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Main => Monitor/Video Forum => Topic started by: ac3 on April 02, 2008, 12:48:40 pm

Title: WG k7401 problems.
Post by: ac3 on April 02, 2008, 12:48:40 pm
Hi all,
I recently recapped a WG K7401 in my Sports Shooting cabinet as I was having some problems with it not staying on and the imaging shaking a little bit. I replaced all but 3 or 4 caps that I couldn't find replacements for, it's been working fine for about a week today I turn it on and after about 2 minutes I hear two pops I look and the monitor is off and smoke is coming out of the back.

I can't see it could be any of the caps I just installed as they would of gone when I first turned it on?. Is it likely to be one of the few I couldn't find replacements for?. Has anyone had this happen before?. I've heard of caps being installed around the wrong way popping when powered on but never after working fine for a week. Also does anyone know where I can find a cap list for this monitor I had to go by the old caps and maybe I put a BP one where a normal one should for or vice versa?.

TIA ac3.
Title: Re: WG k7401 problems.
Post by: grantspain on April 02, 2008, 01:27:54 pm
i accidently put the wrong value cap in a hantarex once,it popped after 2 weeks.
sounds like you have the wrong value cap in somewhere
Title: Re: WG k7401 problems.
Post by: Arm123 on April 02, 2008, 02:58:51 pm
Depending on how old the monitor is and when it was last serviced.  It could be component strain from age ?  From the current flow now being corrected ?

What you think spain ?
Title: Re: WG k7401 problems.
Post by: grantspain on April 02, 2008, 03:19:06 pm

What you think spain ?

of what?
Title: Re: WG k7401 problems.
Post by: ac3 on April 02, 2008, 03:33:21 pm
It's quite a new monitor, less than five years old. Problem is if Grantspain is right I don't know what value it is as the manual lists everything except the caps.  ???  :cry:
Title: Re: WG k7401 problems.
Post by: grantspain on April 02, 2008, 03:46:20 pm
don't cry  :laugh:
http://www.wellsgardner.com/pdf/Schematics/K7400_25_inch.pdf
all your caps are stated here-although good eye sight required

http://www.wellsgardner.com/pdf/Repair/K7400_25_inch.pdf
this will help if it don't turn out to be a dodgy cap

Title: Re: WG k7401 problems.
Post by: qrz on April 02, 2008, 11:26:13 pm
and pay attention to polarity when replacing 'lytics .....

reversing will "let the smoke out" .

remember: all electronic devices are smoke powered   ;D

qrz
Title: Re: WG k7401 problems.
Post by: ac3 on April 03, 2008, 12:10:55 pm
The cap that blew was a 100uf 200v, which was installed originally.  ??? I think the new one just must of been a dud, I'll install a new fuse and keep my fingers crossed when powering it on.
Title: Re: WG k7401 problems.
Post by: ac3 on April 05, 2008, 08:00:58 am
Replaced the blown cap and fuse and now it trips the circuit.  :cry:
Title: Re: WG k7401 problems.
Post by: grantspain on April 06, 2008, 05:27:24 am
you need to check that you have not dripped some solder across tracks.
for the trip to go it would imply that you have a dead short on the primary power supply of the monitor
Title: Re: WG k7401 problems.
Post by: ac3 on April 06, 2008, 09:00:31 am
I know there aren't any solder shorts as it was working fine for a week, I've done quite a few cap kits and I'm very careful. I'm guessing whatever blew made the cap that was fine blow too and is now shorted?. Could it be the lopt?. I don't really know where to go from here unless I see something on the board that is physically damaged.
Title: Re: WG k7401 problems.
Post by: grantspain on April 06, 2008, 09:09:47 am
can't see it being the lopti
http://www.wellsgardner.com/pdf/Repair/K7400_25_inch.pdf
likely to be q101 or d104
did you replace the same value fuse?
Title: Re: WG k7401 problems.
Post by: ac3 on May 29, 2008, 05:28:26 am
I've had a chance to look at this now and it seems the second time I powered it on a lot of the components went pop. C118 was a film capacitor the schems just list it as 1.0 63v, I am guessing this means 1uf 63v?. Also R101 is bad which I cannot find on the schems does anyone know what this is?. It's got what looks like MSP 103 written on it.

TIA ac3.