyback). Common on this chassis
>
>Proscan Model # PS36125 Chassis # CTC197CG Q: HZ Output Transistor Failure
>A: Unsolder, scrape leads, and resolder coil between HZ Driver Transformer
>and Base of HZ Output Transistor
>
>RCA Chassis # CTC197CG Q: HZ Output Transistor Failure A: Unsolder, scrape
>leads, and resolder coil between HZ Driver Transformer and Base of HZ Output
>Transistor
>
>PROSCAN CTC197AD3 HSPF# 4176 RCA CTC197AC HSPF# 4113 RCA CTC197AH HSPF# 4229
>RCA CTC197AH2 HSPF# 4196 RCA CTC197AH3 HSPF# 4296 RCA CTC197AK2 HSPF# 4066
>
>RCA CTC197CA HSPF# 4052 RCA CTC197CJ3 HSPF# 4389RCA CTC197CK HSPF# 4389
>
>RCA PS27600 CTC197All snow Unit has no tuning of any channel from the main
>tuner. When monitoring the tuning voltages at U17501(5,6,7,& 8) were all
>running at 30 volts no matter what channel the TV was on. Inspecting all the
>tuning voltage paths from the PLL chip U17501 found that the path that Pin 5
>supplied had a 52K resistance to ground. On the other side of R17508, a 47K
>resistor we found the resistance path to ground was 4.2K. Capacitor C17713
>was leaky. PN# 192020.
>
>
>PS32109 CTC197Arcing Serial # 738560420J Unit will not turn on but there is
>an arcing in the neck of the tube. Unit has a defective CRT. CRT #
>A80AEJ16X09 VLS # TG9194-AF
>
>Proscan PS36500 CTC197Arcing (Snivits) 36 " ctc197 that has a weird symptom.
>First of all, its intermittent. second its not affected by freeze or heat.
>symptom is picture starts to get horizontal tearing and break up
>and 1" vertical band of snow band on the left side. It will get worse and
>eventually take over picture and the flyback and yoke starts making a
>sizzling type noise and then all of a sudden it just stops. Also does it
>in aux input mode. The interference was picked up not only by other tvs in
>the shop but also by radios. NOTE: I started working on this in customers
>home and found that the ground pin for the focus/screen controls was
>completely open, I soldered it back but at the time didn't give it allot
>237506 flyback was cause. I just bet
>this was the cause of this rare problem
>
>
>RCA F36690 CTC197 Auto program Takes too long to change channels Will not
>autoprogram. But it will manually program and store all the channels in the
>memory.Tech needs to initialize the EPROM with the chipper checker and
>create a file for the product. It may require the alignment of the IF VCO or
>IF APC. Each one will cause the set to be sluggish and Cause the set to not
>auto program 100% of the time.
>
>RCA PS27500 CTC197AUTO PROGRAM Tuner skips several channels when using the
>auto program feature.Unit had a broken trace at C509
>
>RCA PS36700 CTC197AUTO PROGRAM Unit has two symptoms. 1. If the channels are
>direct accessed the set will take 15 seconds to before the picture would
>show up. 2. When the volume, brightness, contrast, etc. is adjusted the set
>will take too long for the execution of the function. The bar graph will
>take 1o to 15 seconds to execute the next level up. The T4 chip VCO is not
>running at the correct frequency. When measuring the U16201(12) we found the
>voltage too high (7+ volts)`. When the set is placed on a active channel,
>and the voltage is checked on this pin it was over 6.8 volts. Using the
>chipper checker we were not able to reduce this voltage lower than 4.9
>volts. It must be 3.8 volts + or - 0.8 volts. It is suggested the VCO coil
>be replaced (L12302) part number 215502
>
>RCA PS36700 CTC197 BAR ON SCREEN Unit operates fine intermittently but the
>lower portion of the screen has a 50 IRE bar that matched exactly the size
>of the PIP box. When the PIP box is invoked and
>moved up the screen the 50 IRE bar moves with it.Because of the thorough
>description of this symptom it appears the trouble must be in the FPIP IC
>U18100. This IC is used for the PIP and comb filter for both main and pip
>video.
>
>PS36605 CTC197 BLUE SCREEN Unit has a blue screen. Cannot achieve cut-off
>with G2. When tapping on the neck of the tube the blue screen returns to
>normal but will turn blue again in a few seconds.Tech will need a
>replacement CRT A90AEJ16X09. CRT approved by TCE tech line.
>
>RCAF36680CTC197CHANNEL CHANGE INOPERATIVEF36680 serial 831331772X Unit will
>not change channels. The display changes but the internal tuner will not.
>Seems to be stuck on channel 9.Tech needs to deselect all entries in the TV
>guide plus menu relating to the questions; Do you have a CATV BOX? Do you
>have a VCR? Do you have DSS?. Select "NO" to these items. It will give the
>tuner control functions back. If any of the items are selected "YES" then
>the customer will need a device that came with the set called a
>IR Blaster. It plugs into the rear of the set in the "G-LINK" connector. It
>enables the TV to "Talk" the VCR or CATV box Through the IR G-LINK. It will
>control them if the user wants to have the TV Guide plus put the VCR
>into record (timer type recording) or when the TV downloads the TV Guide
>plus data, It must search for a Host Television station that transmits the
>TV-GUIDE PLUS data. The TV change the channels on the CATV BOX rather than
>the TV if the only input to the set is a CATV BOX.
