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Main => Monitor/Video Forum => Topic started by: Kman-Sweden on March 29, 2010, 05:47:14 am

Title: What resistor on yoke?
Post by: Kman-Sweden on March 29, 2010, 05:47:14 am
A call out for information about a SEMCO yoke (DSE-1992 NL) on a Samsung tube.
Like Mr Ken fixed here... http://home.comcast.net/~mtpacifico/_kenskorner/files/Kortek_KT-1420A_repair_guide.pdf (http://home.comcast.net/~mtpacifico/_kenskorner/files/Kortek_KT-1420A_repair_guide.pdf)
I fixed up a old monitor with some help from you fantastic people. The tube is in great condition.

The connections on the yoke was like this..

Yellow   ----<=R=>------ Green
    |                                |
    -------------------------
    |                                |
    -------------------------
    |                                |
blue                                 red


And between green and yellow there was a unknown resistor...
I don't have a clue what size it was or even why it was there in the first place.
I had my picture mirrored and had a moment where I was brain dead and fliped the wrong wires... It lit up the inside of my cab real nice.
I have a multimeter that I can barely use if I need to measure anything.

Hope someone can help me out.
Title: Re: What resistor on yoke?
Post by: lilshawn on March 29, 2010, 03:37:45 pm
the resistor is there to up the coil resistance for use with a different chassis. some chassis don't like low ohm ratings on the vertical coil, the resistor (probably only about 1 ohm) boosts the load that the chassis board has to work with.

now that it's fried, you might as well go ahead and trash it. You've most likely cooked the chassis and/or the yoke.
Title: Re: What resistor on yoke?
Post by: sarge on March 29, 2010, 07:31:15 pm
The way the OP is describing, the way this resistor was installed it would actually lower the total resistance of the coil.  Either way it was probably installed to try and make it work with a different chassis.
Title: Re: What resistor on yoke?
Post by: Kman-Sweden on March 30, 2010, 12:55:21 am
Well I have replaced the chassi on it once already without any major problems...
I actually fried a resistor on the chassi as well but I have pictures of it from before so I can replace that one, no problems.
The yolk looks fine, well except the resistor... ;)

So do you think I could just replace the resistor on the chassi card and just skip the resistor on the yoke completely?
Could I measure something like the ohms of the yoke and compare that to something on the chassi card to see if it might work?
Title: Re: What resistor on yoke?
Post by: lilshawn on March 30, 2010, 08:32:08 am
It is possible that the damage has been kept to the items described, It's possible to fix it.
I'm just worried the the horizontal output transistor and the vertical drive chip (allong with the associated components) are dead

I'm guessing its worth a shot replacing the resistors, just be prepared for more damage
Title: Re: What resistor on yoke?
Post by: Kman-Sweden on March 30, 2010, 09:34:20 am
Hi.
Before reading your post I went along and replaced the resistor on the chassi card and just removed the blown one from the yoke.
The monitor is up and running again. ;D
There's some pulling of the picture and some stripes as well.. Top right corner seems okay..
Normal cap issue, right? See pics.

(http://www.koskimaki.se/res/MAME/crt/IMG_0171.JPG)

(http://www.koskimaki.se/res/MAME/crt/IMG_0172.JPG)

(http://www.koskimaki.se/res/MAME/crt/IMG_0173.JPG)

(http://www.koskimaki.se/res/MAME/crt/IMG_0174.JPG)
Title: Re: What resistor on yoke?
Post by: lilshawn on March 30, 2010, 09:30:43 pm
glad to see it running.

a cap kit should fix the lines. although it may just need adjustment. try to see if changing the vertical height makes a difference.