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Copyright © 1994-2004
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We will not be responsible for personal injury resulting from attempting these repairs nor damage to the equipment that may result from lack of soldering experience or inadequate desoldering or soldering equipment.
Some of the common symptoms include:
The articles in this document have been compiled over the last few months from postings on the USENET newsgroup sci.electronics.repair.
Contributions are welcome to increase the coverage of this set of notes as well as those for the very similar set of problems and solutions for late model RCA and GE TVs: "RCA/GE TV (CTC175/176/177) Solder Connection and EEPROM Problems".
Proper attributions will be made for all providers of solutions. I apologize if I have incorrectly referenced you or left your name off. I will be happy to make any necessary corrections in the next revision. Please email me with any additional sections. I would very much like to improve the details of the repair procedure if possible.
Corrections and additions to any specific symptom or solution are also welcome.
I have no connection with Sony Electronics or any other manufacturer of consumer electronics. These articles have been included unedited except for some spelling, grammar, and format cleanup.
"I have a two-year old Sony Trinitron TV. When it is turned on, picture perfect. But it can only last about 30 mins, then it looks like it has difficulty to receive signal. On its hardly seen screen, you can see all channel display only one TV station signal (I am using cable). After I turn it off for a while and turn it on again, I got good picture again. The time it last depends on the time I turn it off. Occasionally, if it past the first 30 mins, it seems it will be good forever."This may be an actual electronic problem but would still recommend doing the resoldering first.
"I have a Sony KV-27TS20 tv that upon power up will drift back and forth from a clear picture to a whining static fill mess. This happen for about five minutes then the clear picture stays."
"My Sony 27" (Model KV-2782R) is having a problem with the tuner (I think). When the TV comes on, I have no control over any of the functions. The channel changer, display controls, TV/Video selector all have no effect on the TV. I can, however, see the source (VCR/Laserdisc) that is plugged in to my Video 1 jack, but the picture is very dark."
"I have these 2 practically identical (at least on the outside) 13" TVs, and they both have the same problem: they act like if someone was messing with the antenna - the picture comes and goes, or just 'jumps' vertically every couple of seconds, the sound sometimes goes away too (turns into just noise). On the KV-1395 the problem sometimes stops - either the picture is already good at power-up or it just acts up for about 20 seconds and tunes in, the other one is totally unwatchable.
I assume that this is a common problem with these and some other Sony TVs - I remember long time ago someone had posted repair tips on Sony tuners, but I could not find them on the FAQ sites."
One more detail: At power on both the TVs cycle through channels 2-6, with no picture on screen. You have to select a channel for the picture to come on. Is this normal with these models?"
"I'm having a problem with my KV27XBR55 (mines in the XBR series). I realize now that the problem started many months ago when I heard the sound degrading (I thought the sub-woofer had blown). But after moving recently the sound got very bad just before the picture dropped out too.
If I unplugged the set for a while (minutes to hours) it would work for several minutes to several hours after plugging it back in. And... (forgive me! :) a well place thump on the cabinet could get either some video/audio static or actually restore the picture and sound.
I thought the jarring of the move may have loosened some circuit boards or connectors, so I opened the back and reseated every card/connector I could easily reach. That seemed to work but the next day it died again.
When it's having its "problem" I can get a picture by selecting a video input (like the VCR) but no sound."
"This TV works fine for a few minutes, but after warming up it demonstrates a tuner problem. When a channel is switched to, it will take ~5 seconds to lock into the station. Then it will not stay locked in, but instead drift to an adjacent channel for the audio.
I have been reading here for several months, and based on other postings of similar problems, thought I could try to fix this. I read the pertinent parts of Sam's FAQs, and I photocopied parts of the Sams' Photofacts.
The photo of the A-Board shows one tuner box, while I have a box labeled RF-AGC [IFB-450M 1-464-598-11 AE7C20] and Tuner [1-463-603-13 BTP-201 D7011BY]. Adjusting the blue turn knob in the top of the RF-AGC did not improve the problem. I have not adjusted the white turn knob that is in the RF-AGC box. It is difficult to get to because of the proximity of the adjacent Tuner box.
