Kortek K1-2-VO or SF 2001 horizontal width cap help

[jhaberthur]

I have a Kortek SF 2001 or is it a K1-2-VO as indicated on Bob Roberts monitor identification page? 

In either event, It's in beautiful condition and installed in a Ms. Pacman Cab.  The color is great, the alignment is nearly complete, I just can't seem to shrink the horizontal width down enough to get into the display area.  I'd say I've got about 10% overscan on the width and it has just killed the high score and extra lives display. 

After attempting to adjust the coil I found a cracked ferrite core.  I couldn't find the stock replacement so I went with a wells-gardner from a horizontal width cab after reading the musings of Ken and what do you know but it worked!  So I'm currently able to adjust from 120% percent overscan to 110% (guessing at these percentages).  The kicker of all this... I live in Reno, NV, a city away from KORTEK USA in Sparks, NV and they don't support this board. 

So I need to recap the board right?  Sure... that's what bobrobert's page said.. but that's a bit past my ability. 

I'd be plenty grateful if somebody could help identify which cap needs replacing, and what resistance I should change it to.  I've included some clear pictures and have limited access to the board as it's at a friends house across town. 
Thanks in advance,
James

[ed12]

jhaberthur
post to rickn
he is a nick here
do it pm he will answer u

ed

[jhaberthur]

Fair' nuff.  Thanks for the quick reply. I'll give it a go.

[jhaberthur]

Well no reply as of yet. Other ideas ?

[grantspain]

did you change the entire coil or just the core?

old korteks used to suffer from horizontal size issues due to the 50v 47uf cap near the flyback

[jhaberthur]

I repleced the entire coil.  What would I replace this50v 47uf cap with to address this issue?

[grantspain]

i do not know if that coil from a wells would be correct,not likely

that chassis looks brand new so possibility of cap failure is low

[jhaberthur]

Yes the guy I bought the cabinet from told me it was a new monitor.  I looked all over for an exact replacement but man the parts just aren't around.  Maybe itit's not the original but it does work to adjust the h width. I'm just fishing for a functional workaround

[grantspain]

the problem is if the coil has a different inductance,it will not give you the correct adjustments

in any case i think you may have a size jumper on that chassis-i can seen a header connector on it-if you do have this it should be marked N and W
this is located just above the deflection coil connector-its a red wire with a single grey connector

[jhaberthur]

Ok I'll check it out tomorrow if i can.  The only single wire jumper i see is the red wire with the grey connector (hard to see maybe I32?) that hooks up in the center of he board right next to C213. 

I'm not seeing a N or W label.  do i just unhook the jumper and check it out?  I'm a bit foggy on the advice here.

[ed12]

oh its there
n=normal
w=wide
bet it is set to n=normal giving u under width
replace the cap also
there cheap enough

ed

[jhaberthur]

Oh on the board connected to the deflection coil. Only thing I didn't grab pictures of. Ok thanks for the advice, ill give it a shot this week when I can make a trip cross town. Thanks!

[ed12]

i can see it clear as a bell
u see where the yoke hook's up ?
forward or reverse ?
that little jumper u c is the with jumper

ed

[Rickn]

Sorry for the delayed response... I do not always check the forums.
Pls understand we are not Kortek but more than happy to help! If anyone has a schematic, I will be happy to take a look.

Rickn

[jhaberthur]

Thanks for all the ideas!  I'll be trying my hand at implementing these changes tonight.

[jhaberthur]

The jumper indicated was set on the W header.  I changed it to the other one labeled S2 and that did bring the screen in a bit.  So Thanks for that tip. 
Unfortunately I feel that I have the wrong resistance on the replacement coil as it is still presenting with width overscan. 

Soooo I'm at this:

1. Should i recap and change the resistance?
2. Should I attack the coil and try to find out a workable replacement as the original is seriously nowhere to be found.
3. Should I buy a new board and say to Hades with this whole operation?

