Please help!! Old TV as arcade monitor Horizontal skew

[Deepblue]

Hope someone can help locating this problem. I bought an arcade machine, but someone has mounted an old TV instead of an arcade monitor.

The top several horizontal lines are skewed. I'm able to adjust some of it, using the Horizontal Freq. pot, but it never goes away 

Hope someone is able to identify this chassis. It's marked 190-882007-01, but I'm unable to find any logo, company name or model name
I read somewhere that th 190-xxx numbers are used by ONWA. can someone confirm this??

Does anyone have any idea where to look for this failure?? I think it might be a capacitor somewhere, but where?? none of the components are burnt and all capacitors look fine 

(sorry for the bad quality pictures)

[AnotherTech]

I would guess it's a bad cap as well.  Unfortunately, without a cap tester, your best bet is to just shotgun it, replace all the electrolytic caps.  I've seen a similar problem on Tatung monitors caused by a mylar cap.  That was very hard to find, the first time.

Good luck.

[cowboygames]

Maybe I'm thinking wrong on this, but wouldn't the problem be in the vertical circuit as the picture tube(being a standard tv tube)was made origionally to be mounted longways(?)so the guns in the neck of the tube are actually sideways now? I'm assuming game CRTs were made with the neck and guns mounted for the application of use

[Deepblue]

I would guess it's a bad cap as well.  Unfortunately, without a cap tester, your best bet is to just shotgun it, replace all the electrolytic caps.  I've seen a similar problem on Tatung monitors caused by a mylar cap.  That was very hard to find, the first time.

Good luck.

Actually I have a capacitor tester, but it is a tedious job to unsolder all the caps and test them...... But I guess I'll have to get started....

[Deepblue]

Maybe I'm thinking wrong on this, but wouldn't the problem be in the vertical circuit as the picture tube(being a standard tv tube)was made origionally to be mounted longways(?)so the guns in the neck of the tube are actually sideways now? I'm assuming game CRTs were made with the neck and guns mounted for the application of use

I'm not shure what you mean.... the tube is mounted vertically, but nothing has changed (i.e deflection coil is not rotated or anything???) arcade monitors are mounted the same way????

[poppo]

Maybe I'm thinking wrong on this, but wouldn't the problem be in the vertical circuit as the picture tube(being a standard tv tube)was made origionally to be mounted longways(?)so the guns in the neck of the tube are actually sideways now? I'm assuming game CRTs were made with the neck and guns mounted for the application of use

I'm not shure what you mean.... the tube is mounted vertically, but nothing has changed (i.e deflection coil is not rotated or anything???) arcade monitors are mounted the same way????

I see what cowboygames is saying. Since that is a standard TV but is sitting 'sideways' horizontal contols becomes vertical.

[AnotherTech]

Actually I have a capacitor tester, but it is a tedious job to unsolder all the caps and test them...... But I guess I'll have to get started....

Yes, a regular cap tester can be a pain.  An ESR tester is nice, because you can test in circuit, but they're a couple hundred bucks.

The problem is in the horizontal circuit.  You can see that the right side of the monitor is messed up, up and down.  That is probably the "top" of the monitor from the circuit boards point of view.  Since the monitor has been rotated the problem appears vertically, but it's still in the horizontal circuit.

[Deepblue]

Actually I have a capacitor tester, but it is a tedious job to unsolder all the caps and test them...... But I guess I'll have to get started....

Yes, a regular cap tester can be a pain.  An ESR tester is nice, because you can test in circuit, but they're a couple hundred bucks.

The problem is in the horizontal circuit.  You can see that the right side of the monitor is messed up, up and down.  That is probably the "top" of the monitor from the circuit boards point of view.  Since the monitor has been rotated the problem appears vertically, but it's still in the horizontal circuit.

Exactly.... The screen is  mounted vertically and the problem is in the top of the screen.... I don't see why horizontal and vertical would be interchanged. the only thing that's been changed is the physical orientation of the tube!!!

[cowboygames]

If that tube was mounted horizontally, the way it was built to beimg a standard tv tube, that would be a vertical problem. Same as when a vertical out put fails on a tv and you get a thin white line ACROSS the middle of the tube

[poppo]

If that tube was mounted horizontally, the way it was built to beimg a standard tv tube, that would be a vertical problem. Same as when a vertical out put fails on a tv and you get a thin white line ACROSS the middle of the tube

Visual aid. 

[cowboygames]

Thanks Poppo, that;s what I meant and that's a vertical problem. Seems like someone else had the same problem posted on here just a few weeks ago

[AnotherTech]

Maybe I'm missing something here, but in the original pic posted by Deepblue, there appears to me to be a problem vertically along the right side of the screen.  I know that it is horizontal from the circuit boards point of view, because every monitor I have ever seen is wider than it is tall and they turn them sideways to get the taller appearance.  All the arcade games and slot machines I have ever seen are this way.  If you turn up the power on the FBT you will get retrace lines that run vertically.  They still run horizontally from the circuit boards point of view, though and anything that is skewed vertically is still in the horizontal circuit on the board.

