Philips model #32HFL5460S/27 no picture

I don't have experience with these flat panels (have worked on regular
tube sets for about 5 years), so I'm hoping for a little help. This
set powers on, and you briefly see the philips logo on screen but the
image is shaky, then after maybe one second, this display drops out
and all that's left is a dim blue screen. Haven't seen anything on the
web concerning problems with this set. Would this be a back light
inverter problem? Without a schematic, I'm sorta of lost on this. If
it may be the backlight, how do you go about troubleshooting before
replacing parts? Thanks for any help group.

 

[Arfa Daily]

<stokesbr@cox.net> wrote in message
news:764ac208-ccb3-42f3-8b22-25f8416f1e63@n7g2000yqb.googlegroups.com...

I don't have experience with these flat panels (have worked on regular
tube sets for about 5 years), so I'm hoping for a little help. This
set powers on, and you briefly see the philips logo on screen but the
image is shaky, then after maybe one second, this display drops out
and all that's left is a dim blue screen. Haven't seen anything on the
web concerning problems with this set. Would this be a back light
inverter problem? Without a schematic, I'm sorta of lost on this. If
it may be the backlight, how do you go about troubleshooting before
replacing parts? Thanks for any help group.

If the mainboard attempts to 'boot' (logo displays) but then it drops back
to a blue screen, I would feel inclined to be looking around the power
supply first. Just about all LCD TVs suffer from problems with bad
electrolytics on the power supply, and also bad joints on the dreadful
lead-free solder that's used now to build them. First, carefully examine all
of the electrolytics, but particularly the secondary side ones, and
especially any near or under heatsinks, for signs of their tops bulging. If
none immediately leap out at you as being faulty in this way, then run over
them all with an ESR meter. After that, examine the solder side of the board
very carefully under a strong light and with a powerful magnifying glass. Be
advised though that bad joints made with lead-free solder can be very
difficult to spot ...

Arfa

 

[William Sommerwerck]

...examine the solder side of the board very carefully under a
strong light and with a powerful magnifying glass. Be advised,
though, that bad joints made with lead-free solder can be very
difficult to spot...

If bad joints are hard to spot, why not just redo all of them with tin/lead
solder?

 

[IanM]

William Sommerwerck wrote:

...examine the solder side of the board very carefully under a
strong light and with a powerful magnifying glass. Be advised,
though, that bad joints made with lead-free solder can be very
difficult to spot...

If bad joints are hard to spot, why not just redo all of them with tin/lead
solder?
Because unless you remove better than 95% of the lead free solder the

resulting alloy is too far from the eutectic and vastly increases the
risk of a bad joint!
--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:

 

[Michael A. Terrell]

IanM wrote:

William Sommerwerck wrote:
...examine the solder side of the board very carefully under a
strong light and with a powerful magnifying glass. Be advised,
though, that bad joints made with lead-free solder can be very
difficult to spot...

If bad joints are hard to spot, why not just redo all of them with tin/lead
solder?
Because unless you remove better than 95% of the lead free solder the
resulting alloy is too far from the eutectic and vastly increases the
risk of a bad joint!

Not if you use 50/50 solder.

--
Greed is the root of all eBay.

 

[Arfa Daily]

"IanM" <look.in.my.sig@totally.invalid> wrote in message
news:hk2v20$2avb$1@energise.enta.net...

William Sommerwerck wrote:
...examine the solder side of the board very carefully under a
strong light and with a powerful magnifying glass. Be advised,
though, that bad joints made with lead-free solder can be very
difficult to spot...

If bad joints are hard to spot, why not just redo all of them with
tin/lead
solder?

Because unless you remove better than 95% of the lead free solder the
resulting alloy is too far from the eutectic and vastly increases the risk
of a bad joint!
--
Ian Malcolm.

Absolutely correct, quite aside from the fact that it is illegal for a
professional repairer in the EU to repair a post-June 2006 piece of
equipment that's built using lead-free, with anything other than lead-free.
As a professional repairer myself, I observe this, much as I hate doing so
and, without looking into the status and location of a poster too closely, I
would not recommend that he or she does any different.

