Problem Monitor Chassis / Board Started Crackling and Sparking

eliotcole

eliotcole

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I'll update with full details of the monitor and MB tomorrow ... but the area that was going wild was behind the shield, here:
IMG_20250531_135219.jpg IMG_20250531_135209.jpg IMG_20250531_135150.jpg IMG_20250531_135135.jpg IMG_20250531_135128.jpg​
I'm really just looking for why this might have happened.
Then I'll look to getting it sorted out.
---
If it helps, after I IMMEDIATELY disconnected it and bravely ripped out the board ... I checked the mains going into the cab and the wiring which had replaced the original wiring in the cab blew the fuse in the kitchen ... so ... that's a thing ... probably not related ... but definitely good to find out before I shoved this back up against a wall!
 
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gunblade

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yikes its a zenith, most of the time arcing is from flyback and the zenith flyback is not available
the connection of the yoke is awful, a disaster waiting to happen
only other things that cause arcing are bad solder joints, insulation sheet on HOT damaged and crt earth not connected to neck

first thing to do is show a photo of the solder side of the chassis
 
eliotcole

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It's almost like I read your mind ... as I'd looked at this and took a photo (not here just now) because it's horrid.
gunblade said:
first thing to do is show a photo of the solder side of the chassis
Click to expand...

OK, so ... basically zenith = bad. Good to know.

I'll see if I can just find a whole 'nother chassis / MB for this tube / neck / etc / whatever ... because I would love to switch it all to 240v and just escape the whole 110v ecosystem in this cab.

Alright, cheers, @gunblade ... if I manage to, I'll post a lot more info when I get the chance. Either way, thanks for this!!
 
Flyback2021

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eliotcole said:
It's almost like I read your mind ... as I'd looked at this and took a photo (not here just now) because it's horrid.


OK, so ... basically zenith = bad. Good to know.

I'll see if I can just find a whole 'nother chassis / MB for this tube / neck / etc / whatever ... because I would love to switch it all to 240v and just escape the whole 110v ecosystem in this cab.

Alright, cheers, @gunblade ... if I manage to, I'll post a lot more info when I get the chance. Either way, thanks for this!!
Click to expand...
It could just be a case of finding a compatible replacement chassis if this zenith is dead (sounds likely). I replaced one of my Zenith chassis with a wells Gardner k7000, screen size is 26”.
Running a Hantarex polo off a PSU at 240 v is the easiest monitor option imo.
Good Luck mate
 
HDemon

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eliotcole said:
I'll update with full details of the monitor and MB tomorrow ... but the area that was going wild was behind the shield, here:
I'm really just looking for why this might have happened.
Then I'll look to getting it sorted out.
---
If it helps, after I IMMEDIATELY disconnected it and bravely ripped out the board ... I checked the mains going into the cab and the wiring which had replaced the original wiring in the cab blew the fuse in the kitchen ... so ... that's a thing ... probably not related ... but definitely good to find out before I shoved this back up against a wall!
Click to expand...
Its just getting ready to open portal to other dimension :p
 
eliotcole

eliotcole

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Thanks!
... and ... well, tbf, the side says this is a WG ... Lemme find the image I've got in another thread. :)
Flyback2021 said:
It could just be a case of finding a compatible replacement chassis if this zenith is dead (sounds likely). I replaced one of my Zenith chassis with a wells Gardner k7000, screen size is 26”.
Running a Hantarex polo off a PSU at 240 v is the easiest monitor option imo.
Good Luck mate
Click to expand...
 
eliotcole

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EDIT - Oh, the crackling happened whilst I was fiddling with the size position on the chassis and the neck pots.

19", I think ... the model number on the shielding for the chassis / tube is Wells Gardner 19K7608.
gunblade said:
what size tube is it?
Click to expand...

It's the one I started on, here.

Here's a couple of the images:
Saw that number tag, there, and have zoomed in on it, here ... if it helps with identification:
WP_20250302_11_36_04_Pro.jpg​
 
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gunblade

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solder side of chassis photos are needed as any bad solder connections can be then located , arcing would be obvious with burn marks
tube label will have tube number- something like A48XYY45H,i suspect it is a 19/20" tube from the cab photos
its a zenith built wells gardner k7000a, it can be swapped with a standard k7000 - neck looks like standard from photos
 
eliotcole

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Cheers.
gunblade said:
solder side of chassis photos are needed as any bad solder connections can be then located , arcing would be obvious with burn marks
tube label will have tube number- something like A48XYY45H,i suspect it is a 19/20" tube from the cab photos
its a zenith built wells gardner k7000a, it can be swapped with a standard k7000 - neck looks like standard from photos
Click to expand...

Here's information that I've got on this PC,
WP_20250302_11_34_36_Pro.jpg WP_20250302_11_33_34_Pro.jpg​
...I'll see if I have more of the side stickers that are out of view in the first image. (y)

I'll also see if there are any 240v versions of those k7000 boards in existence. :)
 
tb2000

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Yeah as Gunblade says it's just a K7000A Zenith built chassis. At one point in the USA back in the day (in the 80's and/or 90's), apparently WG couldn't keep up with the orders for monitors that arcade cabinet manufacturers required, so they contracted Zenith to build monitors for them. For whatever reason though, Zenith felt it necessary to build their own version of the K7000 which is nearly the same as the WG built K7000 circuit wise but uses a different lopt. Unfortunately, as said above those lopts are basically non existant now (there was a batch appeared on Donberg some years ago if I remember correctly but they all got bought up very quickly - despite Donberg raising the price a few times!) At least they can be replaced no problem with a standard K7000. :)
 
eliotcole

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Looks like I lost a reply, somehow!

Anyway, yes ... thank you both. :)
gunblade said:
its 19" tube
the full range ac version of k7000 is k7201
Click to expand...
tb2000 said:
Yeah as Gunblade says it's just a K7000A Zenith built chassis. At one point in the USA back in the day (in the 80's and/or 90's), apparently WG couldn't keep up with the orders for monitors that arcade cabinet manufacturers required, so they contracted Zenith to build monitors for them. For whatever reason though, Zenith felt it necessary to build their own version of the K7000 which is nearly the same as the WG built K7000 circuit wise but uses a different lopt. Unfortunately, as said above those lopts are basically non existant now (there was a batch appeared on Donberg some years ago if I remember correctly but they all got bought up very quickly - despite Donberg raising the price a few times!) At least they can be replaced no problem with a standard K7000. :)
Click to expand...


I'll keep an eye out on this.

What are the pots on a monitor's neck board for? Could me fiddling with those have caused this to happen?
 
eliotcole

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Lovely stuff, cheers.
gunblade said:
not unless somehow you broke the neck and the sparks are coming from there, those pots are colour cut offs and gains
Click to expand...

Ah, OK. When I got it the neck board had a LOT of blutack around the connection ... Which I have completely removed. But even then, the sparks weren't flying from there ... so it's hopefully not that.

Alright, I think I might have enough to get cracking on this. Thanks, all!

I'll get some underside pics up tonight / tomoz ... and I will reflow what I can ...

---

Here's the model number as per my previous post:
WP_20250302_11_35_04_Pro-cropped.jpg
Sorry for the bad pic, it's old.​
 
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eliotcole

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