Tech Help Hitachi, 65SWX20B

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My tv shut off last night. I finally got it to power up and stay up
with the sound just no pic. I figured out that when I unplug the 5 pin
connector that leads from the red light tube from the power board the
board will come on and stay up. If I try to plug it back in it will
give off a snap, small spark and shut the tv off.. The connector has 5
wires, one pink and four brown. With my meter I can put the pos on the
pink and go alone three of the browns and get 250V. On one of the
browns there is no power. Any ideas or tests I can do.. Any help will
be appreciated.

 

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If there are heatsinks on the CRT boards look to see whether the have a
three terminal device on them or an IC. If ICs it is likely that one of
them is shorted. To determine which one each CRT board needs to be
disconnected individually to find out which one.

If the snap you mentioned was from anode cap leakage you would notice
if you had disconnected the grounds, you would get zapped. It is very
unlikely to be able to disconnect all of the grounds easily, they are
redundant. If the snap was from focus voltage, well you did not
disconnect that, it usually goes right from the FCB to the socket
itself, doesn't even touch the PC board.

Sometimes ICs make a sound when they blow open, and do sound like an
arc. Therefore the first thing I would do is to physically inspect the
ICs for blow holes. This would be the quickest way to the problem. See
one, remove it and the set should run with the other two colors only.
At times they blow apart so you can't read the part number, but then
the other two do have the number, such as TDA6111Q, something like
that. Common problem if they use them.

Another possibility is that what you disconnected was the G2 supply,
but I am pretty sure that is a soft supply in those sets, so it can't
make a pop or snap. If that's the case, your meter is what loads it
down to 250V, because G2 is usually about 400V, but a meter loads it.
You wouldn't have that though, usually that will be a wire coming to a
one or two prong plug to the CRT socket board. It would not usually
come from the power board, it would come from the FCB (thingy with
either three or six controls on it).

Also, I seriously doubt whether a short on either focus or G2 would
cause the set to shutdown.

I just checked the database and there are no records for that model, is
it pretty new ? Or did you type it wrong ?

If it's really new are the CRTs still in warranty ? If so you shouldn't
be in there. If you screw anything up they might deny the warranty
claim. Because there is always a slight possibility that the CRT is
shorted. I would much rather pay someone just the labor to change a CRT
than to foot the whole bill.

Anyway, at this point, if you see TDA 6111 or 8351 on the devices on
the heatsinks, be very suspicious of them. Best I can do with the info
you provided.

JURB

 

[[email protected]]

I have attatched a pic of the power board that the 5 pin connector
plugs into. . The tv is about 3 years old. Just thought showing a
pic of the board might give a little more insight.

 

[[email protected]]

This is a pic of the area the connector plugs into. You mentioned a
shock in the other post. Last night when I had the board unplugged and
out I touched it on the bottom at a certain stop and it give me a
pretty good shock, and if I remember right that spot was right around
the plug area.

I have attatched a pic of the power board that the 5 pin connector
plugs into. . The tv is about 3 years old. Just thought showing a
pic of the board might give a little more insight.

If there are heatsinks on the CRT boards look to see whether the have a
three terminal device on them or an IC. If ICs it is likely that one of
them is shorted. To determine which one each CRT board needs to be
disconnected individually to find out which one.

If the snap you mentioned was from anode cap leakage you would notice
if you had disconnected the grounds, you would get zapped. It is very
unlikely to be able to disconnect all of the grounds easily, they are
redundant. If the snap was from focus voltage, well you did not
disconnect that, it usually goes right from the FCB to the socket
itself, doesn't even touch the PC board.

Sometimes ICs make a sound when they blow open, and do sound like an
arc. Therefore the first thing I would do is to physically inspect the
ICs for blow holes. This would be the quickest way to the problem. See
one, remove it and the set should run with the other two colors only.
At times they blow apart so you can't read the part number, but then
the other two do have the number, such as TDA6111Q, something like
that. Common problem if they use them.

Another possibility is that what you disconnected was the G2 supply,
but I am pretty sure that is a soft supply in those sets, so it can't
make a pop or snap. If that's the case, your meter is what loads it
down to 250V, because G2 is usually about 400V, but a meter loads it.
You wouldn't have that though, usually that will be a wire coming to a
one or two prong plug to the CRT socket board. It would not usually
come from the power board, it would come from the FCB (thingy with
either three or six controls on it).

Also, I seriously doubt whether a short on either focus or G2 would
cause the set to shutdown.

I just checked the database and there are no records for that model, is
it pretty new ? Or did you type it wrong ?

If it's really new are the CRTs still in warranty ? If so you shouldn't
be in there. If you screw anything up they might deny the warranty
claim. Because there is always a slight possibility that the CRT is
shorted. I would much rather pay someone just the labor to change a CRT
than to foot the whole bill.

Anyway, at this point, if you see TDA 6111 or 8351 on the devices on
the heatsinks, be very suspicious of them. Best I can do with the info
you provided.

JURB

 

[Meat Plow]

I have attatched a pic of the power board that the 5 pin connector
plugs into. . The tv is about 3 years old. Just thought showing a
pic of the board might give a little more insight.

Looks like something burnt up by the fuse.