Also, have you ever tried doing a successful blanket resolder on a complex
board that is covered in surface mount as well as conventional components?
On an average LCD power supply, there is probably better than 1000 joints
....

Arfa

 

[William Sommerwerck]

If bad joints are hard to spot, why not just redo all
of them with tin/lead solder?

Because unless you remove better than 95% of the
lead-free solder the resulting alloy is too far from the
eutectic and vastly increases the risk of a bad joint!

Absolutely correct, quite aside from the fact that it is illegal
for a professional repairer in the EU to repair a post-June 2006
piece of equipment that's built using lead-free, with anything
other than lead-free.

I suspected that.

As a professional repairer myself, I observe this, much as I hate
doing so and, without looking into the status and location of a
poster too closely, I would not recommend that he or she does
any different.

Also, have you ever tried doing a successful blanket resolder
on a complex board that is covered in surface mount as well
as conventional components? On an average LCD power supply,
there is probably better than 1000 joints.

I assumed we were talking about only the electrolytics.

I'm glad I have a big roll of eutectic lead solder. (Don't report me!
<grin&gt

 

[Arfa Daily]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:hk3v1o$qk2$1@news.eternal-september.org...

If bad joints are hard to spot, why not just redo all
of them with tin/lead solder?

Because unless you remove better than 95% of the
lead-free solder the resulting alloy is too far from the
eutectic and vastly increases the risk of a bad joint!

Absolutely correct, quite aside from the fact that it is illegal
for a professional repairer in the EU to repair a post-June 2006
piece of equipment that's built using lead-free, with anything
other than lead-free.

I suspected that.


As a professional repairer myself, I observe this, much as I hate
doing so and, without looking into the status and location of a
poster too closely, I would not recommend that he or she does
any different.

Also, have you ever tried doing a successful blanket resolder
on a complex board that is covered in surface mount as well
as conventional components? On an average LCD power supply,
there is probably better than 1000 joints.

I assumed we were talking about only the electrolytics.

I'm glad I have a big roll of eutectic lead solder. (Don't report me!
grin&gt

Would that it was just bad joints on electrolytics we were talking about ...

Arfa

 

On Jan 31, 1:27 pm, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:

"William Sommerwerck" <grizzledgee...@comcast.net> wrote in message

news:hk3v1o$qk2$1@news.eternal-september.org...





If bad joints are hard to spot, why not just redo all
of them with tin/lead solder?

Because unless you remove better than 95% of the
lead-free solder the resulting alloy is too far from the
eutectic and vastly increases the risk of a bad joint!

Absolutely correct, quite aside from the fact that it is illegal
for a professional repairer in the EU to repair a post-June 2006
piece of equipment that's built using lead-free, with anything
other than lead-free.

I suspected that.

As a professional repairer myself, I observe this, much as I hate
doing so and, without looking into the status and location of a
poster too closely, I would not recommend that he or she does
any different.

Also, have you ever tried doing a successful blanket resolder
on a complex board that is covered in surface mount as well
as conventional components? On an average LCD power supply,
there is probably better than 1000 joints.

I assumed we were talking about only the electrolytics.

I'm glad I have a big roll of eutectic lead solder. (Don't report me!
grin&gt

Would that it was just bad joints on electrolytics we were talking about ....

Arfa- Hide quoted text -

- Show quoted text -

Thanks to all for the advice. Sorry for the late reply (been working
night shift). I have looked over the power supply (checked some of the
components) since the set does startup, but immediately drops the
display like when it is demanding power. I haven't ESR'd any caps yet,
but don't see any visibly distressed either. I disconnected two ribbon
cables from the power board to check a few voltages. I have 5.2 volts
where it says it should be, but am missing the 12 volts on the two
seperate connectors. I was trying to trace the PCB backwards from the
connector pins to locate the source, but it was getting late. I
checked several surface mount resistors and transitiors on the bottom
of the board, but haven't located a fault yet. I will continue with
looking over the power supply, and update this post if I find the
problem. Thanks again group.

