Rattanee
New member
WG K7000... Horizontal collapse... what jolly fun....
Okay so I have this WG K7000 that I have a history with at this point. This thing has gone out of it's way to stop me from making it work since the day I got it.
When I got it, it had jailbars but worked okay... so okay, time to recap this sucker... I did a recap, replaced a few trimpots that were flakey, and a ceramic cap or two that were chipped.
I noticed that there was a plastic piece under the pcb, thought it just fell in there sometime during it's life. Turned out the chasis was arcing to the frame and it was put there to stop that from happening... Replaced a diode (D18), then after even sealing the flyback up with silicone, it was still arcing here and there, even managed to fry my test pcb with it...
I put it aside to work on when I have the time...
Recently I found a new flyback locally rather cheap, so I pulled it out to fix. Replaced the flyback, and upon powerup, amidst a horrible screech the monitor went into shutdown. No ground cable to the tube attached... thought that was the issue, so I go and attach it and try again, screechin noise, flash, nothing... Fuse blew, HOT a total short across all three legs, D18 total short (it also turned out that my replacement for this diode was inadequate for the task...).
So today I got two new HOTs in the mail, and a diode that's fast enough to replace D18 (though rated at 12 Amps... but I'm hoping that should not be a problem). It is a BY459X/1500. It has basically the same ratings as the sanyo diode that's virtually unavailable in Europe (NTE replacement costs $31 to ship a SINGLE diode to Hungary... I bought the new flyback for that price...)
I installed them, put in a new fuse holder, new fuse, fire it up, and... yaaay... I've got high voltage, monitor sounds normal aside from a faint fluctuation of frequency on powerup (I might just be imagining this... not sure... if it's there, it's very faint)...
Out of safety I still didn't give it an input. After metering the input leads and everything I was going to touch for leaking voltage (found nothing luckily) I turned up the flyback to see the raster... and all I got was a vertical line... (So yes it is a Horizontal collapse, I'm not mixing it up with a vertical problem)
The new hot is an original Sanyo part.
I've been unable to dig up anything concerning this sort of failure on this chassis, so I'm open to all ideas you guys may have...
I'm wondering at this point, if it's possible that the diode I put in actually needs a certain load to function properly... It might not conduct without a given load? Would I get the same results if I omit D18?
Since I get HV, I'm assuming this is a problem somewhere after the HOT. I checked both the linearity and the horizontal width coil, they are both soldered in properly and are conducting properly aswell. I checked the traces for continuity in this section, all test okay. Diodes D18 and D15 test okay aswell.
-I don't have an ESR meter, but I pulled C38, it reads at .406uF.
-C36 is definitely not shorted, so even if it's not good ESR-wise, it should not cause a collapse I think.
-C69... -where- is C69 supposed to be located? I looked until my eyes fell out but could not for the life of me find it, and it wasn't on the board layout drawing either that I had (even though the parts list listed it).
-What kind of resistance should I get across the linearity and width coils? Near zero right ?
Any ideas where I go from here?
(Btw the yoke connector fits snugly, yoke coil meters 11 ohms or so measured at the plug so it should not be a connection issue...)
Okay so I have this WG K7000 that I have a history with at this point. This thing has gone out of it's way to stop me from making it work since the day I got it.
When I got it, it had jailbars but worked okay... so okay, time to recap this sucker... I did a recap, replaced a few trimpots that were flakey, and a ceramic cap or two that were chipped.
I noticed that there was a plastic piece under the pcb, thought it just fell in there sometime during it's life. Turned out the chasis was arcing to the frame and it was put there to stop that from happening... Replaced a diode (D18), then after even sealing the flyback up with silicone, it was still arcing here and there, even managed to fry my test pcb with it...
I put it aside to work on when I have the time...
Recently I found a new flyback locally rather cheap, so I pulled it out to fix. Replaced the flyback, and upon powerup, amidst a horrible screech the monitor went into shutdown. No ground cable to the tube attached... thought that was the issue, so I go and attach it and try again, screechin noise, flash, nothing... Fuse blew, HOT a total short across all three legs, D18 total short (it also turned out that my replacement for this diode was inadequate for the task...).
So today I got two new HOTs in the mail, and a diode that's fast enough to replace D18 (though rated at 12 Amps... but I'm hoping that should not be a problem). It is a BY459X/1500. It has basically the same ratings as the sanyo diode that's virtually unavailable in Europe (NTE replacement costs $31 to ship a SINGLE diode to Hungary... I bought the new flyback for that price...)
I installed them, put in a new fuse holder, new fuse, fire it up, and... yaaay... I've got high voltage, monitor sounds normal aside from a faint fluctuation of frequency on powerup (I might just be imagining this... not sure... if it's there, it's very faint)...
Out of safety I still didn't give it an input. After metering the input leads and everything I was going to touch for leaking voltage (found nothing luckily) I turned up the flyback to see the raster... and all I got was a vertical line... (So yes it is a Horizontal collapse, I'm not mixing it up with a vertical problem)
The new hot is an original Sanyo part.
I've been unable to dig up anything concerning this sort of failure on this chassis, so I'm open to all ideas you guys may have...
I'm wondering at this point, if it's possible that the diode I put in actually needs a certain load to function properly... It might not conduct without a given load? Would I get the same results if I omit D18?
Since I get HV, I'm assuming this is a problem somewhere after the HOT. I checked both the linearity and the horizontal width coil, they are both soldered in properly and are conducting properly aswell. I checked the traces for continuity in this section, all test okay. Diodes D18 and D15 test okay aswell.
-I don't have an ESR meter, but I pulled C38, it reads at .406uF.
-C36 is definitely not shorted, so even if it's not good ESR-wise, it should not cause a collapse I think.
-C69... -where- is C69 supposed to be located? I looked until my eyes fell out but could not for the life of me find it, and it wasn't on the board layout drawing either that I had (even though the parts list listed it).
-What kind of resistance should I get across the linearity and width coils? Near zero right ?
Any ideas where I go from here?
(Btw the yoke connector fits snugly, yoke coil meters 11 ohms or so measured at the plug so it should not be a connection issue...)