>
>PS36700 CTC197 CHANNEL CHANGE INOPERATIVE Unit has no tuning of VHF channel
>even though the channel display is changing. Checking the band switching at
>Q17503 Q17504, & Q17505 finds that everything is OK in those areas for low
>and high band VHF and UHF switching are OK. When monitoring
>the tuning voltages generated from the Quad OP amps in U17501(5,6,7,& 8) we
>found that pin 5 was the lowest voltage of all of the other pins. These is
>the tuning voltages for all the vaircaps in the tuner area. Pin 5 it
>the tuning voltage for the Local oscillator. It never went higher than 1
>volt no mater what channel was selected. Checking the resistance to ground
>on pin 5 we found it to be less than 1k it should be in the 20 megs +.
>Removing C17508 removed the load on that line and corrected d the fault.
>Capacitor PN is 197600 1000 @ 50 vdc SMD.
>
>RCA F27615 CTC197 Chipper Checker Unit operates fine but it does not show
>the usage display in the menu provided in the chipper checker dialogue
>box.All sets were tried out with the newest version of
>Chipper Checker. After loading the new version of the software Chipper
>Checker II ver 1.61, It was discovered the screen size in the selected in
>the computers display was set to 800X600 instead of 640X48
>
>RCAF32635CTC197CRTF32635S On bright white areas of the screen the screen
>temperature will change slightly and slowly return to normalThis is known as
>doming and is normal on most all picture tubes. It is caused By the
>expansion coefficient effect of the shadow mask inside the tube. As the
>bright beam passes through the holes in the shadow Mask the shadow mask
>heats up in that geographic area of the mask. Since that area is hotter than
>the surrounding area it expands more the cooler surrounding area. This
>causes a doming or a blistering effect of the mask causing the "Q" distance
>to change. The "Q" distance is the optimum distance between the surface of
>the shadow mask and the phosphor dot on the CRT face.
>
>RCA F36673 CTC197 CRT Unit has a blurry picture and arcing in the neck of
>the tube. Unable to check the Voltages at on the socket with tube
>disconnected due to sporadic arcing from the pins of the CRT A90AEJ15X01
>unit has blurry focus and arcing in the neck of CRT
>
>PS32109 CTC197 CRT Unit will not turn on but there is an arcing in the neck
>of the CRTUnit has a defective CRT. We will need a RCA approval from Thomson
>for this unit. Tube serial #D-YAGA8516 Code date 97-28, CRT # A80AEJ16X09
>VLS # TG9194-AF
>
>RCA PS32500 CTC197 Dead Unit is dead will not power up. Unit appears to have
>normal data and clock and all B+'s appear to be normal.Unit has DATA Clock,
>Reset, B+, on all components that connect to the T-4 chip. Q14301( C) was at
>36 volts all the time. It never changed from stand by to run mode. There was
>Horizontal drive to Q14301(B) at nearly 2 volts peak to peak. This high
>drive voltage indicated that Q14301 base was open, and it had a
>emitter/Collector leakage. Replaced Q14301 PN# 146851
>
>
>PS27500 CTC197 DeadUnit has no standby voltages Secondary B+ is pulsing. All
>voltages on secondary are pulsing at about 1/2 of their normal
>values.Checking all the silicon components in the primary I found a 10 ohm
>short across CR14102. This was caused by a shorted C14147 1.5 mfd @ 100vdc.
>Part number 214049
>
>
>RCA F36674 CTC197 dead Power supply is squealing nothing noticeably burned.
>But an ohms check on Q14401 fins a 30 ohm to ground. Checking the following
>components we found C14401, and CR14401 & Q14802 shorted. It is suggested
>that these and the following components be replaced, C14410, C14800,
>CR14800, CR14401.
>
>PS36677 CTC197 DEADF bad flyback transformer Now main B+ current and
>horizontal timing pulse
>are normal. When power is applied plug-in B+ at collector of horiz out
>starts out about 140V, but then runs away to over 170V and resistor R14126
>(30K) goes up in smoke. Tech statically checked the surrounding
>components, and they checked OK seem to check OK.R14126 is in the snubber
>circuit. If that guy blows you will need to replace C14122, CR14122, and
>C14128. Back EMF from T14101 is killing this resistor because one of the
>components in the snubber circuit has failed. As long as the flyback does
>not have a short circuit in the primary winding to ground, the power supply
>will produce approx. 165 vdc at CR14106(K) with no load. Static checking the
>components listed above will not tell you the true story about their health.
>REPLACE THEM!. Note: follow up----The device that was bad is CR14122.
>
>RCA PS27500 CTC197 dead shorted Chopper transistor Q14101 and a open R14145.
>These items were replaced but still no operation of the SMPS.It is a mystery
>why the resistor R14145 would be open and the FET Q14101 too. It is possible
>the set may have been hit with a line surge taking out the R14103 too. What
>is known is the set has no stand by voltages and no noise from power supply.
>Unit had defective Q14101, R14145 & R14103. Replacement corrected the fault.
>
>RCA PS27500 CTC197 dead shorted Chopper transistor Q14101 and a open R14145.
>These items were replaced but still no operation of the SMPS.It is a mystery
>why the resistor R14145 would be open and the FET Q14101 too. It is possible
>the set may have been hit with a line surge taking out the R14103 too. What
>is known is the set has no stand by voltages and no noise from power supply.
