Build Your Own Arcade Controls Forum

Main => Monitor/Video Forum => Topic started by: GIjoe on July 06, 2007, 04:09:31 am

Title: Bothced Yoke Flip on K7000
Post by: GIjoe on July 06, 2007, 04:09:31 am
A few months ago, I capped the K7000 in my Dedicated Double Dragon which I picked up at a Super Auction for $25 ( just thought I'd throw that in there )  :cheers:

Anywho, because I have terrible luck with monitors, I made sure that upon reconnecting everything that all was as it was before capping. When I powered it on, the colors were glorious...but the picture was mirrored...

Now, rather than post here immediately..which would be smart, my friends dad came (who claims use to be a tech.) over and told me all we needed to do was flip the yoke. He explained to me this meant just swapping the plug w/ the 4 colors around. I told him to make sure he knew what he was doing as the K7000 is broken up into 2 connectors w/ 2 colors each...not just one single plug. Apparently, the connector was keyed to not allow such an idiot move but he forced the plug, cracking the plastic around the Color connectors. Whats the icing on the cake? Oh yea, he powered it on!!!

I now have a thin vertical stream of light...which I'm told is a Horizontal Deflection problem...which is kind of ironic as my other K7000 has a Vertical Deflection problem.

1. Can anyone shed some light on what might have happened to my monitor,?possible solutions?
2. I plan on fixing THIS K7000 Chassis but would like a replacement chassis for a different K7000 - one thats beyond fixing. Any ideas on this one? I was thinking 8Liners but if others are available I'd like to know.

Thanks for your time,    - Joe
Title: Re: Bothced Yoke Flip on K7000
Post by: GIjoe on July 06, 2007, 02:13:12 pm
Anyone else ever messed up a yoke flip?
Title: Re: Bothced Yoke Flip on K7000
Post by: tta583 on July 06, 2007, 04:00:04 pm
Well, first off flipping the yoke either by physically spinning it or swapping the wires would do nothing for double images.  It would invert what you have/had.  If it would have worked you would have just had the same problem but upside down!!

This may help a little.
http://www.therealbobroberts.net/yoke.html

So, what exactly did he do?  I am a little lost in your description.  It probably does not help that its been a few months since I have had my head in a K7000.  I don't exactly recall what they look like.  Anyway.  The key phrase from Bob's page is this.  Keep in mind your wire colors could be different:

Red & white are the horizontal winding & can be reversed if pic is mirrored & the same for the brown & gray wires which are the vertical winding, but no other color combination can be made without serious damage being done to the monitor in a split second.

At a minimum I would put it back the way it was and work from there.  The single line sounds like a horizontal collapse.  Could have take out the HOT.  Worse case I guess the yoke could have taken a hit.
Title: Re: Bothced Yoke Flip on K7000
Post by: FrizzleFried on July 06, 2007, 04:05:08 pm
What you were SUPPOSED to do is flip the two connectors and plug them in to the same spots...meaning that 1234 would become 2143.   Sounds like he just flipped it all and made 1234 fit in to 4321.

Now,  I know that's bad.  Real bad.  As for HOW bad...I am not sure as I haven' t pulled THAT specific bone-headed move personally.   Give me time though.

Good luck and I look forward to hearing what someone who knows what in the hell they are talking about has to say!
Title: Re: Bothced Yoke Flip on K7000
Post by: grantspain on July 06, 2007, 04:11:58 pm
i would think that the minimum problem will be a fried resistor but it could be an awful lot of components.you would need to get a schem and trace everything back from the scan coil plug-a bit of a job me thinks
don't let your mate's dad near your cabs ever again :timebomb:
Title: Re: Bothced Yoke Flip on K7000
Post by: GIjoe on July 07, 2007, 03:07:20 am
heh, I don't even feel like approaching this. I have another yoke and tube that this chassis can be plugged into.

Should I give that a go? Would it help me narrow down the problems?
Title: Re: Bothced Yoke Flip on K7000
Post by: SirPeale on July 07, 2007, 03:43:39 am
If the entire yoke was flipped backwards then it's possible that the yoke itself was fried.  The horizontal circuit also doubles as the power circuit.  That's why the red wire on the yoke is so much heavier than the other three.
Title: Re: Bothced Yoke Flip on K7000
Post by: alexred on July 08, 2007, 06:44:21 pm
The Double Dragon PCB outputs an inverted video signal so thats why it was upside down.  It is true that you can correct this by changing the yoke connection, but to do that you have to break the plug in the middle and spin both sets of connections.  It is possible you may have broken the solder on the yoke connection on the chassis.  I had the same symptoms and that was the cause.  Look at the back of the chassis and re-flow the yoke connectors as well as the diode that is nearby.  Use a multimeter with continuity check to be sure.  There is a good flowchart you can follow to eliminate chassis problems. 
Title: Re: Bothced Yoke Flip on K7000
Post by: GIjoe on July 09, 2007, 11:49:52 am
Thanks Alex, I wouldn't have even thought to check Yoke Joints themselves. Gonna rip the chassis out now.

I'll keep you posted  :)
Title: Re: Bothced Yoke Flip on K7000
Post by: Popcorrin on July 09, 2007, 12:21:56 pm
Double check and make sure all of your yoke wires are plugged in.  The sympton you describe could be as simple as one of the wires not being plugged in.  I've actually done this before and had the same sympton.  I thought I had all the wires plugged in but I actually missed one of the pins.
Title: Re: Bothced Yoke Flip on K7000
Post by: GIjoe on July 12, 2007, 02:05:28 am
Double check and make sure all of your yoke wires are plugged in.  The sympton you describe could be as simple as one of the wires not being plugged in.  I've actually done this before and had the same sympton.  I thought I had all the wires plugged in but I actually missed one of the pins.

That was it! I've got picture back but I've come to another problem. I heard some static coming from the back followed by a burning smell and small puff of smoke. The game was powered on for about 10 seconds but I immediately shut it off.

K7000's are out to get me...I know it!

Any ideas? I haven't looked at the PCB since this happened. It couldn't possibly be something like dust, a loose ground or having the anode plugged in incorrectly ( I never quite feel like I've clipped both pins lol )

Thanks
Title: Re: Bothced Yoke Flip on K7000
Post by: SirPeale on July 12, 2007, 06:59:28 am
Examine your flyback for burned spots.
Title: Re: Bothced Yoke Flip on K7000
Post by: shardian on July 12, 2007, 10:22:04 am
This one is easy: make the guy give you enough money to buy a drop in replacement monitor.