nec fs59v80 fault

P

Pussynuts

Guest
Hi All,
I have a NEC FS59V80 CTV with the following fault.On switch on the
focus will arc to earth through the spark gap on the crt board and will blow
the horizontal output transistor.Replaced HOT,Flyback and associated caps
without success.Any suggestions on what could be causing it.
Cheers
Joe
 
Sounds like a faulty tube ???

"Pussynuts" <pussynuts@bigpond.com> wrote in message
news:W0KWb.53274$Wa.32134@news-server.bigpond.net.au...
Hi All,
I have a NEC FS59V80 CTV with the following fault.On switch on
the
focus will arc to earth through the spark gap on the crt board and will
blow
the horizontal output transistor.Replaced HOT,Flyback and associated caps
without success.Any suggestions on what could be causing it.
Cheers
Joe
Click to expand...
 
Yep, thats what i thought too but it seems to test ok on the crt
rejeuvenator.Checked for shorts etc.Could it be an o/c

cheers
joe
"Allan" <allanaws@hotmail.com> wrote in message
news:402be520$0$1723$5a62ac22@freenews.iinet.net.au...
Sounds like a faulty tube ???

"Pussynuts" <pussynuts@bigpond.com> wrote in message
news:W0KWb.53274$Wa.32134@news-server.bigpond.net.au...
Hi All,
I have a NEC FS59V80 CTV with the following fault.On switch on
the
focus will arc to earth through the spark gap on the crt board and will
blow
the horizontal output transistor.Replaced HOT,Flyback and associated
caps
without success.Any suggestions on what could be causing it.
Cheers
Joe
Click to expand...
 
if it does it with the neck board off the tube, it's an electroincs problem.
If not, tube problem.

Is the arcing purely because the spark gap is now carbonised or just fouled
with filth and thus not as good as a gap as originally intended?

Tried unsoldering the focus wire and hooking just your EHT probe to it (To
provide a high-resistance path to ground). This may tell you if the focus
voltage is the *source* or *destination* of the flashover.


"John" <wmp1@bigpond.com> wrote in message
news:vSTWb.53678$Wa.43734@news-server.bigpond.net.au...
Yep, thats what i thought too but it seems to test ok on the crt
rejeuvenator.Checked for shorts etc.Could it be an o/c

cheers
joe
"Allan" <allanaws@hotmail.com> wrote in message
news:402be520$0$1723$5a62ac22@freenews.iinet.net.au...
Sounds like a faulty tube ???

"Pussynuts" <pussynuts@bigpond.com> wrote in message
news:W0KWb.53274$Wa.32134@news-server.bigpond.net.au...
Hi All,
I have a NEC FS59V80 CTV with the following fault.On switch
on
the
focus will arc to earth through the spark gap on the crt board and
will
blow
the horizontal output transistor.Replaced HOT,Flyback and associated
caps
without success.Any suggestions on what could be causing it.
Cheers
Joe
Click to expand...
 
On Thu, 12 Feb 2004 12:08:22 GMT, "Pussynuts" <pussynuts@bigpond.com>
put finger to keyboard and composed:

Hi All,
I have a NEC FS59V80 CTV with the following fault.On switch on the
focus will arc to earth through the spark gap on the crt board and will blow
the horizontal output transistor.Replaced HOT,Flyback and associated caps
without success.Any suggestions on what could be causing it.
Cheers
Joe
Click to expand...
Was the tuning cap one of your "associated caps"? An OC tuning cap
would result in a very high voltage across the HOT, which in turn
would cause the EHT to rise to excessive levels.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.
 
Thanks guys,seems the tube is at fault.tried it with the neck board off and
no arcing.
Weird fault.I have not seen this before.
Cheers
Joe
"Craig Hart" <chart@nospam.ta> wrote in message
news:402ceb67@usenet.per.paradox.net.au...
if it does it with the neck board off the tube, it's an electroincs
problem.
If not, tube problem.

Is the arcing purely because the spark gap is now carbonised or just
fouled
with filth and thus not as good as a gap as originally intended?

Tried unsoldering the focus wire and hooking just your EHT probe to it (To
provide a high-resistance path to ground). This may tell you if the focus
voltage is the *source* or *destination* of the flashover.


"John" <wmp1@bigpond.com> wrote in message
news:vSTWb.53678$Wa.43734@news-server.bigpond.net.au...
Yep, thats what i thought too but it seems to test ok on the crt
rejeuvenator.Checked for shorts etc.Could it be an o/c

cheers
joe
"Allan" <allanaws@hotmail.com> wrote in message
news:402be520$0$1723$5a62ac22@freenews.iinet.net.au...
Sounds like a faulty tube ???

"Pussynuts" <pussynuts@bigpond.com> wrote in message
news:W0KWb.53274$Wa.32134@news-server.bigpond.net.au...
Hi All,
I have a NEC FS59V80 CTV with the following fault.On switch
on
the
focus will arc to earth through the spark gap on the crt board and
will
blow
the horizontal output transistor.Replaced HOT,Flyback and associated
caps
without success.Any suggestions on what could be causing it.
Cheers
Joe
Click to expand...
 
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