single vertical line on WG 13" K4705 - FIXED. THANKS!

[nostrebor]

I've picked up a cabinet recently with a WG13k4705 monitor, with impressive screen burn, and the game is squished down to a single vertical line. The previous owner tried and supplied another (supposed good) daughter card, but the results did not change.

I have no history at monitor repair, except basic discharge/soldering/cap kit stuff, so I'm looking for some advice on this particular problem.

Any help will be much appreciated!

Thanks,

Dave.

EDIT: clarity of description.

[MonitorGuru]

Do you literally mean sprites or the entire screen is a single vertical line?

[nostrebor]

Do you literally mean sprites or the entire screen is a single vertical line?  If the picture is full but the characters are thin, then it's a gameboard problem. But if the entire picture is squished, it's a monitor problem.

Entire picture is squished into one line. Board tests perfect on my Moon Patrol monitor.

In what orientation is it? (normal 4:3 like a TV set -- e.g. horizontal game, or rotated 3:4 like classic games like Pacman?)

If normal 4:3, then your horizontal deflection is bad. If rotated 3:4, then your vertical deflection is bad.

When the monitor is setting in the normal 4:3 position, the squished line is vertical

Check that all 4 yoke wires are securely pluged into the circuit board.  With the monitor off and yoke wire unplugged from the circuit board, check the DC resistance (set your digital multimeter on 200 OHM (no Kohm) setting).  Yellow+Green should be around 10-15 (or 50-60) ohms, and Red+Blue should be around 1.5 to 3.5 ohms.

If either is 0 then the yoke wires are fried and you need a new yoke and need to do a yoke swap or tube+yoke swap.  if both read good, then the problem is located in your circuit board of the monitor (chassis).

Will test late tonight and I'll post results tomorrow...

... thanks for the help!

[Ken Layton]

If you have a single line running up and down then the width coil is broken/disconnected. Also, this chassis is well known for many bad solder joints on the foil side of the main board as well as on the "hor/ver" (a.k.a. "XY") board.

[nostrebor]

OK. So I lost my NIC (or worse?) in my computer last night Have to wedge in some time to get a part and fix that now I'm sure that my wife will motivate me to fix her internet connection first, so bear with me for a few days on further test results.

 Y+G tests to 8.2 ohms, R+B tests to 3.3 ohms. This is on the yoke, where the wires unplug. Y+G seems a bit out of range. Is this a sign of trouble?

Based on your input ken, it sounds like I need to pull the chassis, check that coil, and check/reflow some solder joints I need the practice anyway, so I'll get on that ASAP...

Thanks for the help!

[Ken Layton]

The width coil is mounted to the right of the monitor main board. It can be tested with an ohmmeter without having to remove the monitor. It has two brown wires connected to it.

This monitor has a very low impedance yoke and those readings look normal.

[nostrebor]

The width coil is mounted to the right of the monitor main board. It can be tested with an ohmmeter without having to remove the monitor. It has two brown wires connected to it.

This monitor has a very low impedance yoke and those readings look normal.

Ken,

Did a little search on the width coil, but didn't get the answer I was looking for. So... when testing the coil am I looking for simple continuity, or a certain ohm reading or range?

Also, thanks for the yoke reading verification.

Dave.

[Ken Layton]

Continuity on the width coil. Be sure both wires are connected to the coil. Sometimes vibration will cause one of the brown wires to it (coming from the main board) to break off.

[nostrebor]

Finally found some time to work on the monitor.

Width coil has continuity, wires were barely connected. Replaced/re-soldered the two wires and still have the same single vertical line.

What's next?

Thanks.

[Ken Layton]

Next step should be to install a capkit and while the main board is out inspect for bad solder joints (in particular around the connector header pins going to the plug-in boards).

[nostrebor]

OK.

Thanks Ken.

[nostrebor]

After an extended break, I'm back at this monitor.

Installed a capkit. re-flowed all the connector header pins, and cleaned up/re-flowed some other suspect solder points as needed.

Good news is that the collapsed line is gone.

Bad news is that now I have NOTHING! I replaced the fuse, even though it checked out, and still no joy. Am I missing something obvious here?

[Ken Layton]

If you got a capkit from Zanen Electronics then you replaced the trimpot on the video interface board. It will need to be readjusted in order to see a picture.

[nostrebor]

Thanks Ken,

I ran it through from one end to the other, in small increments, and still no picture. No nothing actually.

[Ken Layton]

If you have another monitor or game that has a Wells 4600 monitor in it the hor/ver and video interface boards are the same. Try a different hor/ver board.

When you did the capkit did you remember to fully push down the power supply board (which had to be removed to do the kit)?

[nostrebor]

Ken,

I actually have another H/V board, it had no effect before the capkit, and it has no effect now. So no joy there. I have no other working Wells monitor to scavenge from.

I'm not following you on the power supply board. The only two boards I removed were the H/V board and the Video Interface board. The power comes in on the corner directly into the main board. Do you mean the 6-wire plug that comes fron the H.V. Unit that supplies the anode? I'll try re-seating that one just in case.

[nostrebor]

After some hours of frustration I pulled this thing back apart and walked through it with a wiring diagram. It was dead because I plugged a set of wires into the main board that went to the neck board Should have paid more attention I guess.

After correcting this oops, I still had a vertical problem, but now it was a roll. Replaced the vert pot, and it is fixed and running!

Thanks to all who helped, especially To Ken, for his multiple replies.