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Fixing Monitors and TV Sets

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MrAl

Well-Known Member
Most Helpful Member
Hi there,

One of my monitors went out a couple weeks ago and i took it
apart and could not find anything burnt out, and without a schematic
i had no way of trouble shooting it that well. I didnt want to pay
for a schematic because the monitor is old anyway.

I had a TV set (CRT) go out too a while back (few years or so) and
took that apart and spent 25 dollars for a schematic. I found that
the high voltage transistor was bad and replaced it with a custom
connection of series 400v transistors. I got a picture with that,
so i assumed it was really the HV transistor. I checked the price,
and it turned out to be around 25 dollars too. The thing is, i was
afraid to buy a new transistor because if there were other parts bad
that caused the transistor to blow out then a new transistor would
blow after a short time anyway, and besides the TV was fairly old
anyway.

So what i ended up doing in both cases is buying a new model.
Rather than put out the money for something that might not work
that much longer anyway i decided to apply that money to a new
model and at least have something that should last a while.

Anyone else ever have this kind of experience?
 
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I found many sites selling the schematic for my 32" Sony TV but found it for free and many people chatting about the same problem as mine.
I found 2 shorted transistors in the power supply, one shorted horizontal output transistor and a blown resistor.
I ordered the parts from the local Sony repair facility using part numbers on the schematic and on the blown parts and they sent the wrong parts. Customer service appologised and said that they do not have many parts and usually do not sell parts. They found the correct parts and sent them.

The heatsinks were STEEL not aluminum and the thermal grease was all dried up and useless (the TV was 8 yeras old). I replaced the parts and used new thermal grease and the TV worked! For 1 week then the same parts failed again.

I saw the local TV repairman and asked him to come and get it for free. He didn't want it.
I advertised on the internet and a guy took it and gave me $25.00.
My daughter gave me her big old Toshiba TV.

I will probably never buy a Sony TV again.
 
I found many sites selling the schematic for my 32" Sony TV but found it for free and many people chatting about the same problem as mine.
I found 2 shorted transistors in the power supply, one shorted horizontal output transistor and a blown resistor.
I ordered the parts from the local Sony repair facility using part numbers on the schematic and on the blown parts and they sent the wrong parts. Customer service appologised and said that they do not have many parts and usually do not sell parts. They found the correct parts and sent them.

The heatsinks were STEEL not aluminum and the thermal grease was all dried up and useless (the TV was 8 yeras old). I replaced the parts and used new thermal grease and the TV worked! For 1 week then the same parts failed again.

I saw the local TV repairman and asked him to come and get it for free. He didn't want it.
I advertised on the internet and a guy took it and gave me $25.00.
My daughter gave me her big old Toshiba TV.

I will probably never buy a Sony TV again.


Hi,

Geeze, very sorry to hear about that second failure. That's what i was
so afraid of when it came time to buy parts for the old sets. I wasnt sure
if i had all the parts that were bad nailed down so there was a chance
of losing my investment totally.

Interesting that you should mention Sony...because i had one of
their computer "monitors" (note the quotes he he) which all had
(or still have maybe) a thin line going across the center of the screen
to keep the background mask from resonating...well it blew out in
only one year! That was nasty too, because it cost me over 300 dollars
at the time. Their larger monitors had two lines across the center
to dampen the mask! Strange.
 
Sony almost went bankrupt because they were sued for their horrible anti-copy scheme and for the millions of laptop batteries they replaced because many caught on fire. Their patent on their Trinitron screen ran out and other companies were copying it for free. They spent a fortune on developing high definition plazma and LCD screens.
 
I had the 32" Sony Trin. My set went blank after 5 years of use. I threw it away. My Sony DVD player is also getting fickle about what DVD's it will play. Sony is not my favorite brand.
 
I will probably never buy a Sony TV again.

I've got a circa 20 year old 25in Sony KV-25XBR that I replaced the flyback on (and only the flyback, luckily) about six years ago, and it's still functioning as our main family room set. The raster sags in on both sides when cold, about an inch or so, but after a couple mins of warm-up the problem goes away.

It was top of the line back then (has RGB inputs, which TVs rarely had), so perhaps it's a little better quality than their normal consumer grade stuff...
 
My Sony TV had two 1kV capacitors in series instead of one 2kV capacitor.
The TV was assembled in Mexico.
 
The heatsinks were STEEL not aluminum and the thermal grease was all dried up and useless (the TV was 8 yeras old). I replaced the parts and used new thermal grease and the TV worked! For 1 week then the same parts failed again.

Sorry, but you attempted a repair, cured the symptom, but NOT the cause - then complain when it failed in the same fashion again.

You didn't repair it properly, that was your problem.

The fault was most probably dry joints on the line driver transformer, this causes the LOPT transistor not to be switched ON fully, so it overheats and goes S/C. This is a common fault on almost all makes of TV.

Not buying Sony again is obviously your choice, but the fact remains, Sony are still one of the most reliable sets you can buy.
 
Sorry, but you attempted a repair, cured the symptom, but NOT the cause - then complain when it failed in the same fashion again.

You didn't repair it properly, that was your problem.

The fault was most probably dry joints on the line driver transformer, this causes the LOPT transistor not to be switched ON fully, so it overheats and goes S/C. This is a common fault on almost all makes of TV.

Not buying Sony again is obviously your choice, but the fact remains, Sony are still one of the most reliable sets you can buy.

Nigal. No dispute of the repair or a Sony CRT. But the Sony Plasmas at the college within 2 years we seen the sets fail one by one. Out of the three. I have two still going. The third went so badly it couldn't be cost effectively repaired.
 
