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Author Topic: B+ Info for Sharp Image/Kortek in Neo-Geo  (Read 1942 times)

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MonMotha

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B+ Info for Sharp Image/Kortek in Neo-Geo
« on: March 08, 2011, 04:02:21 pm »
I'm on-site right now, so if someone happens to have this info and can provide it quickly, that would be most helpful.

I have one of these: http://www.homearcade.org/BBBB/monitor78.html

It's apparently a Kortek made by/for Sharp Image.  Dunno.  Mine's branded Kortek.  I've got it mostly capped (the wrong cap kit was ordered, but I've got most things replaced).  Very dim and wobbly after the capping, but otherwise crisp, which is an improvement (though I think it's dimmer).  I'd suspect the B+ is totally off after all these years and being recapped several times.  There appears to be an adjustment pot near the big smoothing cap in the upper-right corner, but I don't know where to measure it or what to adjust to.  Anybody happen to know?
« Last Edit: March 08, 2011, 06:43:22 pm by MonMotha »

grantspain

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Re: [URGENT] B+ Info for Sharp Image/Kortek in Neo-Geo
« Reply #1 on: March 08, 2011, 05:10:33 pm »
do not know about that particular chassis but have tried the following
disconnect degauss
is there a 160v-250v cap on the neck card?
does the ntc look damaged?

MonMotha

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Re: [URGENT] B+ Info for Sharp Image/Kortek in Neo-Geo
« Reply #2 on: March 08, 2011, 06:01:45 pm »
There are no electrolytics caps on the neckboard.  Just a few ceramics.

Unplugged the degauss, still very "wavy" (no change).  It's a rolling wave effect.  Difficult to describe.  I'd say it looks kinda like what you get when there's a grounding issue, but it's having a huge effect on the side geometry rather than just the normal "moving shadow" that I see most of the time.  I didn't get to replace all the caps due to the incorrect cap kit ordered, so I'll get those replaced when the proper kit comes in.

I suspect the tube is very weak.  Takes on the order of a minute to get any picture at all.

grantspain

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Re: [URGENT] B+ Info for Sharp Image/Kortek in Neo-Geo
« Reply #3 on: March 08, 2011, 06:04:11 pm »
i had a hantarex polo 2 come in with a similar fault tot he waves,it was the ntc in the power supply section

MonMotha

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Re: B+ Info for Sharp Image/Kortek in Neo-Geo
« Reply #4 on: March 08, 2011, 06:43:09 pm »
OK, it's too late to pull it and check now, but I'll check that next time when I'm fixing the remaining caps (proper kit is on order).

MonMotha

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Re: B+ Info for Sharp Image/Kortek in Neo-Geo
« Reply #5 on: March 08, 2011, 11:02:24 pm »
OK, for some reason I read that as PTC when I was going through this, so I thought you were talking about the degauss stuff still.  Yeah, a bad NTC might cause major problems like this, so I'll definitely check that the next time I'm working on this sucker.

Bob's website seems to indicate that this thing is essentially a clone of a k7000 (in fact, I had at first misidentified it as a Zenith k7000, so that makes sense).  I'm thinking that means that k7000 adjustment criteria may be useful.