>Unit had an open in the trace
>from the R14103 to pin U14101(6)
>
>RCA PS32109 CTC197 dead Unit will not power up. No LED flashing in front.
>When checking the standby voltages from the output of the SMPS we found the
>supply has all stand by sources except the 16 volt source from CR14107.
>Further inspection finds that CR14107 has a severed leg at the body of the
>device hidden by its ferrite bead.
>
>RCA PS32500 CTC197 dead No secondary supply voltage in the stand by mode.
>All raw DC voltages are
>there in the primary sideAll primary voltages of power supply are present
>with the exception of U14101(3) which was "0" volts DC. This is one of the
>initial start up voltages for the Power Supply regulator IC. R14145 a 270K
>resistor was open in the primary of Power supply. Replacing it corrected the
>fault.
>
>RCA PS32500 CTC197 dead No secondary supply voltage in the stand by mode.
>All raw DC voltages are
>there in the primary sideAll primary voltages of power supply are present
>with the exception of U14101(3) which was "0" volts DC. This is one of the
>initial start up voltages for the Power Supply regulator IC. R14145 a 270K
>resistor was open in the primary OF Power supply
>
>RCA PS32500 CTC197 dead No stand by voltages from secondary of power supply.
>No oscillation from SMPS.Checking the e Soft start B+ at U14101((3) finds it
>to be "0" volts. D.C. resistance to ground is Approximately 5K (Normal)
>R14145 open (270K 1/2 watt) P N #193067
>
>RCA PS32500 CTC197 dead No stand by voltages from secondary of power supply.
>No oscillation from SMPS.R14145 open
>
>PS36605 CTC197 Dead Resoldered the tuner for intermittent reception. Now the
>set is dead. All stand by
>voltages are normal.Checking the DATA and CLOCK lines on U13101(3 & 4) find
>they are 13K resistance to ground. The same is true with U17501(18 &19) This
>indicates the I2C bus is not shorted or open and nothing bad happened in the
>resoldering process of the tuner. I next had the tech cut jumper wire
>JW12410 located at LL8 on the deflection circuit board. This turns on all of
>the switched Post regulators U14701, U14104, U18101... etc. Once confirming
>these regulators were running the next test was to see if U16201(20) had B+.
>It must be 7.5 vdc. In this unit the voltage was zero volts. It was
>discovered that there was no voltage at R14102. Following the traces to
>JW12143 location MM3 finds that one side of the jumper was torn loose from
>the trace. This apparently happened during the servicing of the tuner.
>
>RCA PS32500 CTC197 Dead No secondary supply voltage in the stand by mode.
>All raw DC voltages are there in the primary side.All primary voltages of
>power supply are present with the exception of U14101(3) which was "0" volts
>DC. This is one of the initial start up voltages for the Power Supply
>regulator IC. R14145 a 270K resistor was open in the primary of the power
>supply.
>
>RCA F36674 CTC197 Dead Power supply is squealing. A visual check of the
>supply finds nothing noticeably burned. But an ohms check on Q14401 finds a
>30 ohm to ground. Checking the following components we found C14401, and
>CR14401 & Q14802 shorted. It is suggested that these and the following
>components be replaced, C14410, C14800, CR14800, CR14401.
>
>RCA PS32109 CTC197 Dead Unit will not power up. No LED flashing in front.
>When checking the standby voltages from the output of the SMPS we found the
>supply has all stand by sources except the 16 volt source from CR14107.
>Further inspection finds that CR14107 has a severed leg at the body of the
>device hidden by its ferrite bead. There was not enough lead to connect it
>to the board. Replacement corrected the problem.
>
>PSNPS27500CTC197DeadUnit will not turn on. If the Secondary B+ finds it
>pulsing. All voltages on secondary are pulsing at 30% of their
>values.Checking all the silicon components in the Primary I found a 10 ohm
>short across CR14102. This was caused by a shorted C14147 1.5 mfd @ 100vdc.
>Part number 214049
>
>RCA PS32500 CTC197 Dead Unit will not turn on. Unit does not have any action
>of LED's on front.U13102(8) the EPROM we find 5 volts but the reset on the
>CPU- U13101(51) finds it running at (0) volts instead of 5 volts. Micro is
>stuck in reset. Measuring the voltages at the secondary of T14101 finds that
>all the voltages at each diode is correct with the exception of CR14107(C)
>They should be 15 volts but it was only 8 volts. Checking the voltage at the
>filter C14106 finds the voltage is "0" volts. There was a hairline
>separation in the trace between CR14107 and the high side of C14106.
>
>RCA PS27500 CTC197 Out of focus band across the screen that related to
>contrast in the pictureUnit has
>defective CRT. When moving focus control through its range the band get
>thicker and spreads wider. Unit has defective CRT
>
>RCA PS27500 CTC197 Out of focus band across the screen that related to
>contrast in the pictureUnit has defective CRT
>
>PS35500 CTC197 HIGH VOLTAGE Unit will turn on but not develop high voltage.
>When the flash on set is turned on the power led will light up but it will
>only flash 3 times then stopLED will flash if there is no high voltage, and
>it will try to restart. The collector of Q14401 and Q14301 measures 165 vdc
>in the stand by mode. When the set is turned on the voltages drop to 133 &
>80 volts respectively. I asked the tech to jumper Q1440
>
>
>PS35500 CTC197 HIGH VOLTAGE Unit will turn on but not develop high voltage.
