A television question

[Ian Sutherland]

Hi folks, I have been given a Sony 21" Model KV-2184AS. will be ideal
for watching the cricket in the workshop. Supposed to have an
intermittent/uneconomical to repair fault. I watched the last couple
of 1 day finals (8 Hrs. plus) with no sign of a fault. Next switch on,
no sound, no pic. It had a snowy raster, & speaker hiss. Also on
screen display's functioned. Absolutely no sign of sound or pic or
sync. bars, nothing!!

Did this for next 5 or 6 switch on's, was about to take it down from
the wall bracket, switched on, & operation normal. (1 week later,
still functioning.)

When it was dysfunctional I gave it a couple of thumps, no effect.

Does anyone have a circuit diag. they could copy & post to me? I'm
in Adelaide, & happy to pay any costs involved.

To me it doesn't seem irrepairable, hopefully just tuner power
supply or something else as easy to diagnose.

My background is retired electronics tech, speciallizing in
industrial controls.

T.I.A Ian Sutherland.

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[James]

Hi folks, I have been given a Sony 21" Model KV-2184AS. will be ideal
for watching the cricket in the workshop. Supposed to have an
intermittent/uneconomical to repair fault. I watched the last couple
of 1 day finals (8 Hrs. plus) with no sign of a fault. Next switch on,
no sound, no pic. It had a snowy raster, & speaker hiss. Also on
screen display's functioned. Absolutely no sign of sound or pic or
sync. bars, nothing!!

Did this for next 5 or 6 switch on's, was about to take it down from
the wall bracket, switched on, & operation normal. (1 week later,
still functioning.)

When it was dysfunctional I gave it a couple of thumps, no effect.

Does anyone have a circuit diag. they could copy & post to me? I'm
in Adelaide, & happy to pay any costs involved.

To me it doesn't seem irrepairable, hopefully just tuner power
supply or something else as easy to diagnose.

My background is retired electronics tech, speciallizing in
industrial controls.

T.I.A Ian Sutherland.

To Email, remove the leading z

Being a Sony I'd say probably the tuner itself. Haven't worked on them for a
while now and can't recall that model precisely, but in a lot of the smaller
sony sets around the 10year old mark the tuners were bloody unreliable. If
your lucky it might be a generic get from WES for $30 job.

James

 

[Bob M]

Hi folks, I have been given a Sony 21" Model KV-2184AS. will be ideal
for watching the cricket in the workshop. Supposed to have an
intermittent/uneconomical to repair fault. I watched the last couple
of 1 day finals (8 Hrs. plus) with no sign of a fault. Next switch on,
no sound, no pic. It had a snowy raster, & speaker hiss. Also on
screen display's functioned. Absolutely no sign of sound or pic or
sync. bars, nothing!!

Did this for next 5 or 6 switch on's, was about to take it down from
the wall bracket, switched on, & operation normal. (1 week later,
still functioning.)

When it was dysfunctional I gave it a couple of thumps, no effect.

Does anyone have a circuit diag. they could copy & post to me? I'm
in Adelaide, & happy to pay any costs involved.

To me it doesn't seem irrepairable, hopefully just tuner power
supply or something else as easy to diagnose.

My background is retired electronics tech, speciallizing in
industrial controls.

T.I.A Ian Sutherland.

To Email, remove the leading z

Hi Ian,

Sounds like an intermittent antenna connection into the tuner. Follow
the signal feed into the tuner, looking for a cold/cracked solder
joint. I have to use a magnifying glass these days but be patient and
you will find it. Over the years, thermal stresses cause this fault
often. I am in the process of tracking down a similar issue on my Sony
32" TV. My problem is in the cabling connections that connect the
video output of the tuner to the main chassis (picture goes very dark
with only slight amount of red coming through). Been at it for a while
(a little vibration and the fault goes away) but I know I will
eventually find it.

Best of luck and happy hunting!

Cheers from Canada

Bob M.

 

[Rudolf Ladyzhenskii]

Resolder IF module and around the tuner.

Rudolf

 

[Ian Sutherland]

Hi folks thanks to those that replied, & cheer's to Bob in Canada.
I didn't want to do a blanket solder, but would have preferred to
have found the fault. That struck me as being too hard, looked at all
the solder joints on the main board & they looked O.K. Desoldered the
tuner module, removed the screen shields & boy what a mess. 43
inductors, 86 leads & about 50% were bad solder joints, particularly
cratering around the lead. Dozens of surface mount component's but
they all looked O.K. There were 2 resistors on the board & both had a
crack right around 1 lead, on 1 of them I could see the crack get
bigger & smaller as I moved the lead with tweezer's, this resistor was
on the B+ line.
Resoldered all leads except suface mount & reinstalled. Perfect pic. &
sound. Before the resolder, the set was running on a small indoor
antenna with a snowy pic, now, same antenna, no snow at all, must have
increased the sensitivity as well. I hope it's fixed, and thanks again
for the help.

While the main board is out, should I remove the I.F. module or let
sleeping dogs lie?
Cheer's, Ian Sutherland.

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