My questions are:
- Should I adjust the knob inside the RF-AGC?
- Should I solder out the Tuner box and replace it?
- Should I solder out the RF-AGC and replace it?
- What will a tuner and/or RF-AGC cost and where can I get one?
I admit to being a novice, but I have enjoyed reading the troubleshooting advice that is discussed here. Although I could take this to a shop, I would like to try and fix it myself." Do not touch any of the adjustments! Problems that happen suddenly or have significant consequences are rarely due to adjustments drifting!
None of the modules need replacing but if you screw up :-) the IF is about $90 and the tuner is about $100. Resoldering all suspect joints will cure your problems.
"Would like to know if any users have discover why the tuner or TV signal fails to work until the set has been on for about 10 minutes. This problem shows up on the VHF channels - the UHF channels will work. A number of the same vintage sets are starting to show the same problem. Any suggestions would be most welcome."
"I turn it on, and after 5 minutess, it goes to static. I can't even play a tape in the VCR (which the signal runs through first)."
"I have a 4 year old SONY TV with a trinitron tube. When the TV is switched on, it does not receive a few station. For some stations it just snows, on others it shows a very distorted view of some other channel. The problem goes off automatically after 4-5 minutes and then there is no problem as long as the TV is on. The lower frequency channels take the longest time to come back. It is a cable ready TV and when we are viewing cable, the lower channels have the same problem. Most of the time the higher band cable stations are ok from the start.
We are thinking that it may be a problem with the tuner. It does not look like heating problem as the problem is there only during the startup. Can it be a problem of the tuner PLL? or is it something simpler?"
"Does anyone know how I can go about fixing a tuner problem with the Sony TV? The tv signal will come in and out, the signal will come in only for about 30 seconds and is gone for about 15 mins. I have checked all electrical cables, cable TV and antenna cables too.
I have tried contacting Sony, they seem don't care about their consumer services. I have emailed them and contacted their Sony Store dealers, and they would only say it would best to buy a new Sony. I personally will not buy another Sony every again.
"I have a Sony 32" console type TV and the model number is KV-32TW75. The TV set is about three years old. It worked perfect until few month ago. When the set is direct connected to antenna through the UHF/VHF terminal, it worked perfect for about 1 minute then lost all the signals and had no picture. Then I connected the antenna to a VCR first, and connected both the UHF/VHF and video output from the VCR to the TV, it worked all the time. I thought maybe the signal was weak, by turning on the VCR may increase the signal so I didn't pay that much attention. Yesterday it started getting very poor picture quality. I disconnected the video input it got no picture at all. With the video input connected, it doesn't make any difference with or without the UHF/VHF input connected and the picture quality is way low. By connecting only the VCR UHF/VHF output to another TV (this one is a 19" sony with no video input terminal), the picture is perfect. Anyone have any idea what cause this problem and how can I fix it? Thanks in advance.
"This small electronically tuned Sony (Sony KV-13TR14) has this problem:
After about a minute of power on, picture snaps to another (cable) channel for an indeterminate amount of time and then snaps back to the original channel where it operates okay for periods of time (a few seconds to a minute or so). This goes on for several minutes then usually stops and doesn't happen again until the set is turned off, etc.
The local cable company told me that this model Sony had "a bad 'board' grounding problem" or some similar 'grounding' flaw.
I wrote to Sony asking if they were aware of a manufacturing problem with this model and they replied no.
Of course its out of warranty and there's the judgment of taking to the repair store or just buying new.
I'd sure like to repair this myself and any help greatly appreciated."
"I have two Sony TVs that seem to have tuner problems.
The first one is a 13" TV about 4 years old. After about 1 hour of use, the VHF channels go away and all I get is a scanning type picture and a high pitched whine. The UHF and Video input still work. (I do not have cable.) Turning the set off for a while will fix the problem. Also, the TV has the problem faster when it is hot out.
The next one is a 27" TV about 5 years old. When I first turn it on, it works fine for 1 minute or so. Then the VHF channels start to dissapper in the same way as the other TV. This starts at channel 9 (the top VHF station) and works its way down. The problem only affected channels 9 and 7 but not 4 and 2 go out too. After 5 or so minutes they are all back. UHF and Video input still work.