>When the flash on set is turned on the power led will light up but it will
>only flash 3 times then stopLED will flash if there is no high voltage, and
>it will try to restart. The collector of Q14401 and Q14301 measures 165 vdc
>in the stand by mode. When the set is turned on the voltages drop to 133 &
>80 volts respectively. I asked the tech to jumper Q14401(E&B) together and
>turn on the set and measure the collector of the Q14301(C ). It was
>
>
>PS36605 CTC197 HORIZONTAL Unit has a symptom in the video where if vertical
>lines were to be displayed on the screen they have a horizontal time base
>jitter. The Jitter causes the lines to e broken up into what appears like
>dots across a 1/2 wide area from the left and right of the vertical line.
>This only appears on the extreme left and right side of the picture and
>quickly diminishes as we look at the second and third vertical from the far
>sides. I had tech short the Pin modulator diode CR14800, and see if this
>symptom disappeared. It did. The trouble is caused by some high frequency
>ripple or noise in the pin modulator circuit. Checking with oscilloscope the
>source of the E/W pin correction at U16201(17) was very clean. However at
>the second output of the dual op amp U14802(7) was very noisy. A slight
>parabolic waveform could be seen but had a lot of high frequency noise on
>the leading edge of the parabolic wave. Closer inspection of the board found
>the C14804 a .027 mfd SMD had fallen off the board. After reinstalling the
>capacitor the vaveform cleaned up with almost no high frequency noise.
>
>RCA PS36605 CTC197 horizontal TV has flagging at the top of the screen. This
>is intermittent. Horizontal and vertical sync is extracted internally in
>U16201. The video must be a minimum of 1 volt pp measured at
>U16201(38). This television was only 800 mv. However at the C12710(minus) we
>had 1.1 volts pp video, where the other side we only had 0.8 volts. The ESR
>of this capacitor was over 150 ohms. Unit had defective Capacitor. C12710
>
>RCA PS32500 CTC197 LINE Unit has bright screen with retrace linesUnit has
>200 vdc source voltage from the cathode of CR14702. But on the CRT driver
>board a resistor R15108 is burned up. This resistor is attached to theG1
>supply for the CRT. It may be possible the CRT arc A80AEJ16X09 tube ser
>D-WBLTG055 code date L28GE17. DOP is 1-17-99.
>
>PS36605 CTC197 PIP When the PIP is turn on the PIP has a sever stretch to it
>and will not correctly position itself using the remote control. The Square
>box for the PIP gets stretched across the screen when trying to move to the
>opposite side of the screen.U18101 is the only thing that will cause this
>problem It is the F2PPIP chip. It handles all PIP insertion functions, Comb
>Filter operations for both PIP and Main. Tech changed U18101 and solved the
>trouble.
>
>RCA PS36700 CTC197 PIP Unit operates fine intermittently but the lower
>portion of the screen has a 50 IRE bar that matched exactly the size of the
>PIP box. When the PIP box is invoked and moved up the screen the 50 IRE bar
>moves with it.Because of the thorough description of this symptom it appears
>the trouble must be in the FPIP IC U18100. This IC is used for the PIP and
>comb filter for both main and pip video.
>
>RCA PS32500 CTC197 REMOTE. Unit has no remote control functions. Unit has
>all functions on the front panel keyboard. When checking the Data out of the
>IR receiver all we are getting is a 5 volt high. No part number is listed
>for this item in the ESI or parts finder software. Unit has defective
>IR13401 IR receiver part number 245282. This is the all plastic opaque type
>
>RCA PS32500 CTC197 remoteUnit will not operate with remote. All functions
>operate on front panel keyboard.Unit has all functions on the front panel
>keyboard. When checking the Data out of the IR receiver
>all we are getting is a 5 volt high. No part number is listed for this item
>in the ESI or parts finder software. Unit has defective IR13401 IR receiver
>part number 245282. This is the all plastic opaque type
>
>RCA PS36500 CTC197 REMOTE Unit has poor remote sensitivity. MK2198. Unit was
>serviced before for the same trouble but it appears it was not corrected.If
>the IR. receiver is pulled out from inside the television the remote control
>works fine. Observing the cabinet opening where the IR. light, from the
>outside world comes from we find a solid piece of plastic covering any type
>of lens of IR. band pass filter that might be built into the cabinet. It is
>unclear how this IR. information is getting to the IR. receiver if the area
>exposing the IR.
>receiver is shadowed by a solid black piece of plastic. Tech need to order
>the mask assay. MK2198. But when the Mask came in the piece that held the
>IR. sensor was missing from the Mask assembly.. Called Larry May at RCA the
>part number of what we need is 243585.
>
>
>RCA PS32500 CTC197 Unit has no remote control functions. Unit has all
>functions on the front panel keyboard. When checking the Data out of the IR
>receiver all we are getting is a 5 volt high. Unit has defective
>IR13401 IR receiver part number 245282.
>
>PS27500 CTC197 shutdown Unit will not turn on unless we forcing the set on
>by entering the service mode. When the error codes are 128, in P1, P2, P3.
>This indicates the audio decoder failureChecking the B+ to the U11600(22) we
>found only 1.1 vdc on this chip. At the Q11600(E) had only1.1 volts and
>Q11600(B) was 1.3 volts. It was discovered that C11629 located at the base
>of Q11600 the 9 volt regulator turned into a 42 ohm resistor.
