wg k7801 issues

[lenub]

I picked up a poker machine with a 13" 7801 in it.  I turns on but the screen is only 1/3 its normal size and is centered in the middle of the screen and acts lick the vertical hold is jumpping so you really can't see a clear picture. after about 2 min. it goes to a thin line across the screen. I  adjusted almost everything to no end.
 I am going to cap it but wanted to know if anyone knows if that will solve my problem or is it something else.
I pulled the chassis and check for cold joints but didn't see anything that was bad.
   And from my search a normal k7000 cap kit will work on this ? correct

  thanks

[smartbomb2084]

Are you sure that it is a K7800?  I dont think that I have ever heard of one.  I don't see it supported on the WG website.  As far as a cap kit goes you will will need a kit that services a K7800 exclusively.

How 'bout a pic or two of the deflection board?

[qrz]

could be a dirty vert height pot , loose connections on the output ic , or the chip may be failing .....
also check vert yoke connections, as the vert stage is a "closed loop"  (all basic components must work for there to be an output signal)


qrz

[Ken Layton]

25k7191 (25"k7000)
19k79xx (19"k7000 with large neck tube)
13k78xx (13'k7000)
9k77xx   (9"k7000)
19k76xx (19"k7000 with small neck tube)

All use the k7000 capkit.

[lenub]

I checked the 4 wires to the neck coil.... what and were is the loose connections on the output ic that was pointed out in earlier response
 I am a some what new at this part of the machine. I have rebuilt em pinball machines but not to much with monitors
so any help is gladly taken
  thanks

[qrz]

I checked the 4 wires to the neck coil.... what and were is the loose connections on the output ic that was pointed out in earlier response
 I am a some what new at this part of the machine. I have rebuilt em pinball machines but not to much with monitors
so any help is gladly taken
  thanks

ok..., the pins of the vertical output integrated circuit may have intermittent connections on the solder side of the pc board.  a visual inspection should verify the integrity of these connections . there may also be poor connections elsewhere in the vert . per prev post 

this is a common fault in almost every brand of crt based television , and crt game monitors are little different.

qrz

[lenub]

I'm not making any head way on this. Now all I get is a thin line horizontal across the screen?
 the chassis is a P447a  and the neck board is a P456a
are these inter changeable with the p447 and p456?
if so I may be able to replace them
   thanks

[lenub]

had a spare ic3  ic vert output and changed it out and no help same thin line
 is there a cap that would cause this?
  I posted it in someone elses thread but didn't want to highjack his thread
so I re entered it in my original thread

[Ken Layton]

So you've installed a capkit in it already? If so then you replaced the vertical output IC with the exact same number?

So capkit installed and IC changed with the correct number. Now replace Tantalum cap C51 which is not included in capkits.