Blast City MS-2930 cyan smear/glow problem

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pulstarx
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Blast City MS-2930 cyan smear/glow problem

Post by pulstarx »

Chassis MS-2930
CRT: MS-2931-S (made 1999) / Toshiba A68LBT696X

There is a strange cyan smear or glow around some graphics. Strangely the test grid isn't that bad (beside the usual corners).

cyan glow:

http://imgur.com/EEIOepk

test grid:

http://imgur.com/lPcWHQL

Anyone has an idea?
Is this a convergence problem?

Edit: 31khz seems to worsen the effect.
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grantspain
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Re: Blast City MS-2930 cyan smear/glow problem

Post by grantspain »

has the chassis just suddenly displayed this issue?
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pulstarx
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Re: Blast City MS-2930 cyan smear/glow problem

Post by pulstarx »

Unfortunately no idea, I bought it like that.
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grantspain
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Re: Blast City MS-2930 cyan smear/glow problem

Post by grantspain »

try a different vga cable first, then consider caps
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pulstarx
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Re: Blast City MS-2930 cyan smear/glow problem

Post by pulstarx »

Cables didn't make a difference:

http://imgur.com/vTIJ1lC

I reduced the symptom by reducing R/B-gain. But it only reduces the symptom and does not solve the problem. I could see it live reducing in the NAOMI color bar test.

Now I have the problem that the picture is too dull because the gains are down. (yes DIPs are okay).
Brightness/contrast and screen on the flyback don't help.

Any idea if some specific caps are the problem?
I suspect the ones near the RGBS cable towards the neck-board.
But I can't find any schematic/manual for the ms2930...

Does the neckboard look okay?

http://imgur.com/9Hdxmv6
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grantspain
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Re: Blast City MS-2930 cyan smear/glow problem

Post by grantspain »

blue is overdriving in the colour graduation screen

all the electrolytics in the power supply section and the 10uf 250v on the neck card
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pulstarx
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Re: Blast City MS-2930 cyan smear/glow problem

Post by pulstarx »

Image

The general power supply in the top left corner?

I would have thought that the bottom right is the culprit as the RGB video signals go through there.
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Re: Blast City MS-2930 cyan smear/glow problem

Post by LegoYoda »

I literally just noticed the exact same problem on my Blasts 2930. Assuming I check out the caps and find a bad one (visually) is it worth doing all the caps at the same time? or just some to fix the issue?
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nem
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Re: Blast City MS-2930 cyan smear/glow problem

Post by nem »

It's very unlikely you will find a bloated Nichicon cap. Unless you have an ESR meter, there's no way find bad caps. And even if you have one, if you're handy with a soldering iron, it's actually quicker to just outright change them.
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