Would you suggest re-soldering the tuner modules for these TVs?"
"I'm wondering how easy it is to replace a tuner module for my 13" Sony. Repair shop said that it is a very expensive part and is very difficult to replace. I'm skeptical about the expense because the same shop replaced a tuner module on another tv I had and they listed the part as $5. If it's easy, any ideas about where I can find a replacement part?
A replacement tuner for a Sony 13" tv is a little expensive. I would suggest that you check the solder connections in the IF block before investing in a new tuner."
Caution: See the document: Troubleshooting and Repair of Consumer Electronic Equipment before attempting to repair or replace the tuner module. You *must* have proper soldering equipment and desoldering tools. Attempting to remove, solder, or replace the modules(s) without these *will* result in a mess and a very expensive bill when you finally take your TV to a professional.
Someone brought me a TV to look at. After a little prodding, it was learned that he had lent it to a friend and it died after six months or so. The 'friend' then attempted to replace the tuner module based on the description on a refused estimate from a TV service shop. He did not have proper soldering equipment - perhaps only a Weller 100W soldering gun. Needless to say, the TV did not work - nearly every pad on the PC board under the tuner had been destroyed. I had to run wires from the pins on the tuner to the their destinations on the mainboard. It was not fun. Luckly, no permanent damage was done but it could have easily been a lot worse.
You need to remove the two metal boxes (if there are two - one is the tuner and the other is the IF). On some sets like the 13 inch models, these are readily accessible once the rear cover is removed. On some 19" sets, the pins that need to be desoldered to remove the modules are partially blocked by the plastic bottom frame that holds the mainboard.
Once these are pulled, snap off the *bottom* shield of each and go over all solder connections - both through-hole and surface mount. You may be able to pinpoint some hairline cracks. The pins that go to the mainboard on the tuner and a coil on the IF module seems to be popular locations for problems. Also check the solder connections to the metal case shield and the fingers that need to make contact when the cover is snapped in place.
Don't touch any of the top-side components. Take care not to introduce any solder bridges or overheat anything. However, you may need more than a 15 watt iron to adequately heat some of the (shield) connections.
(From: Davetech (dnesbitt4@ vcom.is.net).)
If that is the one with an IF (VIF?) module beside the tuner, shoot some freeze spray into the module while it is playing. I had a Sony last week that turned out to have a bad solder joint in that module, and freezing it pinpointed it. It too, was "searching" through the channel.
(From: Gary Klechowitz (firstname.lastname@example.org).)
On Sony TV/monitors of the early 90s there were problems with solder connections in the AGC module. This module was a solder-on board enclosed in a metal box very much like the tunner. There were tunable coils inside and one or two of the legs from the coils would crack free from the circuit. This caused a gray screen effect but also caused the audio to drop out as well. This may be a similar problem. Look for any delay line modules. They are in small plastic cases sometimes orange colored and solder edgewise onto the main board. Inspect the solder connections there as well. If I remember right there was a delay line that had three legs and one of the solder connections would crack and you loose things like low level B & W. That would cause your problem.
(From: Jeff Rigby (email@example.com).)
If a sound and picture problem then look for bad connections in the tuner and the IF module. The IF module generally has bad connections at the pin connections for the Coils (IF, AFT, Disc). The tuner has bad grounds on the outer edge of the tuner board. This problem is generally temperature related=> it will work when cold or hot but in one condition or another will give problems.
As a check, with the back off and the set operating lightly tap the IF can and the tuner and see if the picture or sound changes.
Sound *only* problems are usually due to surface mount caps on the MPX decoder board.
Video only problems are a surface mount capitor problem in the comb filter board.
Both of the above are temperature related and usually get better as they heat up.
(From: Tom Cat (firstname.lastname@example.org).)
Remove IF 450, solder connections around AFT coil... and any other connection that looks bad... (very common problem).
(From: Mr. Caldwell (email@example.com).)
