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#331
Re: The VB Glitchy Display Problem
Posted on: 2018/4/7 18:11
Virtual Freak
Joined 2017/7/10
USA
98 Posts
Long Time User (1 Year)
Quote:

ZeldaFan042 wrote:
Quote:

Seam wrote:
anyone here in the usa still do the cable repairs? i dont own any tools to even attempt it


http://www.planetvb.com/modules/newbb ... php?topic_id=6885&forum=1


thank you, i hadnt stumbled across this thread yet
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#332
Re: The VB Glitchy Display Problem
Posted on: 2/16 5:14
Virtual Freak
Joined 2014/8/31
USA
83 Posts
Long Time User (4 Years) App Coder
I just want some clarification... it is normal when this problem occurs for one display to have weaker color output than the other display* in addition to horizontal lines? Or would this possibly be two different problems with my VB at once?

I noticed the horizontal lines years ago, but I decided to power up my VB as a test today and I noticed asymmetric color drive in addition to horizontal lines. My left display seems fine, but the right display seems to be in trouble :(. Might as well repair both. In any case, I want to try to repair myself, can anyone recommend a screwdriver for the deep screws?

* Noticable at the warning screen, for instance, which should have the same color intensity on both displays.
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#333
Re: The VB Glitchy Display Problem
Posted on: 2/17 4:39
Virtual Freak
Joined 1/27
78 Posts
I think when you're talking about that color drive, it's kind of where the color just totally does like this pulled out bleed effect through some/much of the space, and this on top of those straight lines right?

That is a classic sign of the cruddy glue going south on the ribbon cable connecting to the board it should have been soldered to in the first place.

I got one within the last months worth of time, and one of the eyes originally was out (left) the first day, and right worked, the next day left would pop on but right was behaving like what you wrote there. I got a solder job done by a friend and it's bright, poppy, and evenly lit for red on both sides like factory fresh.
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#334
Re: The VB Glitchy Display Problem
Posted on: 2/17 5:46
Virtual Freak
Joined 2014/8/31
USA
83 Posts
Long Time User (4 Years) App Coder
IIRC, Virtual Boy can display up to 4 shades of red at the same time from a palette of 256 shades (0 black, 255 full red). I think the VB hardware initializes the 4 shades to 255, 192, 128, and 0 (someone feel free to correct me), but you can change that if you wish. The higher the number, the more intense/bright the red is- the intensity of the red is what I mean by color drive.

Currently on my VB's right display, what should be the shade of red corresponding to 255 (max brightness), looks more like, say, 192. And 192 looks more like 128, etc. But none of the colors are actually missing on the right display, so I'm guessing the VIP is reading the relevant palette entries just fine.

This would also be a symptom of the glue losing its effect?
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#335
Re: The VB Glitchy Display Problem
Posted on: 2/17 6:20
Virtual Freak
Joined 1/27
78 Posts
I want to say yes to this only because of the way the unit I have now looked before then after the solder fix.
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#336
Re: The VB Glitchy Display Problem
Posted on: 2/17 12:15
Newbie
Joined 2018/9/5
France
5 Posts
Hey :D

Not really sure what's going on, maybe there's a contact issue with one or multiple CLK* lines ? They're basically PWM signals generated from the values you gave, and they're right in the center of the ribbon cable: http://furrtek.free.fr/?a=vbtvout

Never experimented by disconnecting them so I can't tell if what you're getting is clearly a sign of contact failure.

They're shared with both display though, so if the other display has correct shades then you can be sure the signals are generated ok.
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