TV REPAIR

[©anadian Ponder]

Hello,

I don't want to spend too much time on this repair so can someone give
me a quick step through on what to check for.

Mitsubishi 35" CRT TV that won't turn on but hear the relay clicking.

I was thinking the horizontal high voltage transistor or the vertical
transistor.

Any other suggestions would be greatly appreciated.

Thanks !!

 

[[email protected]]

Hello,

I don't want to spend too much time on this repair so can someone give
me a quick step through on what to check for.

Mitsubishi 35" CRT TV that won't turn on but hear the relay clicking.

I was thinking the horizontal high voltage transistor or the vertical
transistor.

Any other suggestions would be greatly appreciated.

Thanks !!

Any other suggestions would be greatly appreciated. <------------

Yes, get it to a technician who knows how to troubleshoot failures.

 

[Dave]

Hello,

I don't want to spend too much time on this repair so can someone give me
a quick step through on what to check for.

Mitsubishi 35" CRT TV that won't turn on but hear the relay clicking.

I was thinking the horizontal high voltage transistor or the vertical
transistor.

Any other suggestions would be greatly appreciated.

No offense, but if your post indicates your level of troubleshooting
expertise, you are reduced to one of two possible choices:

1. Throw the set in the trash and buy another one or
2. Bring the set to a qualified repair shop.

There are several hundred components in that television, dozens of which
could cause the symptom you describe.

Actually, now that I think of it I guess you have a third choice:

3. Randomly replace expensive components until you exceed the value of a
new television or the frustration drives you batshit. I call this the
"guess 'n check" method; it's very expensive and time-consuming but some
people swear by it. ;-)

Dave

 

[Guest]

No offense, but if your post indicates your level of troubleshooting
expertise, you are reduced to one of two possible choices:

1. Throw the set in the trash and buy another one or
2. Bring the set to a qualified repair shop.

There are several hundred components in that television, dozens of which
could cause the symptom you describe.

Actually, now that I think of it I guess you have a third choice:

3. Randomly replace expensive components until you exceed the value of a
new television or the frustration drives you batshit. I call this the
"guess 'n check" method; it's very expensive and time-consuming but some
people swear by it. ;-)

Dave

I fixed televisions in my earlier days and I can count on one hand
the components that usually go bad.

I haven't repaired in over 10 years so I thought the technology may have
changed a bit.

One thing that hasn't changed are BITTER techs who did not get out of
the repair business when they should of and are now taking it out on others.

This is an electronics repair NG isn't it ???

 

[Dave]

wrote in message news:[email protected]...

I fixed televisions in my earlier days and I can count on one hand
the components that usually go bad.

I haven't repaired in over 10 years so I thought the technology may have
changed a bit.

One thing that hasn't changed are BITTER techs who did not get out of the
repair business when they should of and are now taking it out on others.

This is an electronics repair NG isn't it ???

As I noted, no offense to you. All I had to go on was your post, which
contained a couple of seemingly wild guesses as to what the problem might be
with no description of any supporting troubleshooting you may have done to
arrive at these rather specific conclusions. Nor any description of your
past experience or qualifications to arrive at these conclusions. There are
A LOT of people that, quite frankly, post stupid poorly thought-out
questions; these folks by and large have no business opening up a TV and
having the remotest shred of faith that they could potentially repair it.
Oftentimes what they HAVE done as a "fix" or a "workaround" has exacerbated
the problem and increased the cost of repair severalfold.

Most tV's for the past TWENTY years have varying protection schemes which
keep the set from fully powering up when the set's microprocessor detects
any of a myriad of faults. Incorrect voltages, excessive ripple, ground
shorts, temperatures, all sorts of things _COULD_ keep the set from starting
up. Or bad sensors for any of the above. If you think it's the HOT, why
don't you spend 10 minutes and pull it and see if the set stays powered up?
THEN we'd have a starting point. IF it's a bad HOT, then it's likely that
it was caused by, or its' failure caused, other component failures. It's
extremely rare to find the blackened component, replace it, and everything's
good to go.

This group tends to be very generous with their time and expertise _IF_ you
can demonstate that there's a hope in hell you have any chance of success.
Such things as a description of any troubleshooting you may have done prior
to posting goes a long way here...

Dave

 

[©anadian Ponder]

Dave wrote:
It's

extremely rare to find the blackened component, replace it, and everything's
good to go.