Open the IF assembly and resolder the coils, tuner should not need resoldering but if the problem persists you can resolder the ground connection in it if it does.
(From: Brian Leeman (firstname.lastname@example.org).)
I have run into a few of these...
In every case it has been due to one of the grounding "fan" leads that runs from the PCB to the metal case having a cold joint.
It has always been the lead that fastens to the top of the case directly to the left of the AGC trimmer (looking at the trace side).
These problems are gravy for techs, but it is a shame how poorly Sony executes the manufacture of their consumer electronics. Talk about mass produced junk...
Sorry for the rant, but if you work on this stuff, you have to agree!!
(From: Mister M. (email@example.com).)
You should start by checking for these symptoms. If the signal goes to snow then tap on the tuner to see if the signal returns. If it does then proceed to pull the tuner out and pop the shield to solder all grounds around the perimeter of the tuner. (being very careful with the solder splashing). If your signal seems to drift out and come back not snow but a smeared picture or a detuned like symptom then pull out you IF201 if block pop the shield and look for a AFT coil. Resolder and your back in business.
(From: Viawest (firstname.lastname@example.org).)
Invariably, the Sony KV-13TR14 and most of the ones near it are famous, and plaqued with bad solder joints. be very careful not to cause any solder bridges when resoldering the pc board. you must remove the shields from the tuner assembly to accomplish this repair. By the way, check the rest of the board *before* tearing your tuner apart. Sometimes it is a bad spot other than in the tuner itself - usaually the power supply.
(From: Raymond Carlsen (email@example.com).)
It sounds like you're describing the classic "tuner with bad solder connections". You'll have to remove the tuner and pop the covers. Resolder all the grounds around the outside of the little PC board. Also solder the ground tabs where the metal can pokes through and grounds the foil in half a dozen spots around the middle of the board. Look at the top side of the board to see where the metal goes through the PC. Work carefully! Don't get any solder "bridges" in there. Use a large enough (and hot enough) iron that will fully heat the connections without having to heat them for too long a time, but not so large a tip that will cause bridging. Re-install the tuner and pull the little can next to it. The PC connections that run from the board to the chassis need to be gone over. Resolder any connections that look flaky. Re-install that sub-board and you're done. That should take care of it. I've never had to do one twice.
Well, thanks to all those that suggested that I look at the I.F. assembly for poor grounds and soldering.
I pulled the unit from the main board last night, removed the tin covers on both sides. On the side with the coils and chips in it, there wasn't much to be done, so I left that pretty much alone. The other side was mostly surface mounted stuff. I didn't see anything that was grossly under soldered. Several joints looked "cold". All I did was touch up as many ground connections as I could .. re-solder the cold looking ones, re-do the two chips. I also bent out the little tabs that are on the covers of both sides of the unit .. these tabs apparently make contact with ground spots on the unit. After all this I resoldered the unit back onto the main board .. crossed my fingers, plugged the set back in and powered it up.
Success! No matter what channel I tuned to, the set came on (with picture) instantly. I powered it down several times to let it cool down again, and tried the experiment over and over ... never a failure. So, this morning, before going to work, I put the cover back on the 13" Sony and its working as well as the day I got it (1991). I did note that this is the ONLY Sony that I've had problems with. It was assembled in Mexico (strike 1???), and the I.F. tuner was made in Korea (strike 2???). I wonder if other's have found "non-Japanese" made Sonys to have less than the expected reliability?
"At start-up, picture comes on OK, then goes dark - loud Crash-Boom sounds from set. After turning off - letting sit - on -- repeats -- several times, seems to stabilize, stay on, and function Ok. I'd appreciate any advice so I know if the repairman has a clue."This may be tuner/IF related but other bad connections could be involved.
(From: Mr. Caldwell (firstname.lastname@example.org).)
What should be done anyway:
If you do all of this you should not have much else to worry about with this TV.
"I bought a Sony TV (model KV-27TS27) in 1992 and had some problem with the tuner right after the warranty expired but fortunately my Visa card's extended warranty covered some of the repair cost. Now the sound is getting very noisy and I suspect the audio module is not working properly. The TV is not covered by any warranty and I'd like to take care of it myself. I wonder if any one out there knows where I can order an audio module for my Sony TV."(From: Mr. Caldwell (email@example.com).)
