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Author Topic: new member with old problem! monitor screwed up? or need to manual degauss?  (Read 3976 times)

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joeks

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hi everybody,
first of all, let me introduce myself. my name is barry from the netherlands and i am building a donkey kong mame cabinet from scratch with the jakobud plans (pictures on http://www.donkeykongarcade.blogspot.com). i am reading and studying pictures and threads on this board for about two months now and finding it very interesting and usefull. thank you all for sharing such an amazing amount of information about our hobby :)

but now my problem. to fit my hantarex 21" videowall monitor (mgg ev/3?) into the cabinet.  i had to cut a piece of the monitor casing. so, i used my angle grinder for that. when done, i had a nice half decased monitor. put i back in the cabinet, connected it to the computer and now the sides of the screen are curved inward! like an hourglass :( colors are fine though.
the screen worked perfectly before i started working on it's casing. it is connected through vga lead with max. res. of 800x600.

- i tried putting the monitor from the 45 degree angle (in the cabinet) back to normal, that didn't help.
- i tried putting the casing a bit back on, maybe it needed if for it's magnetic field orso, didn't help either.
- i tried all the option settings via the OSD, trapezoid etc, including degaussing, didn't work.

so i am pretty sure i must have messed it up while using the angle grinder near the tube.

anybody have an idea what to do, or can tell me more about it? please do.
i am a bit sad :) but the rest of my cabinet is coming along nicely.

thanks in advance,
barry
« Last Edit: March 31, 2008, 04:01:12 pm by joeks »

grantspain

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well an angle grinder nots the method i would have used but nevermind.
hourglass effect could be east/west correction board bad connection,pincushion adjustment out,east/west diode fault

joeks

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hi grantspain,
thanks for you fast reply.

well, i used my handsaw for as far as it would go. but it could reach the last ten centimeters in the middle of the case. hence, the angle grinder. about your answer, i did try the OSD pincushion setting. but that didn't even changed anything on screen. other settings do work, eg. width and height adjustments, stretch etc..

i don't hope it is a hardware fault, like you mention..

grantspain

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when you bring the width in does the geometry issue change in any way?

joeks

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(sorry for re-editing this, but i tried to make it more clear)

well, the hourglass stays the same.
looks like two curved black bars permanent on the screen. whatever i adjust (width, h-pos or v-pos etc.), it just seems to move alongside the black bars.
so i can't move the screen in the position where the black bars are.

but i can't make the "arc" of the hourglass larger or smaller.. arc stays the same along both sides.
« Last Edit: March 31, 2008, 04:23:04 pm by joeks »

grantspain

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what happens if you whack the side of the cab?

joeks

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i whacked it a couple of times, though not too hard. didn't do anything. maybe i have to whack it a bit harder. i'll try

grantspain

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yeah don't attack it with a sledge hammer or nowt just a swift whack will do.
in my opinion one of the east/west diodes is faulty

joeks

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whacking it hard doesn't do a thing. screen doesn't even jump a bit.

you think it might be one of the east/west diodes. so you don't think my grinder would have messed up the magnetic field?
that was my first opinion. i read somewhere that magnets (like in speakers, or drills?) could distort the image.

thanks for your help so far!

grantspain

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no its coincidence,magnets would cause discolour not geometry issues
if you had an analogue chassis i would not hesitate to say that one of the east/west correction diodes is faulty-not so sure on digital chassis ,i would need to talk to hantarex to be sure.
maybe a cable has become unplugged during the modification

joeks

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ok thanks for explaining. what do you mean by analog- or digital chassis? i will check the circuit for any loose connections

grantspain

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digital chassis have on screen adjustments which are held in a ram
analogue chassis have adjustment pots
there is something special about the yoke on these monitors if i remember correctly,trouble is i can't exactly what ???

joeks

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when i google for "yoke monitor" i came across this website: http://www.biwa.ne.jp/~shamada/fullmac/yoke_adjustmentEng.html
that gives me an idea what you mean by the "yoke", i had never heard of it.

qrz

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classic pincushion failure .
look for poor solder connections- and check the pin circuitry

qrz

grantspain

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classic pincushion failure .
look for poor solder connections- and check the pin circuitry

qrz
what i just said,or did you not bother to read ???

qrz

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  • wrangling electrons since 1978

[/quote]
what i just said,or did you not bother to read ???
[/quote]

well....,  apparently so  :-[     i'm also "old" , and its a monday t'boot !   

BTW,  problem sounds like a classic pincushion failure ....  ;D

gracias de qrz

joeks

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so it is fixable, no permanent damage you think?

thank you for the help guys. i will check it out, or have it checked out with mentioning your findings, since i am not very skilled when it comes to soldering.
« Last Edit: April 01, 2008, 01:39:08 am by joeks »

Ken Layton

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If you are NOT in the USA, you might be stuck having to solder with that 'lead-free' crap solder.

Paul Olson

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I tried the smack the side and see what happens approach to fixing the picushion problem.  :cry:

The monitor went black because the game stopped working. All the lights still come on and the monitor has power, but no "Ridge Racer" coming from the speakers. Any ideas?

Thanks,
Paul
« Last Edit: April 23, 2008, 11:53:35 pm by pcolson »

Paul Olson

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OK, it is bad enough being a dumbass. It is worse when your non geek girlfriend points out how much of a dumbass you are. The cabinet is on wheels; the power supply panel was sitting on the floor. I saw that a plug was disconnected and plugged it back in. Later, my girlfriend saw the other plug sitting there. I will probably not live this one down for a while.  :-[

By the way, the pincushion is still the same. I will have to do some more research this weekend.

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Are there controls on this monitor to correct the pincushion?

Paul Olson

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I have not found a way to adjust the pincushion yet. I tried every knob I could find, but no luck yet.

I am still not sure what monitor this is. From searching on here, it seems that it may be a k8000, which I think is medium res. It is working on my ridge racer which is supposed to be standard, so I don't know. Information seems kinda hard to find on these.

Here are the P numbers, maybe the combination will mean something to you guys who know this stuff:

Chasis - P657
Power - P715
Yoke - P583

Thanks,
Paul
« Last Edit: April 24, 2008, 11:58:02 pm by pcolson »