Nigal. No dispute of the repair or a Sony CRT. But the Sony Plasmas at the college within 2 years we seen the sets fail one by one. Out of the three. I have two still going. The third went so badly it couldn't be cost effectively repaired.

Plasma have been pretty unreliable, not just Sony, but all makes - most failures on them are the PDP (Plasma Display Panel) - a part which Sony bought from Fujitsu. Another common failing in the Sony ones is the PSU, another part they bought from a third party (and can't supply a circuit or spares for) - the Sony bits in them seem pretty reliable :D

Perhaps Sony were wise to drop Plasma and concentrate on LCD? - as many others have since.

Our LCD sales outweigh Plasma sales by hundreds to one, yet we've written off more Plasma's than LCD's - and the LCD's have mainly been physical damage - including been struck by a pool cue!.

BTW - I have a Plasma - I got it free when the owner bought an LCD to replace it, and wanted it disposing off.
 
I am blind in one eye now because of cataracts. I got the other eye fixed (a nice clear new lens inside my eye) about a month ago and get my blind eye fixed in 2 days.
Then I might buy an LCD high-definition large screen TV.
 
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I am blind in one eye now because of cataracts. I got the other eye fixed (a nice clear new lens inside my eye) about a month ago and get my blind eye fixed in 2 days.

Good luck with that.

Then I might buy an LCD high-definition large screen TV.

Bear in mind to get any benefit from HD you need to view from quite close, closer than double the screen size - so 80 inches away from a 40 inch TV.
 
Bear in mind to get any benefit from HD you need to view from quite close, closer than double the screen size - so 80 inches away from a 40 inch TV.

"Visual acuity is often measured in cycles per degree (CPD), which measures an angular resolution, or how much an eye can differentiate one object from another in terms of visual angles. Resolution in CPD can be measured by bar charts of different numbers of white — black stripe cycles. For example, if each pattern is 1.75 cm wide and is placed at 1 m distance from the eye, it will subtend an angle of 1 degree, so the number of white — black bar pairs on the pattern will be a measure of the cycles per degree of that pattern. The highest such number that the eye can resolve as stripes, or distinguish from a gray block, is then the measurement of visual acuity of the eye.

For a human eye with excellent acuity, the maximum theoretical resolution would be 50 CPD (1.2 arcminute per line pair, or a 0.35 mm line pair, at 1 m)."

Regular set = 525 lines, HD = twice as many?

To me HD looks sharper at whatever distance I'm seeing it from.
 
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With SD there's a minimum recommended viewing distance, usually about 2.5 times the screen size - this is so you can't see the lines on a CRT, or the digital artifacts from upscaling on an HD TV.

Basically this means you are too far away to see fine detail, so you need to be considerably closer to see the fine detail which is what HD is all about - unfortunately this means you should really view SD and HD from different distances :(
 
With SD there's a minimum recommended viewing distance, usually about 2.5 times the screen size - this is so you can't see the lines on a CRT, or the digital artifacts from upscaling on an HD TV.

Basically this means you are too far away to see fine detail, so you need to be considerably closer to see the fine detail which is what HD is all about - unfortunately this means you should really view SD and HD from different distances :(

This is good news for me; my wife wants to get HD. I don't.

We would have bought a 32" wide set (so it fits in the existing cabinet) and sat in our usual place 10' away, and wondered why it looked the same.
You might have just saved me >0.5 kilobuck!
 
This is good news for me; my wife wants to get HD. I don't.

We would have bought a 32" wide set (so it fits in the existing cabinet) and sat in our usual place 10' away, and wondered why it looked the same.
You might have just saved me >0.5 kilobuck!

As repairs get fewer and fewer, I'm spending more and more time fitting sets on walls etc.

If you're considering this (or anyone else), don't mount it too high - it wants to be at the line of your eyes when you're sat comfortably - if you mount it too high you have to look up to watch, and this gives you a sore neck.
 
Regular set = 525 lines, HD = twice as many?
Sort of. You are confusing the number of horizontal scanning lines (525 in North America) with the number of vertical visible resolution transistions on a screen from left to right. They called the resolution "lines" by mistake so it is confusing.

A VHS tape is only about 240 lines at good speed and only about 180 lines at slow speed. A good live transmission has about 330 lines. An old DVD is 540 lines and Blu-ray is better.

A high definition TV displays 1080 horizontal scanning lines. If it is 1080p then it has a left to right resolution of 960 lines (1920 pixels).

High definition has a wider screen than a regular TV so extra resolution lines are on the screen but do not increase the resolution.
So the best high-definition has a resolution that is 2 times better than regular live TV.
 
Sort of. You are confusing the number of horizontal scanning lines (525 in North America) with the number of vertical visible resolution transistions on a screen from left to right. They called the resolution "lines" by mistake so it is confusing.

A VHS tape is only about 240 lines at good speed and only about 180 lines at slow speed. A good live transmission has about 330 lines. An old DVD is 540 lines and Blu-ray is better.

Do you perhaps mean 440 lines for DVD?, you can't have more than 525, and it has to be considerably less than that. PAL DVD is 576 visible lines out of 625.

A high definition TV displays 1080 horizontal scanning lines. If it is 1080p then it has a left to right resolution of 960 lines (1920 pixels).

Lost me there?, how did you go from 960 lines to 1920 pixels?.

High definition has a wider screen than a regular TV so extra resolution lines are on the screen but do not increase the resolution.

Not on this side of the pond, SD TV has been widescreen for many, many years - North America lagged behind Europe greatly in that respect :D

So the best high-definition has a resolution that is 2 times better than regular live TV.

Actually more than four times greater, and that's for 625 line widescreen - it will be even more for 525 line 4:3 - it's the number of pixels that you compare.
 
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