If you look at the picture poppo posted, the image appears skewed horizontally at the the top left and at the top right.  It appears to be "wiped" to the left.  You can't tell in the middle, because there is no image displayed.  Now I am assuming that the picture tube orientation is correct in this picture, because Deepblue says "The top several horizontal lines are skewed".  I'm also assuming he understood the correct orientation of the screen and knew that is was a horizontal issue, because that's what he stated in his post and because just looking at the picture, I came to the same conclusion.

Now, unless you can tell without a schematic, which components are in which circuit, it doesn't really matter.  He just has to find the bad components and replace them.

[cowboygames]

If someone had a picture of the back of a normal game CRT it would make this a lot easier. Does the HV lead plug in at the top or on the side of those tubes? Or better yet, if he adjusts the vertical size control on the board, does the picture get taller, like it should? Or does it get wider? Which would indicate reverse operation due to the use of a standard tv CRT

[AnotherTech]

The anode (HV connection) is on the side.
Adjusting vertical size will make it wider or narrower.
Adjusting horizontal size will make it taller or shorter.

It is just a monitor turned on it's side.  The circuit board doesn't know that the monitor has been turned, except for the video going through it having to be written to show text sideways.

Edited to add that all of this is in reference to the monitor pictured in the first post and other "taller than wide" monitors.  They are just normal monitors turned 90 degrees.

[cowboygames]

Vertical size adjustments make the picture taller, that's why you get a white line straight across the middle of the tube when the vertical output fails. Horiz adjustments make it wider and provide the drive. That's why you get NO picture when the horiz output fails.

[AnotherTech]

Vertical size adjustments make the picture taller, that's why you get a white line straight across the middle of the tube when the vertical output fails. Horiz adjustments make it wider and provide the drive. That's why you get NO picture when the horiz output fails.

I understand that.  But you asked what happens "if he adjusts the vertical size control on the board, does the picture get taller, like it should? Or does it get wider?"  My post above was in answer to that.  It gets wider.

Just understand that it is an absolutely normal monitor.  It has been turned on it's side and nothing has been rewired. What was in the horizontal circuit, is still in the horizontal circuit.  But now that horizontal display APPEARS vertical.

I don't have any pictures of CRTs turned sideways, but here are 2 video slots with rotated LCDs.  One is rotated to the left, the other to the right.  If you look at the text displayed as the games boot up, it appears sideways, because the screens have been turned on their sides.  These are wide screen LCDs turned sideways to make them appear tall.

[cowboygames]

You're right, the way the tube is oriented a vertical size adjustment would make the picture wider/narrower. On a horizontally oriented(normal position)tube, it would get taller/shorter. That's my point though, taking into consideration the abnormal tube orientation, his issue would appear to be a vertical circuit problem

[channelmaniac]

BITD... for arcade games... there were issues with non-standard vertical sync rates. Each arcade game was slightly different and the worst offenders were Midway boards such as Mortal Kombat. Wells Gardner had several different revisions/patches they would do to monitors that weren't on the schematics but were to fix those tearing issues. Each involved modifications around the vertical sizing control section of the monitor.

I know it doesn't help you with this... but at least you are on the right track with checking the vertical section.

Follow the yoke leads backwards into the chassis and replace the caps in that area as a first step. While there, resolder any cracked solder joints too.

RJ

[cowboygames]

  It's hard to describe a vertical problem in a horiz context when you're looking at it in a vert context  Not that what I just said isn't confusing in and of itself, but that's a TV guy thing

[Deepblue]

Thanks guys for all your inputs, but it would be great if someone could help out with the actual problem 

In my originally posted picture, the suction cup is on the right side seen from the front i.e it would be on top on Poppo's rotated picture !!

[cowboygames]

In my opinion you have a vertical problem and as channelmaniac stated above you should start by locating the vert plug on the yoke of the CRT. Horiz and vert are usually designated with an h or v next to the plug on the yoke. Check the connections there and trace the wires back to the circuit board to identify the vert circuit on the board. From there check all major componants with board location numbers in the same series. For example, 3001 3002 3003, etc. If the plugs aren't identified at the yoke, the one of the two using smaller gauge wire will be the vertical plug. Check caps, diodes and resistors all the way back to the HVT and check solder connections within the circuit also. Exersize the vert size control knob also just to make sure the size adjusts smoothly and there's no oxidation keepingg it from working properly. Anyway, this is a good way to start in your search