 

[Arfa Daily]

<stokesbr@cox.net> wrote in message
news:381ac3d7-e6c5-4858-ab5b-848bd114ea31@l11g2000yqb.googlegroups.com...
On Jan 31, 1:27 pm, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:

"William Sommerwerck" <grizzledgee...@comcast.net> wrote in message

news:hk3v1o$qk2$1@news.eternal-september.org...





If bad joints are hard to spot, why not just redo all
of them with tin/lead solder?

Because unless you remove better than 95% of the
lead-free solder the resulting alloy is too far from the
eutectic and vastly increases the risk of a bad joint!

Absolutely correct, quite aside from the fact that it is illegal
for a professional repairer in the EU to repair a post-June 2006
piece of equipment that's built using lead-free, with anything
other than lead-free.

I suspected that.

As a professional repairer myself, I observe this, much as I hate
doing so and, without looking into the status and location of a
poster too closely, I would not recommend that he or she does
any different.

Also, have you ever tried doing a successful blanket resolder
on a complex board that is covered in surface mount as well
as conventional components? On an average LCD power supply,
there is probably better than 1000 joints.

I assumed we were talking about only the electrolytics.

I'm glad I have a big roll of eutectic lead solder. (Don't report me!
grin&gt

Would that it was just bad joints on electrolytics we were talking about
...

Arfa- Hide quoted text -

- Show quoted text -

Thanks to all for the advice. Sorry for the late reply (been working
night shift). I have looked over the power supply (checked some of the
components) since the set does startup, but immediately drops the
display like when it is demanding power. I haven't ESR'd any caps yet,
but don't see any visibly distressed either. I disconnected two ribbon
cables from the power board to check a few voltages. I have 5.2 volts
where it says it should be, but am missing the 12 volts on the two
seperate connectors. I was trying to trace the PCB backwards from the
connector pins to locate the source, but it was getting late. I
checked several surface mount resistors and transitiors on the bottom
of the board, but haven't located a fault yet. I will continue with
looking over the power supply, and update this post if I find the
problem. Thanks again group.



Most LCD power supplies are not just one supply, but actually three. One is
the standby supply and this typically produces either 5v, 3v3, or both. I
would guess that the 5v2 that you are seeing is your standby supply. The
other two supplies are the PFC supply, and the main supply. The PFC supply
is a 'front end' one responsible for producing the raw supply to the main
section with a power-line draw that doesn't upset the electricity supply
company. The main supply usually produces +12v,
+ 24v and +34v for the tuner (though not always that one). Sometimes, there
will also be additional +5v and +3v3 rails. All of these rails are switched
on by the system control micro on the main board.

But here's where it then gets tricky ...

Most LCD power supplies are covered in protection circuits, and if a
'problem' is detected on any second level rail - that's over-current or
over-voltage - the whole TV is immediately reset by momentarily interupting
the standby supply, which removes the supply to the system control micro,
which then removes the "on" signal to the PSU ...

All of which makes it difficult to troubleshoot, unless you have spare
boards to try, and detailed schematics. One thing that is quite common is a
problem with the backlight inverter, which causes it to draw too much
current, although as you say that you can see a logo come up before a blue
screen, I'm a little loath to go down that route. Usually, if you disconnect
the plug going to the backlight inverter board, and the fault that's causing
the power supply to shut back down is on there, then the TV will come on and
stay on, and you will hear normal sound, and if you shine a strong light at
the screen at an angle, you may also be able to see a picture.

Beyond these basic checks, there is likely little more that you will be able
to do. Oddly enough, I was discussing this just last Friday with a colleague
who has a shop specialising in LCD and plas repairs, and I asked him how he
goes on with problems of sets that won't come out of standby where the cause
is on the mainboard itself, which is also common, and may well be the case
on your TV. He told me that he keeps all of the boards from insurance
write-offs with broken screens and cabinets, and then repairs, where
possible, by using them to board-swap. Beyond that, he said, it's pretty
much scrap 'em.

Arfa

 

On Feb 1, 3:50 am, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:

stoke...@cox.net> wrote in message

news:381ac3d7-e6c5-4858-ab5b-848bd114ea31@l11g2000yqb.googlegroups.com...
On Jan 31, 1:27 pm, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:





"William Sommerwerck" <grizzledgee...@comcast.net> wrote in message

news:hk3v1o$qk2$1@news.eternal-september.org...

