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Main => Monitor/Video Forum => Topic started by: moloch on December 29, 2008, 04:25:25 pm

Title: Monitor Chassis Help needed - k7000 I think
Post by: moloch on December 29, 2008, 04:25:25 pm
Monitor Chassis are where I am definitely not at my best.

I had a chassis start making that horrible electrical short smell and
the bottom has some serious scorching on it.

It has a Well Gardner Serial number of:
WG 748687

The Tube is a 25" Phillips.

I have attached a few photos.
I am building this cabinet for a friend and need to get it done as
soon as I can.

Any help here with ideas on how to repair or replace it are
appreciated.
Title: Re: Monitor Chassis Help needed - k7000 I think
Post by: moloch on December 29, 2008, 09:10:30 pm
Someone said that it looks like I blew "Big Green".

I am still pretty much in the dark and need some help.
Title: Re: Monitor Chassis Help needed - k7000 I think
Post by: SirPeale on December 29, 2008, 10:20:10 pm
That's definitely a K7000.

Holy crap!

It almost looks like a shorted yoke - the burn marks are almost in the right place.

How about another shot like the first one, but turn the board around so you can see down in the yoke connector area?
Title: Re: Monitor Chassis Help needed - k7000 I think
Post by: moloch on December 29, 2008, 11:06:05 pm
Here is a close up of the burn mark on the top of the board and one more distant shot.
Title: Re: Monitor Chassis Help needed - k7000 I think
Post by: qrz on December 30, 2008, 10:53:51 pm
fyi, it started as a a cold solder joint .  ;)

since it is in horiz deflection , it arced due to the voltage present . ( ~1300vpp pulse )

remove the carbon  ( burnt pcb ) use 18-22 ga solid wire to reconstruct the now missing copper trace .

seal with silicone rubber .

qrz
Title: Re: Monitor Chassis Help needed - k7000 I think
Post by: moloch on December 31, 2008, 12:09:40 am
Is that a special kind of capacitor, where do I go to get it or do I just order it from Bob Roberts?
Title: Re: Monitor Chassis Help needed - k7000 I think
Post by: MonMotha on December 31, 2008, 12:19:14 am
Looks like your standard high-voltage "monolithic" type.  Nothing overly special.  Might not be bad, either.

After you re-build the PCB, might also want to check that your yoke isn't shorted or damaged.  Measure resistance with a multimeter (or, even better, also inductance with an LCR if you've got one) and compare with known-correct values.

Might also want to inspect the PCB for other cold joints while its out.  They tend to come in quantity.
Title: Re: Monitor Chassis Help needed - k7000 I think
Post by: Ken Layton on December 31, 2008, 12:42:23 am
The caps in that area of the board are polypropylene high voltage.