The NEW Build Your Own Arcade Controls
Main => Monitor/Video Forum => Topic started by: Bender on February 16, 2008, 12:39:29 am
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(http://forum.arcadecontrols.com/index.php?action=dlattach;topic=51525.0;attach=95335;image)
Whatever I do the I can't get an Image on the left 2" or so. I have to crush the v/size to get the whole image on.
(http://forum.arcadecontrols.com/index.php?action=dlattach;topic=51525.0;attach=95337;image)
I overexposed the photo so you can see the entire monitor. I can get the image to fill all the way out to the right but it crops or wraps around on the left so much it's unplayable
(http://forum.arcadecontrols.com/index.php?action=dlattach;topic=51525.0;attach=95339;image)
And it intermittently goes crazy with the colors so I get Psychedelic Donkey Kong
so... Will a Cap kit fix these issues?
and could some one explain in noob terms what is actually happening when you replace the capacitors that fixes this?
Thanks
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Classic symptom of bad capacitors.
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a capacitor is a storage oriented device . this storage capacity is measured in FARADS. named as such for a guy named FARADAY. unitil the last 10 years , farad capacitors ( in a single package) were a dream
most electrolytic capacitors are measured in MICRO-farads ( example : 100 uF ) or .0001 Farad.
a capacitor is composed of two conductive plates seperated by an insulating medium.
the cause of ur problem is value changes in various 'lytic caps . over time and exposure to high operating temperatures , the electrolytic fluid is lost and the storage capacity drops .
a cap used in power supply fitering could be viewed as a "pour and store" device. pending the outflow rate (current), the bucket can absorb and smooth flutuations of input.
as signal coupling , a cap will block dc but, pass ac. again, changes in the insulator or plates will affect signal
passage....
an increase of "effective series resistance" accompanies the loss of electrolyte , and will restrict signal
passage/ filtering ability .
ESR is the same as putting a resistor in series with your cap. ( think RC time constants--i.e. timing circuits)
adequate explanation ?????
qrz
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qrz
[/quote]
adequate explanation ?????
qrz
Thanks for the info,
So basically over time and use the material in the capacitor breaks down or dissipates reducing the effective functionality of the capacitor?
so the monitor not being able to show an image over the entire screen is a result of a/some capacitor/s not having there full capacity?
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Electrolytic capacitors, unlike fine wine, do not get better with age. Electrolytic capacitors will go bad just sitting there whether they are being used or not. Generally, heat is the worst offender at killing capacitors. Of course hooking up a polarized electrolytic capacitor backwards will cause it to blow up!
Most arcade game video monitors have between 15 to 25 electrolytic capacitors. Usually it's not just one that's gone/going bad, it's more than one. That's why it's wise to install a "get well" or "capkit" in your monitor.
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Electrolytic capacitors, unlike fine wine, do not get better with age. Electrolytic capacitors will go bad just sitting there whether they are being used or not. Generally, heat is the worst offender at killing capacitors. Of course hooking up a polarized electrolytic capacitor backwards will cause it to blow up!
Most arcade game video monitors have between 15 to 25 electrolytic capacitors. Usually it's not just one that's gone/going bad, it's more than one. That's why it's wise to install a "get well" or "capkit" in your monitor.
thats why i usually test a new cap before installation. a few times over the years, the replacement had higher esr than the defective one :( as you know, environmental conditions of the storage area can affect shelf life ....
like wine .. good or could be vinegar ;D
qrz
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thanks everyone for the info
One more question
I got a cap kit from Mike's arcade
I replaced all of the 22 caps and 3 resistors that came in the kit. There are still a few old caps still on the board, are these not important or should I try to replace every capacitor while I have the monitor discharged and disassembled?
I know this is might be a silly question, but this is the first time I've done a cap kit and I'd like to do it right
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The ones not included are probably a few Non-polarized electrolytics (a.k.a. "bi-polar"). Yes you ought to replace those too while the chasis is out.
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Yeah!!!
cap kit done!
had a few moments of panic when I got everything back together NO video :'(
retested all the connections and everything was hooked up correctly
then I remembered before I did the cap kit when I was trying to fix the picture with all the pots and the screen went out on me when I messed with the h-sync so I moved that pot a little then turned it off and back on again and bingo! great screen! :applaud:
It's like having a brandy new monitor!!!!
there are still a couple of issues I'd like to resolve
Edit After I thought about it I realized it couldn't be the monitor because some the characters weren't affected so it must be the PCB 1. I still get a flickering of Psychedelic donkey Kong
2. the left side of the screen looks spot on but the top right quadrant the blue looks out of "register" at least that's what you'd call it in printing, I'm sure there's a different term for monitors is there any way to fine tune the adjustments?
3. there is a very slight flickering/wavy motion across the screen
any Input would be much appreciated
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#2 Did you bump/move/disturb the magnetic rings on the neck of the tube? Same for the yoke. Did one of the 3 rubber wedges fall out/come loose?
#3 Dress the video and audio wires away from AC power cord. You're picking up power line hum.
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#2 Did you bump/move/disturb the magnetic rings on the neck of the tube? Same for the yoke. Did one of the 3 rubber wedges fall out/come loose?
#3 Dress the video and audio wires away from AC power cord. You're picking up power line hum.
Ken,
I really can't thank you enough for your help!
I'll check those suggestions out later today
can you move the magnetic rings while the monitor is on/charged?
all that electricity makes me nervous, but it seems like it would be hard to adjust without the monitor being on
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after looking at it I think I may have bumped those magnetic rings
could you basically how the work?
It seems like there is a pair for each R G and B but i can't quite figure out that moving then around will do