[grantspain]

hmm i do not know enough about this chassis to be sure but i hope someone else may give an opinion on this

what happens if you leave that wire link disconnected?

[ed12]

jhaberthur
no you are getting it
u might need to tweak a few things
if u are running mame  ? then try 15khz s/w
if not running it native to the machine?
we can re-time the horz frq >we go easy here<
but it can be done

ed

[jhaberthur]

If i leave the jumper connection undone then i get a narrower screen (step in the right direction! thanks team!)
If i leave the jumper connection  on W, i get a really wide screen (how it was hooked up)
If i leave the jumper connection on S2, i get the exact same as if it were undone.

[jhaberthur]

Also, to clarify:  I am not running Mame.
I am running an original Pacman board that has been converted to a Ms. Pac.

[grantspain]

right i believe the jumper is meant to be left off to give a narrow screen,it makes sense as the other header is not marked as would be expected
i think your size coil may be a little out of spec,is there no way you can refit the original coil and find a ferrite core that will fit

[jhaberthur]

You know I was thinking that...  If there was a denser core that i could fit into the one I have now.
 Additionally I could refit the original if I had a new core.  I don't believe I messed up the threads, but the core is still locked in the old coil. 
Where can i get a new ferrite core?

[grantspain]

in this situation i grab one off a scrap chassis but i guess you do not have this luxury

i would imagine this chassis is just an upgraded version of the ktn or ktm-f chassis,maybe worthwhile looking for a non worker cheap on ebay

[grantspain]

http://www.ebay.co.uk/itm/Kortek-KI-2-VO-ARCADE-MONITOR-CHASSIS-Good-Condition-Complete-but-Untested-/221251240672?pt=LH_DefaultDomain_0&hash=item33839a02e0

[jhaberthur]

Yup I'm looking at that one. Its a fair price too. Sure 40 seems steep for just a coil but I'm willing.  Unfortunately I have a sneaking suspicion that this coil still wouldn't fix it. Its a replacement monitor setup and I fear it never was dialrd in properly. 
In any event I emailed that listing owner to check on the condition of the coil on that board.
Thanks all for your help and ideas. I very much appreciate it.

[ed12]

now we are getting some where
>replacement<
here is what u need to do
dial in the horz freq to the yoke.
do u see the 2 red caps right in front of the yoke connector ?
these are your :tunning: caps :ie they set the yoke freq and timming:.
they should be high voltage type
by that i mean 600+ volts,and ploy style
them are the 1's we tweak

ed

[jhaberthur]

I checked out the ratings of the two caps in the picture that are nearest the jumper lead. The longer one at location c412 read 472 J S 1600V  NPPS 910 MEPP.  The other at lcoation c413reads 152 J S 1600V NPPS906 mepp

[jhaberthur]

I checked out the ratings of the two caps in the picture that are nearest the jumper lead. The longer one at location c412 read 472 J S 1600V  NPPS 910 MEPP.  The other at lcoation c413reads 152 J S 1600V NPPS906 mepp

[ed12]

yup thats them
1600v
they tie the horz output to the yoke
+tune it at the same time
u can adjust there value by a bit
and by a bit i mean less then a mf >micro-fraud<
let me see what u can do
give me a day with them
values

ed

[jhaberthur]

Thanks ed!

[ed12]

ya they look like .0047
and .0015
they are saftey caps
if u go to far out of range u will snap the neck of the tube off
can u read the horz winding restinace for me?
altleast it will give me a starting point.
maybe rickn will chime in now ?
as he knows tunning values backwards

ed

[jhaberthur]

Alright... how would I read the horizontal winding resistance?  And go slow on this one.

[ed12]

if u have meter ? digital ?
red and brown wires should be the horz side
green/blue should be vert
are these your yoke colors ?
to the plug ?
or do they differ ?
if u need i will refer back to your pic's u up-loaded

ed

[jhaberthur]

I've got access to a few multimeters. Ill get back into this project by midweek  next thursday.