Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Hitachi blowing HOTS

Hitachi model #50EX10B - Yes, I posted months ago about this same set.
Sorry, but I still need help. Keeps blowing horizontal outputs. Flyback
primary checked good. Seems like it blows right when the high voltage
is starting to come up. B+ voltage dead on accurate. I have checked
several caps for leakage and ESR, just about every diode, and can't
find a faulty component. Have removed the CRT boards in case of bad
tube, but don't get high voltage. Maybe protective shutdown with no
load? Anyhow, it blows them when everything is connected. Should I be
looking on the primary side circuit of the flyback, or could this be a
faulty load on one of the secondary's circuits? I am close to bringing
it to a shop and paying for repair or info on what's wrong. Last call
on this one. Thanks group.

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darren
 
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on those TV's sometimes there is a HV ceramic capacitor that shorts
out ( right beside the H- output) however it usually has a visible
crack on it ( sometimes have to remove to see).. Hitachi TV's are
well known for flybacks to take out the H- output transistor, but can
be fairly expensive to "try it"

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JANA
 
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I have a strong feeling that the service man you bring the set to, is going
to change the flyback. These commonly cause problems in these sets.

--

JANA
_____


wrote in message
ups.com...
Hitachi model #50EX10B - Yes, I posted months ago about this same set.
Sorry, but I still need help. Keeps blowing horizontal outputs. Flyback
primary checked good. Seems like it blows right when the high voltage
is starting to come up. B+ voltage dead on accurate. I have checked
several caps for leakage and ESR, just about every diode, and can't
find a faulty component. Have removed the CRT boards in case of bad
tube, but don't get high voltage. Maybe protective shutdown with no
load? Anyhow, it blows them when everything is connected. Should I be
looking on the primary side circuit of the flyback, or could this be a
faulty load on one of the secondary's circuits? I am close to bringing
it to a shop and paying for repair or info on what's wrong. Last call
on this one. Thanks group.


  #4   Report Post  
pippy
 
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You should forget that TV. check around yardsales, moving
sales etc..... lots of times you`ll be amazed at the bargains one can
find.picked up 27`color TV panasonic with remote, and 20` inch TV with
remote for $40 bucks (both work great)at a moving sale. probly get 32` for
$75. seek and you shall find.
"darren" wrote in message
...
h- output shorting and blowing power supply transistors, and resistor
very common issue with that TV. price sounds about right.



"JANA" wrote in message
...
I have a strong feeling that the service man you bring the set to, is

going
to change the flyback. These commonly cause problems in these sets.

--

JANA
_____


wrote in message
ups.com...
Hitachi model #50EX10B - Yes, I posted months ago about this same set.
Sorry, but I still need help. Keeps blowing horizontal outputs. Flyback
primary checked good. Seems like it blows right when the high voltage
is starting to come up. B+ voltage dead on accurate. I have checked
several caps for leakage and ESR, just about every diode, and can't
find a faulty component. Have removed the CRT boards in case of bad
tube, but don't get high voltage. Maybe protective shutdown with no
load? Anyhow, it blows them when everything is connected. Should I be
looking on the primary side circuit of the flyback, or could this be a
faulty load on one of the secondary's circuits? I am close to bringing
it to a shop and paying for repair or info on what's wrong. Last call
on this one. Thanks group.




  #5   Report Post  
jango2
 
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I once blew 6 HOT's , turned out one of these blue ceramic high voltage
low value capacitors on the primary side of the fbt were open. Will
never forget that ordeal....oh boy!



  #6   Report Post  
Tom MacIntyre
 
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On Tue, 28 Jun 2005 07:35:18 -0400, "pippy"
wrote:

You should forget that TV. check around yardsales, moving
sales etc..... lots of times you`ll be amazed at the bargains one can
find.picked up 27`color TV panasonic with remote, and 20` inch TV with
remote for $40 bucks (both work great)at a moving sale. probly get 32` for
$75. seek and you shall find.


Ummm...you DO know that this is a 50" projection TV that he is
referring to, right?

Tom

"darren" wrote in message
...
h- output shorting and blowing power supply transistors, and resistor
very common issue with that TV. price sounds about right.



"JANA" wrote in message
...
I have a strong feeling that the service man you bring the set to, is

going
to change the flyback. These commonly cause problems in these sets.

--

JANA
_____


wrote in message
ups.com...
Hitachi model #50EX10B - Yes, I posted months ago about this same set.
Sorry, but I still need help. Keeps blowing horizontal outputs. Flyback
primary checked good. Seems like it blows right when the high voltage
is starting to come up. B+ voltage dead on accurate. I have checked
several caps for leakage and ESR, just about every diode, and can't
find a faulty component. Have removed the CRT boards in case of bad
tube, but don't get high voltage. Maybe protective shutdown with no
load? Anyhow, it blows them when everything is connected. Should I be
looking on the primary side circuit of the flyback, or could this be a
faulty load on one of the secondary's circuits? I am close to bringing
it to a shop and paying for repair or info on what's wrong. Last call
on this one. Thanks group.




  #7   Report Post  
Art
 
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Default

Also, probable one of the crts may be flashing over? Seen this a couple of
times flacking the h-out.
"Tom MacIntyre" wrote in message
...
On Tue, 28 Jun 2005 07:35:18 -0400, "pippy"
wrote:

You should forget that TV. check around yardsales, moving
sales etc..... lots of times you`ll be amazed at the bargains one can
find.picked up 27`color TV panasonic with remote, and 20` inch TV with
remote for $40 bucks (both work great)at a moving sale. probly get 32` for
$75. seek and you shall find.


Ummm...you DO know that this is a 50" projection TV that he is
referring to, right?

Tom

"darren" wrote in message
...
h- output shorting and blowing power supply transistors, and resistor
very common issue with that TV. price sounds about right.



"JANA" wrote in message
...
I have a strong feeling that the service man you bring the set to, is

going
to change the flyback. These commonly cause problems in these sets.

--

JANA
_____


wrote in message
ups.com...
Hitachi model #50EX10B - Yes, I posted months ago about this same set.
Sorry, but I still need help. Keeps blowing horizontal outputs. Flyback
primary checked good. Seems like it blows right when the high voltage
is starting to come up. B+ voltage dead on accurate. I have checked
several caps for leakage and ESR, just about every diode, and can't
find a faulty component. Have removed the CRT boards in case of bad
tube, but don't get high voltage. Maybe protective shutdown with no
load? Anyhow, it blows them when everything is connected. Should I be
looking on the primary side circuit of the flyback, or could this be a
faulty load on one of the secondary's circuits? I am close to bringing
it to a shop and paying for repair or info on what's wrong. Last call
on this one. Thanks group.






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