If bad joints are hard to spot, why not just redo all
of them with tin/lead solder?

Because unless you remove better than 95% of the
lead-free solder the resulting alloy is too far from the
eutectic and vastly increases the risk of a bad joint!

Absolutely correct, quite aside from the fact that it is illegal
for a professional repairer in the EU to repair a post-June 2006
piece of equipment that's built using lead-free, with anything
other than lead-free.

I suspected that.

As a professional repairer myself, I observe this, much as I hate
doing so and, without looking into the status and location of a
poster too closely, I would not recommend that he or she does
any different.

Also, have you ever tried doing a successful blanket resolder
on a complex board that is covered in surface mount as well
as conventional components? On an average LCD power supply,
there is probably better than 1000 joints.

I assumed we were talking about only the electrolytics.

I'm glad I have a big roll of eutectic lead solder. (Don't report me!
grin&gt

Would that it was just bad joints on electrolytics we were talking about
...

Arfa- Hide quoted text -

- Show quoted text -

Thanks to all for the advice. Sorry for the late reply (been working
night shift). I have looked over the power supply (checked some of the
components) since the set does startup, but immediately drops the
display like when it is demanding power. I haven't ESR'd any caps yet,
but don't see any visibly distressed either. I disconnected two ribbon
cables from the power board to check a few voltages. I have 5.2 volts
where it says it should be, but am missing the 12 volts on the two
seperate connectors. I was trying to trace the PCB backwards from the
connector pins to locate the source, but it was getting late. I
checked several surface mount resistors and transitiors on the bottom
of the board, but haven't located a fault yet. I will continue with
looking over the power supply, and update this post if I find the
problem. Thanks again group.

Most LCD power supplies are not just one supply, but actually three. One is
the standby supply and this typically produces either 5v, 3v3, or both. I
would guess that the 5v2 that you are seeing is your standby supply. The
other two supplies are the PFC supply, and the main supply. The PFC supply
is a 'front end' one responsible for producing the raw supply to the main
section with a power-line draw that doesn't upset the electricity supply
company. The main supply usually produces +12v,
+ 24v and +34v for the tuner (though not always that one). Sometimes, there
will also be additional +5v and +3v3 rails. All of these rails are switched
on by the system control micro on the main board.

But here's where it then gets tricky ...

Most LCD power supplies are covered in protection circuits, and if a
'problem' is detected on any second level rail -  that's over-current or
over-voltage  - the whole TV is immediately reset by momentarily interupting
the standby supply, which removes the supply to the system control micro,
which then removes the "on" signal to the PSU ...

All of which makes it difficult to troubleshoot, unless you have spare
boards to try, and detailed schematics. One thing that is quite common is a
problem with the backlight inverter, which causes it to draw too much
current, although as you say that you can see a logo come up before a blue
screen, I'm a little loath to go down that route. Usually, if you disconnect
the plug going to the backlight inverter board, and the fault that's causing
the power supply to shut back down is on there, then the TV will come on and
stay on, and you will hear normal sound, and if you shine a strong light at
the screen at an angle, you may also be able to see a picture.

Beyond these basic checks, there is likely little more that you will be able
to do. Oddly enough, I was discussing this just last Friday with a colleague
who has a shop specialising in LCD and plas repairs, and I asked him how he
goes on with problems of sets that won't come out of standby where the cause
is on the mainboard itself, which is also common, and may well be the case
on your TV. He told me that he keeps all of the boards from insurance
write-offs with broken screens and cabinets, and then repairs, where
possible, by using them to board-swap. Beyond that, he said, it's pretty
much scrap 'em.