I did fix my brother's 32" CRT 2 months ago. The Horizontal Output
transistor was shorted on all leads.

Replaced just the one component and fixed the problem. I though the
flyback would be gone as to cause this failure but NOT the case.

Sometimes components get too hot and fail. Bad engineering !!

 

[©anadian Ponder]

In my opinion the TOP 5 reasons why a CRT TV fail
in no particular order.

blown fuse
bad ripple cap
horizontal o/p transistor
vertical o/p transistor
flyback

 

[AJ]

Start with the obvious failures, then begin testing all the electrolytic
caps with a good ESR meter. Obtain a good service manual with appropiate
voltage measurements and waveforms. Then have at it, hasn't changed that
much in the past decade. May want to ring the LOPT and Yoke coils to rule
out those items. Try a lamp in series with the collector of the H-Output.
Having serviced these devices before, the rest should come natural. Cheers

 

[James Sweet]

I fixed televisions in my earlier days and I can count on one hand
the components that usually go bad.

I haven't repaired in over 10 years so I thought the technology may have
changed a bit.

One thing that hasn't changed are BITTER techs who did not get out of the
repair business when they should of and are now taking it out on others.

This is an electronics repair NG isn't it ???

It's always good to state those sorts of things up front, a lot of people
who post here really truly shouldn't be poking around inside a TV, when it
doubt, assume the latter.

Amazingly enough, the design of CRT televisions hasn't really changed much
in the last 25 years, they've gained more features, but the basics are all
pretty much the same.

 

[James Sweet]

Dave wrote:
It's


I did fix my brother's 32" CRT 2 months ago. The Horizontal Output
transistor was shorted on all leads.

Replaced just the one component and fixed the problem. I though the
flyback would be gone as to cause this failure but NOT the case.

Sometimes components get too hot and fail. Bad engineering !!

HOTs are one of those parts that seem to occasionally just fail for no
specific reason. Often it's a cracked solder joint that takes them out, but
I've repaired many TVs and monitors over the years by just replacing the
HOT.

 

[James Sweet]

In my opinion the TOP 5 reasons why a CRT TV fail
in no particular order.

blown fuse
bad ripple cap
horizontal o/p transistor
vertical o/p transistor
flyback

If there's a blown fuse, there's another problem 99% of the time.

I'd put cracked solder joints on the top of that list, of course those often
toast other parts.

 

[[email protected]]

Interesting. My 32" Toshiba is getting half-inch horizontal white
(dot) lines on its very top even after its warmed up (when cold, its
about 2 inchs). As many people pointed out that my TV is on its way
for retire. Should this be the case of so call 'horizontal o/p
transistor' problem ?
Any suggestions (or links) of how to fix it ? I know how danger can it
be while fixing a TV since it is high-volt stuff and just kind of
curiosity.

 

[b]

In my opinion the TOP 5 reasons why a CRT TV fail
in no particular order.

blown fuse
bad ripple cap
horizontal o/p transistor
vertical o/p transistor
flyback

a blown fuse is not the cause of the failure.
i haven't seen that many with a 'bad ripple cap' (mains filter) -
usually the small ones die first.

My list is more like:
1. bad solder joints
2. dried or high ESR caps in power and line stages
3. shorted mains rectifier diodes or blown psu often due to surges or
the PTC.
4. bad vertical /frame chip, often with its feed resistor, and related
caps
5. bad horizontal transistor and related hi volt caps
6. Bad line transformer (flyback)
7. Bad RGB chip
8. H-k shorts etc and other tube problems
9. no line drive - poor soldering or bad parts
10. bad EEPROM

 

[JANA]

This can be any number of many types of parts. Proper troubleshooting is
required. This will take the proper training, experience, tools, and having
the service information.

As for servicing your TV set, take it over to a service centre and let them
do a proper and safe job.

--

JANA
_____


Interesting. My 32" Toshiba is getting half-inch horizontal white
(dot) lines on its very top even after its warmed up (when cold, its
about 2 inchs). As many people pointed out that my TV is on its way
for retire. Should this be the case of so call 'horizontal o/p
transistor' problem ?
Any suggestions (or links) of how to fix it ? I know how danger can it
be while fixing a TV since it is high-volt stuff and just kind of
curiosity.