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vidarw

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Hi,
Got hold of an old Danish produced arcade cabinet today with a 4 slot NeoGeo.
All the labels indicate that its produced or at least fully serviced in Jan 1993.
Cabinet is in a Good+ state and CRT works but it's age is shown through massive amounts of dust.

One thing that is way off is the tuning of the CRT.
The horizontal image is too wide and the horizontal position has been pushed all the way to the left to compensate.
I do however have NO idea how to correctly adjust the horizontal size and as a complete beginner on CRTs I'm super afraid to ruin anything.

If you take a look at the linked control board picture, could you please tell me how to adjust the H SIZE parameter?
Is the orange coil the one to adjust? - Seems kind of fragile.

Anyone recognize the board/monitor?

Are there any good FAQs somewhere that explain the other parameters, i.e H/V-HOLD?

Any tips on cleaning is also appreciated (ie. what do do and definitely not do).

Control board:
https://drive.google.com/open?id=0B4imyyCr0mbSY1JiaTBaSk1CdktNbDlhQWhZbThfd3htXzNF

Back of CRT:
https://drive.google.com/open?id=0B4imyyCr0mbSaWdTMjNxQUdnd0twbWo5c3FnNEhnVjZuaDZB
 
H POS will move the image left and right.
H SIZE will make the image wide or narrow horizontally. You’ll probably have to tweak both of those slightly every time you change systems (if you ever take out the neo geo)

You won’t break anything by turning those, give it a shot.

H V hold are there to help you lock onto a board’s sync signal. If you ever plug in a pcb and the image rolls in a given direction, tweaking those potentiometers might help to lock it stable.
 
Apart from horizontal size everything else is a pot. You can't really do any mistakes with those.

However, horizontal size is a ferrite core. Those can be problematic nowadays as the plastic can get very brittle. Don't overturn it, and if you use a metal allen key, it will get hot fast, so don't leave it in. You can actually buy a proper trimmer tool made out of plastic for it.
 
Is it possible to adjust the horizontal image with H POS/SIZE? My CRT had a super wide image due to blown HOT. Easy fix for the repair guy...
 
Apart from horizontal size everything else is a pot. You can't really do any mistakes with those.

However, horizontal size is a ferrite core. Those can be problematic nowadays as the plastic can get very brittle. Don't overturn it, and if you use a metal allen key, it will get hot fast, so don't leave it in. You can actually buy a proper trimmer tool made out of plastic for it.
Looks like someone already broke the h-size on this one. I poked it gently with a screw driver and it looked like it was already sharded. Is it possible to get hold of replacements?

I guess i need to take the board out for cleaing and damage assesment. Was hoping i could fix this without too much handling of the connectors attached to the tube
 
Is it possible to get hold of replacements?
Unless someone knows otherwise, I'd say it would have to be salvaged from another chassis.
Someone know otherwise? ;(

The metal coil is intact, but the internal adjustment is a total mess.
Guess I'll take the board out and ask with a few of the local electronics repair shops.
Might be an old guy or two still hanging around with some proper knowledge.

Getting a similar case with a monitor here in Norway probably means doubling up on my investment,
and getting a monitor in good condition would just be pure luck.
 
Where are you in Norway @vidarw I found a Radio & TV Verksted near me that services my CRT.
I found a cap kit on eBay for my chassis so they had a complete set on hand.
If H Size is broken I would guess the horizontal output transistor could be at fault and someone has snapped the coil adjustment trying to compensate... Just a guess, but same issue I started with.
 
@nam9 Intriguing! Where is this Radio & TV verksted? Oslo maybe?
What kind of service can they provide?
 
I'm from Bergen. There are a few really old school service shops around here. Will send out some emails during the holidays.

I think I got the idea now though on how to adjust the H-size.
I found the ferrite core rod but the plastic is all broken. So I guess the plastic just has died under heat and the last person to adjust the monitor broke it and just left it hanging in silence and shame.

Can anybody explain the electrical principles of this adjustment mechanism?
Is the ferrite core amplifying or dampening the magnetic field created by the coil?
 
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