>
>RCA PS36500 CTC197 SHUTDOWN Unit goes into immediate shut down at power up.
>Checking the high voltage the set will develop high voltage but will shut
>off and cycle on and off. If we disable the horizontal output transistor and
>try again, the set , obviously not achieve high voltage but it should stay
>on and provide a horizontal drive signal unit the set is turned off. This
>was not the case here. The set continued to cycle on and off and provided
>good horizontal drive at Q14301 horizontal driver transistor. U13101(37) is
>the only pin that never goes high when training book says it must be 5 volts
>in the run mode. When checking the other CPU "Must Haves" we find nothing
>unusual. All B+ sources for stand by and run are normal. Unit approved for
>IFS
>
>
>PS27600 CTC197 Unit will intermittently shutdown and my not be able to turn
>back on for hours. The set will not record any error codes.It was by chance
>that we were monitoring the reset pulse at U13101(51). This
>line went low and did not return to normal 5 volts unless we heated the area
>around 1 ~5 & A ~ E. These are located on the corner of the CBA. Checking
>the reset transistors finds that Q13503(B) was at .6 volts
>keeping the reset on U13101(51) low. Checking back to find he source of the
>0.6 volts we found the voltage was increasing as we got further away from
>Q13503. We finally measured both sides of C13504 ad found that both sides
>had voltages 5 volts on one side an 3.3 on the other. Capacitor is a .1 mfd
>at 50 volts PN# 190552. Replacing it and cleaning off the red glue corrected
>the problem.
>
>PS32600 CTC197 No tuning All snow. Determined that the unit was band
>switching. Checked for 33v supply at pin 4 of PLL chip (U17501), "0" volts.
>Checked 18 ohm 2watt resistor R14159 for open. Resistor was good. Had 140
>volts on one side and next to nothing on the other. Checked resistance
>
>PS32600 CTC197 No tuning All snow. Determined that the unit was band
>switching. Checked for 33v supply at pin 4 of PLL chip (U17501), "0" volts.
>Checked 18 ohm 2watt resistor R14159 for open. Resistor was
>good. Had 140 volts on one side and next to nothing on the other. Checked
>resistance of pin 4 U17501 and found it to be 63 ohms to ground, (sounds
>like me trouble). Eliminated u17501 by lifting pin 4, also lifted several
>other parts off of the 33v line. Finally found that the short was
>originating from the pip tuner. The 33v is fed to both tuners. By
>disconnecting the plug restored normal tuning to unit, thus verifying that
>the main tuner was ok. Continued to check for shorts......Found shorted SMD
>C17407 on the 33v line on the pip tuner board. Replaced and restored normal
>operation to entire set. Fix: Replace shorted C17407, part# 197600.
>
>RCA F36674 CTC197 Tuner gain Unit is getting a blank screen stating the
>words "Weak Signal" Unit is getting Video to the input of U26901(6) but
>nothing out on U26901(13). 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.
>
>RCA PS27600 CTC197 TUNING Unit has a problem where all the channels it
>receives is off frequency. AFT will not pull it inTech needs to look at the
>value of the IF VCO in the Chipper Checker menu. This value can be
>moved up or down as much as 10 digits to see if the effect is will correct
>the symptom or not. Moving the value of this setting does not change the
>symptom.
>
>RCA PS27115 CTC197 TUNING Unit does not have reception above channel 50.
>Previous tech from another service center out and resoldered tuner. After
>tech left and the customer tried to use the set they discovered no reception
>above channel 50Q17504(C) . These are band switching transistors and will
>inhibit the operation of the tuner above channel CATV 50. Unit did have a
>open Q17504.
>
>RCA PS32500 CTC197 TUNING Unit has no reception on any channels. The number
>changes but nothing else on the screen but snow. There is a difference in
>the amount of back ground noise when a channel is
>selected to the different bands with in this tuner.. Checked all the TV
>guide plus setup data found that all was correct. Further hardware checking
>found the Cathode of CR14115 (location 20 MM) only 4 volts. This
>is supposed to be the 33 vdc line for the tuner. Measuring the resistance to
>ground found it to be varying from "0" ohms to 27K while flexing chassis.
>Removing tuner shield revealed FB17203 (CBA location L19) a
>ferrite bead next to the tuner shield had a solder splash on it causing a
>short to the tuner shield and pulling the 33 vdc source to ground.
>
>PS32500 CTC197 TUNING When running the set over a long period of time the
>set will go to snow then back to normal after a fraction of a second. The
>only error code that can be read is error 21. This is not a valid error
>code. Technician resoldered the tuner grounds without effecting the symptom.
>Recommend the tech go back and resolder the PLL and Mixer/Osc U7501, U7301
>in the tuner assembly. These are both surface mounted capacitors. The
>process is to be sure the chassis is totally level, and paint solder flux on
>both IC's. Resolde the pins by wiping the solder from the chip to the tip of
>the leg in strokes. Once this is accomplished then the tuner is thoroughly
>cleaned with flux remover or solvent and a stiff short bristle brush made of
>natural material. NO PLASTIC BRUSHES!!!!!
>
>RCA PS32500 CTC197 TUNING Unit takes too long to direct access channels.