 

[[email protected]]

You are right the board was hit by lightning a couple of months back.
It would not come on. I changed the part number X901 and it has been
working since, until now at least. One more note, I mentioned a shock
earlier, with the board unplugged. I took my meter and the tall brown
cap next to the 5 pin connector, has 150V coming from it. Please
excuse my not knowing much terminology about tv parts. I am trying to
learn and describe the problem and parts as best I can. I work on
pinball machines but a tv is a different animal.. Again, thanks for
all the help.

I have attatched a pic of the power board that the 5 pin connector
plugs into. . The tv is about 3 years old. Just thought showing a
pic of the board might give a little more insight.

Looks like something burnt up by the fuse.

 

[Meat Plow]

You are right the board was hit by lightning a couple of months back.
It would not come on. I changed the part number X901 and it has been
working since, until now at least. One more note, I mentioned a shock
earlier, with the board unplugged. I took my meter and the tall brown
cap next to the 5 pin connector, has 150V coming from it. Please
excuse my not knowing much terminology about tv parts. I am trying to
learn and describe the problem and parts as best I can. I work on
pinball machines but a tv is a different animal.. Again, thanks for
all the help.

I don't think getting shocked by a cap on the smps board is an indicator
of anything other than the supply is making 150 volts. In a case of
a circuit or component being stressed by a surge then subsequently failing
after a period of time, there are many variables. One can't say "well I've
seen other sets get hit by lightning and component xxx usually fails". You
need some kind of a diagnostic flow chart and methods to test and verify
components then move on to the next item. For many things I had this
stored in my head. Most factory service literature has this too. Your next
step may be acquiring a service manual unless you get lucky enough here.

I have attatched a pic of the power board that the 5 pin connector
plugs into. . The tv is about 3 years old. Just thought showing a
pic of the board might give a little more insight.

Looks like something burnt up by the fuse.

 

[Dartattack]

You are right the board was hit by lightning a couple of months back.
It would not come on. I changed the part number X901 and it has been
working since, until now at least. One more note, I mentioned a shock
earlier, with the board unplugged. I took my meter and the tall brown
cap next to the 5 pin connector, has 150V coming from it. Please
excuse my not knowing much terminology about tv parts. I am trying to
learn and describe the problem and parts as best I can. I work on
pinball machines but a tv is a different animal.. Again, thanks for
all the help.



Meat Plow wrote:-
On Tue, 02 Jan 2007 06:59:01 -0800, jmacross Has Frothed:
-
'[image
http://aycu02.webshots.com/image/6921/2000865101435510510_rs.jpg]
(http://allyoucanupload.webshots.com/v/2000865101435510510)

I have attatched a pic of the power board that the 5 pin connector
plugs into. . The tv is about 3 years old. Just thought showing a
pic of the board might give a little more insight.-

Looks like something burnt up by the fuse.-

It also looks as if the elecrolytic cap is bulging, the one on the lef
above the burnt looking area.
Gre

 

[[email protected]]

Well, it evidently took a hit when the board went out the first time.
It is giving me a reading of 18.4 V on the meter, is this normal? The
board is completely unhooked from the tv, should there still be any
power showing anywhere on the board?

You are right the board was hit by lightning a couple of months back.
It would not come on. I changed the part number X901 and it has been
working since, until now at least. One more note, I mentioned a shock
earlier, with the board unplugged. I took my meter and the tall brown
cap next to the 5 pin connector, has 150V coming from it. Please
excuse my not knowing much terminology about tv parts. I am trying to
learn and describe the problem and parts as best I can. I work on
pinball machines but a tv is a different animal.. Again, thanks for
all the help.



Meat Plow wrote:-
On Tue, 02 Jan 2007 06:59:01 -0800, jmacross Has Frothed:
-
'[image:
http://aycu02.webshots.com/image/6921/2000865101435510510_rs.jpg]'
(http://allyoucanupload.webshots.com/v/2000865101435510510)

I have attatched a pic of the power board that the 5 pin connector
plugs into. . The tv is about 3 years old. Just thought showing a
pic of the board might give a little more insight.-

Looks like something burnt up by the fuse.-

It also looks as if the elecrolytic cap is bulging, the one on the left
above the burnt looking area.
Greg

 

[[email protected]]

This is so obviously lightning or a power surge as evidenced by the
lower left corner of the pic. The black disk shaped component is
probably an MOV, like used in surge protectors.

This could mean big problems. What people do not understand is the the
EMP caused by lightning can put thousands of volts across a few feet of
wire. This wreaks havoc on semiconductor devices.

It is most likely the MOV is at least no longer effective. And it was
probably the pop. If you have other problems it might be a bit
difficult to fix them all. The set might fire up, but in such a case it
might pose an insidious shock hazard.

If you get it running you need to do something for safety. Afteer this
happens, before just hooking it back up, you need to do a live line
leakage check. Without proper tools, you turn it on and take something
and stick it in an electrical socket, touch every ground on the outside
of the TV as possible, this includes the antenna, the vid ins, all of
it. Don't go to the signal lines, just the grounds. Then take and do it
from the other "blade" of the plug.

This is called a ground fault and if you got one, everything you hook
up to that TV will become a shock hazard.

Unlike video games and other things, TVs can become a hazard alot
easier. Power supply requirements and a widely fluctuating load have
spurned them on to develop these super high efficiency power supplies,
and there may be other paths between hot and cold ground. If any of
them are shorted you could have an insidious, and possibly deadly
fault.

JURB

 

[[email protected]]

Thanks for the advice, I have ordered a new power supply board.
Hopefully get it tomorrow. I will hook that up and see what I got..