Arfa- Hide quoted text -

- Show quoted text -

I was hoping not to see that last sentence, but I do thankyou for the
info. Perhaps I should clarify.....I don't loose standby power supply
since the screen is still lightly illuminated after the logo
dissapears, and the green power light remins lit. The menu display
comes up when commanded, but intermittently gets really shaky,
sometimes goes to just black and white vetical lines, sometimes comes
back to normal, etc. When I power up the TV, I always get an onscreen
message saying "locked" after the Philips display goes away, so I'm
not sure if all this is related to one problem. Iv'e cleared the V-
chip ratings in the user menu (when the display hangs in there), but
no change. I managed to change the video source to TV (have a VCR
connected), and try to put on channel 3, but I get a message saying
channel unavailable. I pulled the power supply board and checked all
caps for ESR. I did find one faulty (102+ohms) and replaced. No
change. I also resoldered several joints that just looked really dull
and thin on solder. I would really like to figure out what the
"locked" problem is. Philips was not any help, and web searches turned
up nothing except using a four digit code to unlock, but referring to
a menu item that this TV doesn't have to use this function. Other than
accessing a service menu that I don't know how to do, is there an
electronic means of "resetting" the TV? Could all this be a software
problem? Thankyou again for advice.

 

[Arfa Daily]

<snip>

I was hoping not to see that last sentence, but I do thankyou for the
info. Perhaps I should clarify.....I don't loose standby power supply
since the screen is still lightly illuminated after the logo
dissapears, and the green power light remins lit. The menu display
comes up when commanded, but intermittently gets really shaky,
sometimes goes to just black and white vetical lines, sometimes comes
back to normal, etc. When I power up the TV, I always get an onscreen
message saying "locked" after the Philips display goes away, so I'm
not sure if all this is related to one problem. Iv'e cleared the V-
chip ratings in the user menu (when the display hangs in there), but
no change. I managed to change the video source to TV (have a VCR
connected), and try to put on channel 3, but I get a message saying
channel unavailable. I pulled the power supply board and checked all
caps for ESR. I did find one faulty (102+ohms) and replaced. No
change. I also resoldered several joints that just looked really dull
and thin on solder. I would really like to figure out what the
"locked" problem is. Philips was not any help, and web searches turned
up nothing except using a four digit code to unlock, but referring to
a menu item that this TV doesn't have to use this function. Other than
accessing a service menu that I don't know how to do, is there an
electronic means of "resetting" the TV? Could all this be a software
problem? Thankyou again for advice.


To be honest, it could be almost anything. Understood now that your power
supply is not actually going off. Have you checked the actual voltages on
the second level supplies, and run a 'scope over them, just to make sure
that none are 'hashy' ? Somehow, your fault description still seems to have
something of a power supply 'feel' about it. I'll see if any of my buddies
in the trade have had anything similar with the "locked" message on any
Philips LCDs

Arfa

 

On Feb 1, 8:14 pm, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:

snip

I was hoping not to see that last sentence, but I do thankyou for the
info. Perhaps I should clarify.....I don't loose standby power supply
since the screen is still lightly illuminated after the logo
dissapears, and the green power light remins lit. The menu display
comes up when commanded, but intermittently gets really shaky,
sometimes goes to just black and white vetical lines, sometimes comes
back to normal, etc. When I power up the TV, I always get an onscreen
message saying "locked" after the Philips display goes away, so I'm
not sure if all this is related to one problem. Iv'e cleared the V-
chip ratings in the user menu (when the display hangs in there), but
no change. I managed to change the video source to TV (have a VCR
connected), and try to put on channel 3, but I get a message saying
channel unavailable. I pulled the power supply board and checked all
caps for ESR. I did find one faulty (102+ohms) and replaced. No
change. I also resoldered several joints that just looked really dull
and thin on solder. I would really like to figure out what the
"locked" problem is. Philips was not any help, and web searches turned
up nothing except using a four digit code to unlock, but referring to
a menu item that this TV doesn't have to use this function. Other than
accessing a service menu that I don't know how to do, is there an
electronic means of "resetting" the TV? Could all this be a software
problem? Thankyou again for advice.

To be honest, it could be almost anything. Understood now that your power
supply is not actually going off. Have you checked the actual voltages on
the second level supplies, and run a 'scope over them, just to make sure
that none are 'hashy' ? Somehow, your fault description still seems to have
something of a power supply 'feel' about it. I'll see if any of my buddies
in the trade have had anything similar with the "locked" message on any
Philips LCDs

Arfa

Thanks for help help. I'll post follow up as said.