>Will not aurtoprogram.This delay in direct accessing the channel is too
>long.. It should be about 125 milli seconds. The tech needs to
>enter the alignment parameters of the IF and see that the IF-VCO parameter
>is 98 and the AFC OFFSET is 24. Next is to exit out of the service mode and
>disconnect the Chipper Checker. Turn on the set without an antenna connected
>and select a low band VHF channel from 2 ~ 6 and wait for 10 seconds. This
>allows the CPU to time out and will stop searching for a signal from the
>tuner. Next connect the antenna to the television and monitor the voltage at
>U16201(12) It must be 3.8 volts. If not, adjust L12302 CCW for 3.8 volts. If
>the voltage jumps radically replace L12302 part# 215502. In this test unit
>we did have a defective L12302.
>
>
>PS32600 TUNING CTC197CK Unit does not have high band VHF channelsUnit does
>not have band switching from Low band VHF to High band VHF. There is correct
>band switching at U17501(17) but no change in level at the collector of
>Q17503( C). The collector is always -11.5 volts. When tech was indicating
>there looks like a component missing at coordinates K 19. Checking the
>voltages at Q17503(B) finds the voltage swing from channe6 to channel 7 is
>11.8 to .1 volts. This swing is too far for this PNP transistor. There
>should only be a .7 volt drop with respect to the emitter. Unit has a
>defective Q17503. After the transistor was not soldered
>
>RCA PS27600 CTC197 TUNING Unit takes too long for the picture to lock in on
>channel when direct accessed. Also auto programming does not work. When
>measuring U16201(12) we find the voltage to be 5.3 volts. It should be about
>2.9 volts. This voltage is the AFT crossover voltage. To set this correctly
>you must disconnect the antenna and direct access a local channel strong
>enough to receive but not strong enough to receive without an antenna.
>Direct access this channel and wait for 10 seconds then connect the antenna.
>Measure the voltage at U16201(12) It should be 2.9 volts. If not adjust coil
>L12302 so the voltage at (16201(12) is approximately 2.9 vdc. If this
>voltage can be achieved then try to autoprogram the unit. In this unit the
>original voltage was too high and was brought back to normal with a small
>tweak of L12302. Unit is
>functioning fine.
>
>RCA PS27500 CTC197 Tuning Unit will not get channels from 7 to 13 plus most
>of the other CATV channels, yet the low band VHF is perfect. Checking the
>output of U17501(17) and switching the channel from 6 to 7, the voltage will
>swing from 11.7 volts on channel 6 to "0" volts on channel 7. But when
>checking the voltage at Q17503( C) we found the voltage to be always -11.6
>volts no matter what band we were on. It should have swung to a +12 volts on
>high band VHF. Transistor Q17503(B) never changed either. Base and emitter
>voltage was always the same. But the transistor did not measure shorted.
>However replacing the transistor corrected the problem. Part number 215496.
>This is a PNP surface mounted transistor.
>
>RCA PS27500 CTC197 Tuning Unit will not get channels from 7 to 13 plus most
>of the other CATV channels, yet the low band VHF is perfect. Checking the
>output of U17501(17) and switching the channel from 6 to 7, the voltage will
>swing from 11.7 volts on channel 6 to "0" volts on channel 7. But when
>checking the voltage at Q17503( C) we found the voltage to be always -11.6
>volts no matter what band we were on. It should have swung to a +12 volts on
>high band VHF. Transistor Q17503(B) never changed either. Base and emitter
>voltage was always the same. But the transistor did not measure shorted.
>However replacing the transistor corrected the problem. Part number 215496.
>This is a PNP surface mounted transistor.
>
>
>Proscan PS36500 CTC197 tuningUnit has no UHF or CATV reception above channel
>50 on the main tuner. However the PIP tuner works fineChecking the
>bandswitching at U17501(14) finds the bandswitching is fine when switching
>from CATV channel 50 to 51, but when checking Q17505(C ) the voltage is
>always 11.5 volts. Q17503(B) swings from 0 to 11.2 volts during
>bandswitching. Transistor Q17405 is defective. Part # 231534. This is a
>digital transistor and it checked open using the diode check mode on a Fluke
>77.
>
>RCA PS32500 CTC197 TURN-ON INOPERATIVE Unit will not turn on. Unit does not
>have any action of LED's on front.U13102(8) the EPROM we find 5 volts but
>the reset on the CPU- U13101(51) finds it
>running at (0) volts instead of 5 volts. Micro is stuck in reset. Measuring
>the voltages at the secondary of T14101 finds that all the voltages at each
>diode is correct with the exception of CR14107(C) They
>should be 15 volts but it was only 8 volts. Checking the voltage at the
>filter C14106 finds the voltage is "0" volts. There was a hairline
>separation in the trace between CR14107 and the High side of C14106.
>
>RCA PS36700 CTC197 TURN-ON INOPERATIVE Unit will not turn on. Television has
>all of the necessary voltages at the System control and standby supplies.
>U13101(19) never goes high when the power is
>pressed. Unit cannot be forced on By pressing and hold menu, Then power then
>volume up then release
>
>PS32500 CTC197 TURN-ON INOPERATIVEUnit will run for a while until the set is
>turned off. Once off then turned on again the set will not turn on. No LED
>illumination or auto start attempts will occur until 30 to 40 seconds of
>wait time. After this wait time the set will turn on just fine. No other
>malfunction. Error codes in tech menu indicate error 16 stuck bus.Checking
>the "Run" Data and clock signals during the power up sequence we found the
>set did not correctly start up with clean signals. There were signals within
>the 5 volt peak to peak
>pulse train that were lower than the bulk of the pulse train. By
>substitution U18100 F2PIP chip was causing the trouble.