The MPX 'IC' is a custom mini ceramic PCB with components masked onto it. It is easy to spot and as it is a DIP but you can see the components on the 1" x 1" ceramic 'board'. Capacitors on this board leak and cause a failure in the audio. It will do all sorts of weirdness and then fail.
Call Sony and politely gripe.
(From: John D. Carder (firstname.lastname@example.org).)
I buy the Sony SBX1637 MTS module from Matt Electronics for about $7 compared to Sony's price of $68! I have never had a repeat failure yet.
Defective IC on audio pcb. Little green part with tiny caps on it smack in the middle of the board with the a/v jacks on it. It's a ceramic PCB, about 1" square and it will have corrosion because the capacitors start leaking.
"I have a SONY KV-A2522U (U.K.) TV. About every hour or so it gives out, through the R. hand speaker, a very loud thunder like noise. (and just as loud) Even when the volume is set low? If I tap the set with my hand the noise stops. Telling me it's a loose connection?"(From: Steven Turner (email@example.com).)
Very common fault this. Locate the Metal heat sink running front to back resolder all the IC pins on the heat sink. That will fix it.
A few months ago someone gave me a Sony 27" KVE2911d television, which was repaired by Sony about 8 months ago. The set came up ok with sound and stereo LEDs but no picture at all. After warming up about 15 minutes the picture returned and stayed until switching off.
I talked to a Sony technician about this case and told him the set was already repaired by them 8 months ago for a lot of money and asked for help. While I think the Sony service is very poor by luck this time he told me about the bad solder connections from the tuner and IF boards.
I was very happy with this information and started taking off the cover for a check! But bad luck! Sony already had resoldered every connection of the tuner and IF boards. After a long time trying to locate the problem (only 15 minutes a day to measure!), I found out the problem was on the small CRT board located on the neck of the CRT. I resoldered the entire crt board (10 minutes of work) and the set has been OK since then.
(From: Mr. Caldwell (firstname.lastname@example.org).)
Call Sony Customer Service and explain the problem to them and see if they may cover parts. It's more than likely the tuner and while it can be resoldered and repaired in most cases you can do nothing wrong by asking Sony to cover some of the costs. A 3 year TV isn't that old.
Call Sony and see if they'll pay for the parts and then call a Sony service center and get an estimate and THEN tell them you've got authorization for the part from Sony. ;-)
Lately I caused myself a lot of grief quite innocently. I thought it might stop a problem before it happens to share this:
On a Sony KV-27S15 I needed to replace the tuner. The tuner is on the "A Board". Looks easy enough to get out but, one end of the board won't clear a metal frame that runs across the center of the main PCB. It's only a small part of the frame and was easily bent out of the way. Unknown to me, bending the frame caused the "solder land" that's under the frame where I bent it, to twist and cause an open connection all around the land. After replacing the tuner and the "A Board" I plugged the unit up, turned it on and POW, the power supply and the horizontal output were all bad.
After a day of troubleshooting I found that the crack had opened the only ground reference for the "feed back" loop of the transformer in the power supply (pin 12 of T603). The power supply lost it's ability to regulate and it ran at "full throttle".
What an embarrassment for me as this was an in-home tuner replacement and now I "Blew up the set". Anyway, everything is okay and the customer understood when I explained all this to them. It was one of those hard lessons that I thought some of you could appreciate and might avoid yourselves.
BTW, the tuner was bad like the tuners in the JVC's, where it intermittently looses the tuning but it's not a physical (connection) or thermal problem. My guess was the PLL IC was checking out. Until now, this model was free of any tuner problems for me.
I thought you should know about the service bulletin #203R3. This covers a lot of different models. It shows where to solder the grounds and they have a new cover to replace the original one for the tuner. Also, many of these and similar models have sound problems these can be repaired many times by replacing the SBX1637-11 module. The Sony part #8-746-371-20.
Also see the section: Noisy Audio.
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