Changing a flyback

Reddogg

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I've done several cap kits in the past, but am about to change out my first flyback on a K7000. Other than the standard method of discharging the monitor under the anode cap, is there anything else I should do before removing/desoldering the flyback from the board?

Also, the monitor is horizontally mounted, and right now from time to time the picture will "bounce" up and down for a few seconds at a time, every once in a while.

What causes that, and should or could a cap kit fix it?

Thanks KLOVers!

Happy Holidays!
 
flybacks are easy to do. I forget if the G2 wire's hardwired on the K7000 or not (kinda like the CRT ground wire -- most people splice that in half between the tube and neckboard and use wirenuts to reconnect it later --- DO NOT do that with the G2 wire though :)) ... every new flyback I've bought as of late did not come with the slide on connector on the G2 wire, so I wound up desoldering the terminal/pin out of the neckboard and just soldered the wire in.

focus wire goes in and out the same way... just lift open the neck socket, unhook the wire out of the holder, lift out ... reverse the steps for installing the new flyback.

outside of that, it's a desolder the old flyback, solder in the new. sometimes the base pins get a little bent, make sure your through-holes are very clean and opened as much as you can to reduce the amount of time you're putzing around with trying to install the new flyback.

your "bounce" problem could more than likely be a cold solder thing. I would reflow ALL the pots on both the neck board and deflection board (if your adjustment pots are on there), and if you have a remote board, reflow all of those. do the video signal header that your JAMMA video connector plugs into as well.

anything else that may look suspect, reflow those too. lol personally on the K7000 in my Street Fighter Alpha 3 (which has a partial crack in it along the neck socket) I reflowed EVERYTHING on it. haven't had any issues with colors or the heat circuit breaking and the tube shutting off since then.

and if you didn't cap it, do so. you'll be very satisfied with the results.
 
Replacing a K7000 flyback is fairly simple:

1) Remove the screw holding the top of the flyback to the metal bracket that goes over it (if it's still there).

2) Remove the screw holding the metal bracket to the left side wall.

3) Remove the plastic cover on the back of the neckboard socket and desolder the wire that goes to that focus pin. (some models do not have a way to unsolder this wire, so just cut it about 4 inches from the socket, and splice the new wire to it using solder and heatshrink).

4) Unplug the G2 connector from the neckboard. You'll need to cut the wire about 3 inches from the single-pin molex and splice it onto the wire from your new flyback.

5) Unsolder the 10 pins of the flyback and remove it. There are 3 black clips on the flyback that hold it in place, but wiggling it side to side should make it pop out fairly easily. Make sure you removed all of the solder, as pulling on a flyback that isn't completely free can cause small cracks to appear in the board, breaking traces and causing problems later.


Put in the new flyback in reverse order. Your new flyback will most likely not have a spot for the screw that was removed in step 1. Don't worry about it...
 
I just installed one on another monitor tonight, my third. The hardest part for me is getting the pins to line up, they never quite do and I end up spending 15 minutes with needle nose pliers bending them ever so slightly until I get it to fit in. I second the advice of solder sucking and cleaning up the holes as much as possible so they are as big and clean as they can be, it will make lining all the pins up and fitting them in easier. Other than that it's a piece of cake, quite a quick and easy repair/upgrade even for a novice.

ps- if you're doing a cap kit at the same time, while the old flyback is off, replace all the caps in that area before installing the new one, it makes replacing the caps easier
 
I just installed one on another monitor tonight, my third. The hardest part for me is getting the pins to line up, they never quite do and I end up spending 15 minutes with needle nose pliers bending them ever so slightly until I get it to fit in.

If you want to make this easier to do, line the pins of the flyback up with the holes ON THE BOTTOM of the chassis first. While they won't all fit due to the footprint being backwards, you can line up the spacing of each pin by putting one over a hole then making sure the next pin is over the next hole. Do that to all of them, then flip the chassis back over and it should slide right in...
 
To splice or not to splice G2 wire?

I'm a little confused by the above examples.

One says to splice the G2 wire:
Unplug the G2 connector from the neckboard. You'll need to cut the wire about 3 inches from the single-pin molex and splice it onto the wire from your new flyback.

and the other says not to:
flybacks are easy to do. I forget if the G2 wire's hardwired on the K7000 or not (kinda like the CRT ground wire -- most people splice that in half between the tube and neckboard and use wirenuts to reconnect it later --- DO NOT do that with the G2 wire though :)) ... every new flyback I've bought as of late did not come with the slide on connector on the G2 wire, so I wound up desoldering the terminal/pin out of the neckboard and just soldered the wire in.

Which is correct?
 
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I'm a little confused by the above examples.

One says to splice the G2 wire:


and the other says not to:


Which is correct?

If you notice, he said NOT to use wirenuts to splice it, and I said to use heatshrink and solder to splice it.

You need to splice it, but you need to do it the right way....
 
If you notice, he said NOT to use wirenuts to splice it, and I said to use heatshrink and solder to splice it.

You need to splice it, but you need to do it the right way....

Hey modessitt, I really appreciate the help, and I don't mean to be a dumb noobie (I just don't want to screw anything up), but if I read the above correctly, when you said "heatshrink and solder" you were referring to the focus wire, and not the G2.

So, it sounds like as long as they (G2 and focus wire) are both soldered back together, and covered in heatshrink, then all will be good.

Or am I still a cofunsed...bumd...doobie...:)

Thanks again.
 
Yes, that is correct. I have soldered and heatshrunk both the G2 and the anode wire.

Although you won't need to do the anode wire on a K7000, unless it has a brightener wired in that you want to remove. You MAY need to do the focus wire if you have one of those weird sockets where it can't be removed easily...
 
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Success! Flyback changed, cap kit done.

Unfortunately, the pic still bounces up and down from time to time even though I reflowed all solder on all the pots, and the video input headers on the monitor pcb.

I also have a broken green cutoff pot. When I turn it, it does change, but not with varying degree. It's like all or nothing. The knob just keeps turning and never stops. But, none of it's legs are broken.

I've never changed a pot before. How does one set it BEFORE changing it, so that when installed it changes properly as the knob is turned?

Thanks.
 
1) for your pic jumping, you may want to change your hold pots.

2) Just turn the pot all the way down for color pots, then turn it up to where you want it. If you change the hold pots, try to set them at approximately the same place the old ones are at now to keep from stressing the oscillators too much, then adjust as necessary.

If you're going to replace a couple pots, you might as well get an entire pot replacement kit...
 
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