Sony TV Tuner and IF Solder Connection Problems


[Document Version: 1.27] [Last Updated: 05/25/1998]

Chapter 1) About the Author & Copyright

Sony TV Tuner and IF Solder Connection Problems

Author: Samuel M. Goldwasser
Corrections/suggestions: | Email

Copyright (c) 1994, 1995, 1996, 1997, 1998
All Rights Reserved

Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied:

  1. This notice is included in its entirety at the beginning.
  2. There is no charge except to cover the costs of copying.

Chapter 2) Introduction

  2.1) Scope of this document

Problems with bad solder connections, mostly in and around the tuner and IF
boxes are very common with several series of late model Sony TVs.  The repairs
are straightforward though perhaps tedious and on some models, removing the
tuner and IF boxes from the mainboard can be real fun.

Some of the common symptoms include:

    * Picture turns to snow or shows other reception problems.
    * Inability to tune blocks of channels.
    * Channels change randomly as if TV doesn't like what you are watching.
    * Loss of picture - just raster and high pitched whine.
    * Noisy or muted sound, volume buttons have no effect.
    * Controls have no or unexpected affect (console or remote).

Note that many other manufacturer's TVs are also susceptible to similar
symptoms with similar causes.

The articles in this document have been compiled over the last few
months from postings on the USENET newsgroup

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

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.

Chapter 3) Solder Connection Problems and Solutions

  3.1) Symptoms of cracked solder connections

Here are some typical sets of symptoms resulting from bad solder connections
in and around the tuner of this series of late model TVs.  Most of these
problems are characterized by erratic behavior of one form or another.
However, total failure of reception is possible:

"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."

"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

"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?"

This may be an actual electronic problem but would still recommend doing
the resoldering first.

"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."

  3.2) General repair considerations

Caution: See the document: "Troubleshooting and Repair of Consumer Electronics 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.

  3.3) Descriptions of the solutions

Here are some of the responses - many from experienced techs who fix (too)
many of these sets:

(From: Davetech (dnesbitt4@

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

(From: Gary Klechowitz (

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 (

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

Both of the above are temperature related and usually get better as they
heat up.

(From: Tom Cat (

Remove IF 450, solder connections around AFT coil... and any other 
connection that looks bad...  (very common problem).

(From: Mr. Caldwell (

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

(From: Brian Leeman (

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. (

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 (

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 (

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. 

  3.4) Successes from non-techs

(From: Bill Somrak (

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?

Chapter 4) Miscellaneous Problems

  4.1) Erratic picture and sound

"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 (

What should be done anyway:

* Resolder all the TO220 package regulators on the main board.
* Resolder the Horizontal Output Transformer.
* Remove open and resolder the IF pack coils.
* Remove the power supply itself and resolder the output diodes.

There is a capacitor in the power supply that's caused some problems,
it's the 22V/27V line I think, a 1000uf@25v or 1000@50v. I've just been
replacing it with a 1000uf@50v.

If you do all of this you should not have much else to worry about
with this TV.

  4.2) Noisy audio

"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 (

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.

  4.3) Intermittent audio

"My Sony KV-32TS20 television (4 yrs. old) has developed an audio problem.  The
 stereo LED no longer lights ups and I get intermittent popping/crackling along
 with the audio.  I have tried switching between mono and stereo and the audio
 sounds the same in either mode (sounds like mono in both modes to me).  This
 set had the infamous Sony tuner solder joint problem in the past which was 
 resolved by resoldering the tuner to main ckt. board connections.  Now I
 resoldered the audio section solder joints on the main circuit board but the
 audio problem remains."

(From: Mr. Caldwell (

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.

  4.4) Periodic audio noise

"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 (

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.

  4.5) Intermittent picture

(From: John de Rooy (

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.

Chapter 5) Service Information, Costs, Reliability

  5.1) Getting out-of-warranty repairs

If you are not inclined to tackle these sorts of repairs for whatever reason,
you may still have recourse with Sony.  If pressed, they will often cover
at least part of the cost of the repair.

(From: Mr. Caldwell (

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. ;-)

  5.2) Warning about Sony tuner repair on certain models

(From: Gary Warner (

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.

  5.3) Sony service bulletins

(From: Lynn H. Blakely (

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.

Written by Samuel M. Goldwasser. | [mailto]. The most recent version is available on the WWW server [Copyright] [Disclaimer]