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Shift838

99/4A Video Issue

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So I purchased a 99/4A that was supposed to be like new and only used once.  cosmetically it looks great, you can tell it's never had a PEB plugged in.

 

However, I am having some video issues.  

 

If you look at the Title screen you can see distortions around the color bars and quite a bit of character ghosting.

 

on the second photo upper right corner you can see quite a few vertical lines.  I see this all over the monitor when changing to darker screen colors.

 

In TI Basic you can see the ghosting well too.

 

Would this be the 9918 VDP or could this be DRAM related?

 

 

 

 

colorbars.jpg

IMG-1908.jpg

IMG-1912.jpg

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MainByte has a couple of articles on alterations of the video circuit to address output quality issues.

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This is to the composite input on your monitor/TV?  My NIB 99/4A that I got 2 years ago looks like that also - maybe not quite to that extent.  But I can see vertical lines going down the screen and some color fringing as well, depending on the colors.  Black background with white letters is very rainbowy.  It’s always been this way.

 

 

913511DF-B42D-4F2F-B46E-0DEF0DFE9AB3.jpeg

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21 hours ago, Shift838 said:

So I purchased a 99/4A that was supposed to be like new and only used once.  cosmetically it looks great, you can tell it's never had a PEB plugged in.

 

However, I am having some video issues.  

 

hehe. I've had this happen a lot. When I see a cosmetically new-looking TI-99 I figure it might have video issues (usually it's only the beige ones). I found there was a reason it was never or only lightly used, since some of these units probably were like that from the factory.

Edited by Toucan

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My console is connected via my big screen as it has a composite input. But every now and then the tv goes black with a no signal message, then pops back on. I thought maybe it's the cable so I tried another cable and I still get the same thing just once in awhile.

I'm thinking it's just the tv. 

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1 hour ago, Toucan said:

I found there was a reason it was never or only lightly used, since some of these units probably were like that from the factory.

I have the same theory regarding as-new transistor radios, often still with the box and papers. A gift from Aunt Edna? But it didn't work, so rather than make her feel bad, and not worth it to them to have it fixed and no way to return it to the store, but they can't just toss it either, so it gets stuffed in the back of a drawer.

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27 minutes ago, Ed in SoDak said:

I have the same theory regarding as-new transistor radios, often still with the box and papers. A gift from Aunt Edna? But it didn't work, so rather than make her feel bad, and not worth it to them to have it fixed and no way to return it to the store, but they can't just toss it either, so it gets stuffed in the back of a drawer.

This thread brings memories of the infamous "Russian TI-99/4A console". That was an interesting one to say the least.

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17 hours ago, GDMike said:

I never heard of that

In terms of the Russian console. I was in talks with someone who was in turn in talks with a former TI employee. The former TI employee said he had a console in Russian. I was intrigued to say the least, considering the TI came out during the Cold War/Iron Curtain days. Anyway, since the TI contact said the computer was in Russian, I was envisioning a box in Russian, screen in Russian, etc. So I ended up paying for it and had it shipped to me. When I got the TI, the box was just the regular box. So I plugged it in to see if the computer was really displaying Russian text. When the computer came on, it displayed one of these screens found on this page:

 

https://www.ninerpedia.org/wiki/Troubleshooting?fbclid=IwAR3KzYrHfdDjjrciXy7Gk_QfGJxuNaZCIcS0B7RJeXyJgi6Ba7SPZYeP6co

 

Care to guess which screen is the "Russian Screen"? :) 

 

So all that for the scrambled TI unit.

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1 hour ago, OLD CS1 said:

@Toucan Not funny, but funny. :)

When I first saw screen 11111110 on that page, I was like, hey, that's the Russian screen! :) Maybe I could edit it to give it that name, hehe. Actually, if you look at it, the TI logo could even be a sickle/hammer :)

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7 minutes ago, arcadeshopper said:

What was the mark up on the Russian machine?

Sent from my LM-V600 using Tapatalk
 

Forget what he was asking, but I seem to remember paying $50 for it. This is from a 2002 e-mail when this all went down. So not a bad price luckily. He described it as follows:

 

TI 99 4/A Equipment

8     9" monitors:  1 working & 7 non-working (use for parts)   (sold??)
1     13" monitor    (sold ??)
2     expansion modules, 1 with floppy drive
10  TI 99 4/A systems: 2 new still in the box (1 in Russian) 8 used
( 2 in box sold)
1    TI Program tape recorder
420  Blank 5 1/4" floppys (use on expansion modules)
        missalanious user guides and plugs and cables
 

Edited by Toucan
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I have a question about this.  I know that on some computers programmers used these video issues in inventive ways to enhance games.  Was this done much on the TI?  If so some games might look much different if the TMS-RGB mod or an F18A is used.  
 

thoughts?

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20 minutes ago, Keneg said:

I have a question about this.  I know that on some computers programmers used these video issues in inventive ways to enhance games.  Was this done much on the TI?  If so some games might look much different if the TMS-RGB mod or an F18A is used.  
 

thoughts?

Parsec maybe? With the multi-colored twinkling star background?

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On 9/3/2020 at 10:03 PM, Shift838 said:

anyone have a spare TMS9918 they want to part with?

Meee too meet too...ok only if you got a spare after shift838.

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1 hour ago, Toucan said:

Parsec maybe? With the multi-colored twinkling star background?

The Parsec stars use actual colors. :) The vertical stripes on the ground show substantial aliasing, but the consensus was that wasn't done on purpose.

 

Nothing on the TI I'm aware of uses the fringing on purpose.

 

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Thanks, I plan on trying the resister and capacitor fixes when I have time.  I have an AV2VGA to try to get a bigger picture by using a 4:3 VGA monitor I have, but it makes the issues worse.  I am hoping the fixes will get me at least back to what I get on my tiny composite monitor now.  I’m on the fence about things that require modifying the computer.  Things like the TIPI and FinalGROM99 really mostly duplicate functionality that you could have from vintage hardware, but much cheaper and more reliable.

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6 hours ago, GDMike said:

Ok, you actually got me on that. I let my guard down, I'm the dunce of mayberry.

I should be sorry too...
I watched @Toucan walk you ...right into it!

:grin:

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