Tech: Wrong hoz osc. freq - WG4600
Alex Yeckley
Well, this one has been giving me fits. For
some reason the hoz oscillator is running at
18.7kHz instead of 15.7kHz, and as a result
it won't sync up. I've checked all of the
components (except resistors) in that neck
of the woods, and everything is in limits.
Anyone know which resistor & cap (or inductor?)
determines the free-running frequency?
Alex
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Alex Yeckley
Umm, that would be a WG K4600, in case anyone
was confused.
WACKO172
pitched squeal. And the picture was triple-imaged. I resorted to just fixing
another horz/vert board. If anyone knows of this fix, please let me know. Until
I have more time on my hands...I'll be able to fix it myself.
Mitchell Rohde
daughter boards... it's on the schematic. Adjust this and it will
fix the problem (horiz osc adjustment)
mitch
Alex Yeckley
Well, if you mean the hoz hold adjustment, it doesn't
operate in the right range (more like 18-20kHz instead
of 14-16kHz). The only other adjustment I could find
was the volume control on the MV board - that can't be
what you were talking about.
I should mention that I have two other interface boards
which work fine when installed in this monitor.
Any other ideas?
Alex
Alex Yeckley
> Mitchell Rohde wrote:
> There is an osc adjustment on either the motherboard or one of the two
> daughter boards... it's on the schematic. Adjust this and it will
> fix the problem (horiz osc adjustment)
Then I wrote:
> Well, if you mean the hoz hold adjustment, it doesn't
> operate in the right range (more like 18-20kHz instead
> of 14-16kHz). The only other adjustment I could find
> was the volume control on the MV board - that can't be
> what you were talking about.
Turns out that L351 must've been the adjustment he
was talking about. It does in fact coarsely adjust
the hoz osc frequency. In my case, it took three
turns of it to get it in the right range. Doh!
James Sweet
Bob Roberts
>
> Hi guys,
>
> Well, this one has been giving me fits. For
> some reason the hoz oscillator is running at
> 18.7kHz instead of 15.7kHz, and as a result
> it won't sync up. I've checked all of the
> components (except resistors) in that neck
> of the woods, and everything is in limits.
>
> Anyone know which resistor & cap (or inductor?)
> determines the free-running frequency?
>
> Alex
I send this one at least 5 times a week & haven't posted it in about
6 months, so I guess it's time again. Here's a paste....
WG-K4600 Picture slanted or off H frequency ??
Symptom:
The screen has horizontal bans of color like a barber pole or
maybe almost straightened up, but not quite, so that the picture
is slanted. Some pcbs may work fine, while others don't. Treble
pics, but stable on screen. Just not enough H range period.
Cure:
The horizontal frequency has drifted off from center. Locate the
horizontal hold control on the vertical pc card on the right hand
side of the chassis. It is the white knob on the bottom under
the long protruding black knob (V. hold). Set it to it's mechanical
center & leave it.
In the center of this same vertically mounted pc card, you will
see a shiny metal square can about 1 inch down from the top.
Looking into it you will see a red screwdriver slot. You'll need
a 12" plastic screwdriver to feed thought the hole on the metal
chassis frame, that lines up with this screw slot in the can &
adjust it until the picture straightens up. If you go the wrong way
and the picture goes out altogether, don't worry, just go back in
the opposite direction for a few turns & turn the monitor off for
a minute & then back on. This resets your auto-shutdown circuit.
Now you can continue going in the right direction until the picture
is upright.
This should solve your problem & if you use your cabinet as a
multi-game cab, you should try several of your pcbs in the game
& adjust the small white horizontal knob to a position where
any of the pcbs will plug n play.
Happy Gaming..........
--
Big Bear <bob...@bellsouth.net> Thanks The Real Bob Roberts™
For parts http://personal.msy.bellsouth.net/~bob147