Problems Aligning the Picture on a G07

[SnotRockit]

Hello,

First of all, a huge thank you to ALL of the experts here on this forum for helping me resurrect my KLAX machine (the flyback on my chassis blew). You have been a HUGE help.

I've installed the new working G07 chassis I ordered from QuarterArcade.com. It seems to be working but I'm just having a problem trying to align the picture in the middle of the screen (see photo below).  It's sitting a little too much top left. I have found the following adjusting knobs: V-lin,  V-hold, V-height, H. Freq (not sure what H. Freq does). and have tried adjusting these (to no avail).  I also found a V. Cent and a H. Cent (I figure they are horizontal and vertical center). However, these are just three jumpers each (ie. no knobs). It seems to work when I change the jumpers for the V. Cent (but not the best)...but there doesn't seem to be any change when I change the horizonal center jumper (right, middle, left jumpers). I've tried all three and the screen still sits to the left.

Is there something else I can/need to do in order to line up the picture in the center of the screen? Do I need to do something to the choke? There are knobs on there, but they are just R, G, B...and Red, Blu, Grn. I have the user manual containing the component layout (but it's pretty "greek" to me).

I seem to be SO close...

Any/All help is appreciates. Thanks.

SnotRockit

[qrz]

h freq is the ctl for "tuning" the horizontal oscilator . 
usually , the free run  (no sync ) frequency will be around 15khz+/- a few hundred hertz.
in the 1st pic , it would appear the phasing to be a bit off .
so, try slightly adjusting the hfreq pot to eliminate the flagging .  it shouldn't take much
then adjust the h centering as needed ...


qrz

[SnotRockit]

How do I adjust the h centering? All I am able to find regarding centering is jumper/three pins labeled "H. Cent"...with the options RIGHT on one side and LEFT on the other side.

I change the jumper from the center pin to RIGHT...but it doesn't seem to "adjust the picture". Is there anywhere else on the chassis that I should look that would help me center the image?

(What exactly is the horizontal oscilator, what is its' purpose, and does it have any effect on the horizontal positioning of the image?)

Thanks for you help.

SnotRockit

[qrz]

an osillator produces a continuous waveform at a specific frequency for as long as power is applied .
 usage determines the shape the output waveform .
for digital use , the waveform will be square waves.
for analog ( radio/tv , etc) , the waveform will be a sine wave .( but again, depending on use)

in this monitor, the h osc output is a square wave . this signal is fed to a driver xistor, which increases the amplitude
thus driving a transformer .
 the secondary of the driver xformer becomes the base drive for the horiz output transistor.
the HOT , IHVT ( flyback) and reg B+ produce the 2nd anode HV, horizontal deflection, filament drive and in many sets , most of the lower voltage sources ( scan derived power supply ).

obviously, if the osc stops - everything dies in the set.

to produce a proper picture , the horiz and vert oscillators need to match the phase and frequency of the incoming signal. ( h/v sync)
the oscillators will shift frequency +/-  to match sync.  if the sync frequency is beyond the lock range of the osc , no sync will occur.  at the range edges , sync may occur , but with noticable picture flagging 

the vertical osc is very similar , except it is a sawtooth waveform .  the ramp of the waveform drives the vert output stage and then  the vert yoke .
 when the ramp falls to repeat the sequence , the crt's electron beam is brought to the screen top (vert retrace) to scan the next frame .....  LOOSELY depicted below

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qrz
               

[SnotRockit]

Wow...you really know your sh...stuff!

When I attempt to adjust he "H. Cent" (or what I think I understand from qrz's comments is the horizontal oscillator adjustment)...the screen doesn't really "move" from side to side but rather gets "fuzzy".  I have it adjusted so I get a playable picture...it's just off to the left somewhat...handicapping the player on the left. However, when I turn it on...the vertical hold is off a little (since the screen slowly moves down a little while...but then eventually stops). Is this because the vertical sync is still a LITTLE bit off?

The top of the screen image is similar to what qrz displayed... it's curvy at the top (but only there).

Are the V. Cent and H. Cent jumpers/pins supposed to move the screen accordingly? (3 pins...putting it on pin closest to side that says LEFT (should) move the picture to the left a little, middle pin = center, etc.)? I've tried chaning the pins on the H. Cent but they don't seem to have any effect on the picture's location.

I'll post some photos of the current screen image. Is this fixable?

SnotRockit