Vetical deflection issue?

[elvis]

Hi guys,

I'm a complete novice when it comes to monitors, so please if I miss something ask for the info and I'll do my best to get it.

I recently aquired a 26" Kortek unit, which the original owner says was working fine.  It had to travel a fair distance to get to me, so I'm assuming something went bust during travel.  I've not touched/tweaked anything on this unit, so I have it "as is" from the previous owner.

The monitor is currently vertically mounted.  When I turn it on, I get a single line up the middle of the unit (so it would be a horizontal line if the unit was mounted horizontally).  When I plug in a JAMMA board, I can see colour information, and hear the sound correctly.  So I'm guessing it is definitely isolated to the monitor/chassis.

One thing I notice is that "RV-202" which is the "V-POSI" trimpot is damaged.  That's all that stood out to my naked eye, but again I'm a beginner to this.

Doing a little bit of googling suggests I might have a problem with vertical deflection.  How to fix it however, is beyond me.

I looked on http://www.jomac.net.au/mon.htm and none of the units there match mine exactly.  The closest one would be http://www.jomac.net.au/images/Chassis/img88.gif . 

[EDIT] the description for that is:

Kortek
26" 110v Note: black HT Lead
Flyback ETF46L10AY

[/EDIT]

I've attached a pretty poor quality photo of mine, which I'll try to get a better image of soon (don't have access to the good digital camera at the moment).

I've got no problems with a soldering iron, so if it's a trivial replacement part, I'll happily do that.

Thanks in advance for any help/pointers.

[elvis]

More googling lead me to:

http://www.arcadehelp.com/manual/monitor/Kortek/Imperial.pdf

Although that specifically stated on another site it was for the 19" tube (does it matter which harness and which tube go together?).

Anyways... it says on page 6 that R202 (the damaged one) adjusts the height control of the picture.  Am I right in assuming that replacing R202 could fix my problems?

[hiperco]

I had a freaky problem with one of my vertical pots, where it was turned past the end and actually *shorted* itself out.  This caused total vertical collapse.  If you have an ohmmeter, measure the pot to see if its open/shorted etc.

[Ken Layton]

If the pot is damaged you could certainly lose vertical deflection. Replace it and look closely at the foil side for numerous bad solder joints too.

[elvis]

Thanks for the replies guys.

I had a friend come over today whose a little more experienced with monitors and TVs, and he confirmed the pot was broken.  He also tidied up some dirty soldering on the rear of the board for me.  He noted there was some heat marks on the unit too, so I'll look at some fan-forced air options also.

He also found the large 560uF capacitor was in very bad shape - bulging, leaking and out of its tolerances by a factor of 2.  So armed with the broken parts I'm off to an electronics shop tomorrow to find some replacements.

It looks like a cap-kit has already been used on this once before, as the smaller caps are in excellent condition.  So hopefully just these two parts replaced, all should be well for a while.

Thanks again for the input.  Hopefully it'll be a simple fix, and I can get stuck into the more important task of actually playing games.

[elvis]

Just an update:

I replaced the broken pot and input filter cap.  Still no joy.  My friend gave the board a good once over and found a hairline crack in one of the traces that connects the entire vertical signal part of the board.  With a bit of wire and solder he bypassed the break to fix it up, and now the picture is perfect.

The new 560uF/200V cap seems to have fixed any of the brightness issues the original owner was talking about.  Picture is clear, sharp and colours are bright.  I also upped the spec from 85 degrees to 105 degrees to make sure it wouldn't die any time soon.

Happy days!  Now to fix up the CP and slap a board in it.  Weee!