>
>PSNPS36500CTC197tURN-ON INOPERATIVEUnit will not turn on. Pushing the
>power button makes (U13101(19) go high, but he TV still will not turn on.
>While checking the "RUN" data/clock lines on U13101(3&4) we discovered the
>data line was running at 1.9 volts peak to peak not the 5 volts
>pp.Unplugging the TV and measuring the resistance to ground on the
>U13101(4) "RUN Data line finds it to be 1.8K verses the clock line (3) at
>13K.. Measuring the resistance to ground at each peripheral the uses the
>"RUN" data line we found the resistance drop to 745 ohms at Q18102(c ).
>Removing this service mounted transistor caused the solder land for the
>collector to go to 13K. Replacing the device corrected the trouble. Part #
>219412. This is a NPN SMD transistor.
>
>RCAF32645CTC197TV GUIDE PLUSF32645 Serial 520287768 Customer operates
>television on a satellite system. He is too far from the city to receive
>local television and is not supported by CATV. Customer does not want TV
>Guide to operate.There is no was to disconnect the TVG from the set that
>Thomson will approve, but the tech can enter and illegal zip code into the
>system and cause it to shut down. And illegal zip code could be 99999.
>This should stop it from trying to download anything.
>
>RCAPS32600CTC197TV GUIDE PLUSPS32600 serial 912631148 TV guide plus does
>not load data. In the TV guide set up mode the customer answered yes to
>the VCR. He should not unless he is using their blaster to communicate to
>the VCR. Cust does not have the IR blaster. So the answer to all the
>question in the TV guide plus set up must all be "NO". I order for the
>tech to do this he must enter a zip code of 99999, then finish the setup
>process. Wait for 5 minutes, at which point the set will default to an
>error condition due to the illegal Zip code. Then enter the correct Zip
>code and wait for the next down load time.
>
>RCAPS32700CTC197TV GUIDE PLUSPS32700 serial 836531479. Unit will not
>download the TV guide Plus info to make the VCR recordI 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 other.
>
>RCAPS36500CTC197TV GUIDE PLUSPS36600 serial 846331490. Unit does not
>always download TV guide plus data. Customer has a VCR, and is on cable
>TVThe customer has the VCR connected in series with the R.F. path where
>the CATV from the street goes into the VCR then out of the VCR to the
>Television. Customer must watch the VCR on channel 3. This is not the best
>hook up of the VCR in this application. When used in this manor the
>customer must used the IR blaster that came with his television. This way
>the TV will control the VCR through the IR blaster and the TV will
>download the Gemstar data by using the VCR tuner. One drawback from this
>configuration is the VCR needs to be on all of the time, and the TV will
>always be on channel 3.
>
>PSNPS36500CTC197VERTICALPS36500 Unit has no vertical sweep. The horizontal
>line is elevated 2 inches above center. Monitoring the yoke voltage we
>found 23 volts. Also the 13 volt supply was at 22 volts. However when
>disconnecting the vertical yoke winding the 13 volt voltage return to
>normalChecking the vertical output for damaged or burnt components found
>nothing. But when heating the area around the T-4 chip U16201 we found
>that components in the area where vertical drive comes from full sweep
>returned. Spot heating of C14501 & C14503 caused the vertical sweep to
>return. Removing the capacitors and cleaning the component adhesive the
>capacitors and Board are defective
>
>PSNPS36700CTC197VERTICALPS36700 Unit has vertical over scan and the
>picture is tilted. Tech needs to know where the parameters are that
>control this values.Suggest the tech get into the customer menu and select
>screen. Once in the screen menu select Picture tilt. Adjust PIX tilt so
>the image is level. Next Enter the tech menu and select the parameter 10 &
>11or vertical centering and vertical size. Adjust for normal scan and turn
>the set off. This action will store the values.
>
>PS36605CTC197verticalUnit has weak vertical sync lock. Horizontal
>OKHorizontal and vertical sync is extracted internally in U16201. The
>video must be a minimum of 1 volt pp measured at U16201(38). This
>television was only 700 mv. However at the C12710(minus) we had 1.1 volts
>pp video, where the other side we only had 0.7 volts. Unit had defective
>Capacitor. C12710
>
>RCAF36670CTC197verticalUnit made a loud squeal in the back of the set then
>the vertical sweep became very distorted. The bottom of the picture was
>pulled up and the top very stretched. Tech needs to check the presence of
>the "Half voltage supply" a 13 volts supply at the flyback. Unit had a
>shorted CR14703 =207878(large) and a open R14705= 829A10. This supply
>provides the necessary bias for the input of the vertical output IC.
>
>PSNPS36500CTC197videoPS36500. Serial # 927631446 Unit has intermittently
>looses video but still has sound. Does not have the symptom if using the
>External video input. Suggest the tech look at the Input switching area
>for the trouble. Assuming the set never looses the video when running in
>the External input mode, and the set still has sound it logically limits
>the possibilities to The input switch U26901. This IC is responsible for
>the routing of 4 different video sources from 4 different inputs. If
>everything works in the Video input mode and in the tuner mode there is no
>video then It would suggest the trouble is located in the Switching IC.
>(Based on the techs initial observation that the set had audio in the
>tuner mode.
>
>PSNPS36700CTC197VideoPicture contrast is abnormal in a band that covers
>the bottom 1/3 of the screen. This can be seen in the oscilloscope when
>viewed at U18101(41) when looking at the vertical rate 2 milli seconds.
>Pattern generator was set to gray scale vertical bars. Comparing the video
>at U18101(51) to pin 41 the difference was significant.Unit has an
>artifact that matched the window position for the PIP frame. It caused the
>transparent horizontal band at the bottom 1/3 of the screen. It was on all
>inputs. This was caused by the F2PIP chip. Part # 248640
>
>PSNPS27500CTC197video 1 missingUnit has no video when using the video 1
>input. We were able to track composite video from the video input of
>U26901(3), however nothing on the output side U269011(13).Monitoring
>composite to the input of the FPIP U18100(51) is OK. But there was no
>output on Pin 41. Oddly enough when we fed video into the Video 2 it
>worked as expected. Also Tuner mode operated fine. On other significant
>symptom not complained about was this TV did not have video in the S-video
>input. We could trace the Luminance from the S-video input to each side
>C26916, but nothing at he Input of IC18101(3). It was discovered that
>C18105 was open. Replacing the capacitor corrected both symptoms, both
>S-video and Video 1. The explanation of this phenomena was because the
>S-video input was essentialy open because of the open capacitor the F2PIP
>automatically switched to the input selector to S-video instead of video
>1. The design of the F2PIP chip senses activity on U18101(3) and it
>automatically switched inputs. This input was unterminated and noise got
>into the inout falsing the internal switch.
>
>PSNPS27500CTC197VIDEO NOISEPS27500 serial 849631568. Unit has heavy black
>and white horizontal dashes on the screen that are 3 to 4 inches long,
>that cover the entire screen. It does have On screen display and menu
>functions. I hade the tech check the luminance out of U18100(41) We had a
>saw tooth waveform nearly 1 volt peak to peak at 3 micro seconds period.
>This could also be seen at the input U18100(51). However the Output of the
>video switch U26901(13) was clean video. It was discovered that video was
>clean up to BPF circuit after Q18110(E) Capacitor C18101 was broken.
>
>No Video After Changing Flyback I get the OSD and audio but no video signal
>from the main tuner just a blank raster. Screen voltage is OK. I get video
>in the PIP window but when I swap pictures the main screen stays blank and
>only the audio
>changes. The jumper bewtween pins 7 & 8 of the fly is good.
>A: Was the old fly arcing ? If so it probably damaged the video circuit. The
>way PIP is accomplished in alot of sets makes it immune to ABL, which is the
>path by which the fly can do any damage. Even more common is the OSD not
>being affected by ABL.
>With a print you're looking for the pin of the fly at the bottom end of the
>high voltage secondary. Without a print you're looking for a pin on the fly
>with a cutout in the PC board to isolate it. This is so if the fly secondary
>arcs it won't cause a carbon track on the PCB and it also lessens the
>possibility of fire. There should usually be a reasonable positive DC
>voltage there. Some older sets would have the B+ on that pin and be
>resistored down for control of the video, but newer sets use dynamic ABL
>that is not clamped in normal operation. If you see 0V or a negative voltage
>there you are very close to the problem. Once you run it down and get your
>video back, view a high contrast fast moving scene with the picture cranked.
>You might even want to temporarily crank up the sub contrast, which you of
>course return to the old setting when you're done. What you are looking for
>then is compression and rarification of the raster lines. This dynamic ABL
>is used for sweep correction. On a direct view it usually goes to the
>vertical and video. Some projection sets also send it to the E-W pincushion
>as well and sometimes the integration network is a bit complex.
>If you lack a print, get the datasheet for the jungle (LA7612 ?) and work
>back from there as well. While you might have a shorted cap near the fly (in
>the circuit) it is also possible it zapped something that either amplifies
>or buffs the ABL line. The first check I would do is the resistance from the
>ABL pin to ground. If it's shorted start unsoldering stuff from it, or if
>you happen to have a low ohms meter you can find it that way. In a nutshell,
>I'd say it's a 99% chance or better that the problem is in the ABL
>somewhere. I'd go there unless you don't have sync. In case you don't know
>how to test for sync, the OSD will move if you remove the input signal. Just
>FYI if you don't have any OSD you turn up the G2 so you can see retrace
>lines and watch their behaviour when you apply
>or remove a valid video signal. You might not have to even bother, if the
>PIP image is stable you got sync usually.
>
>ProScan Chassis CTC197CG Model PS36125 Resolder the little coil between the
>HDT and the HOT. You usually cannot see the bad connection. I found it the
>first time with a scope. Can cause HOT transistor to fail
>
>CTC197 Intermittent audio. Video OK, All functions OK. Removing and
>reapplying power restores audio 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 affected.
-
Hi.Mulja Thanks alot but There are no faults like the one i have with RCA CTC197AH F27680gy, I just learnd correct me if i'm wrong,>There is an ERROR code,when i enter the service menu #1,#2,#3,are ERROR CODES.and #1 sais 10,and the other two say 0. also i got the code list and it sais 10, this code means FPIP power supply at reset,what you guys think any ggestions,