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A few weeks ago I found a bug in one of my TI consoles. The screen display no longer functioned correctly from normal operation.

 

image.png.4c6397253f1c3a7bdc491f5da68b84fa.png

 

I then opened the console according to the instructions from here and, as described in the article from here, unsoldered the probably defective DRAM chip.

 

I ordered some TMS4116 chips from China some time ago. I then inserted one of them into the IC socket. With the new chip, however, the screen remained black.

I then tried a few china chips, but always with a black screen. When I simply left out the chip, I got the incomplete screen again!

image.png.ca8ca4ee0a74df67a1aa4a049318618c.png       image.png.6e5c0bc40f4575b9258e65875463e66d.png This is the bad Chip from China!

 

Today I got a new delivery of NEC D416C -3 IC's, exactly these were also installed on the board. After inserting one of these ICs, the TI has a complete picture again.

 

image.png.1f7e0027b73504b596386f4e9779a2f1.pngThis is the good chip!

 


Everything seems to work as usual!

 
 

image.png.4b2515aa4410485ba1ca79fa43bd1cbb.pngimage.png.a08e55e44b880931bb895024032fc635.pngimage.png.d7fc37a4b3fe71920c44611a9a383e34.png

 

 

 

 

 

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Nice and quick job, congratulations.

 

It's an NTSC or PAL TI-99/4A?. How do you connect the TI-99/4A to the LCD monitor?

 

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7 hours ago, Papalapa said:

Nice and quick job, congratulations.

 

It's an NTSC or PAL TI-99/4A?. How do you connect the TI-99/4A to the LCD monitor?

 

Thank You,


the console is a PAL one and connected with a PHA 2036 Modulator to the RF Input of the LCD TV.

 

Today I used  a direct cable from the DIN 6pol. port of the TI to another LCD TV with YPbBr input. This was a second small project. I will post some pictures tomorrow. This way it gives me a much better picture.

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27 minutes ago, wolhess said:

Thank You,


the console is a PAL one and connected with a PHA 2036 Modulator to the RF Input of the LCD TV.

 

Today I used  a direct cable from the DIN 6pol. port of the TI to another LCD TV with YPbBr input. This was a second small project. I will post some pictures tomorrow. This way it gives me a much better picture.

I don't achieved to have a good image with my PAL TI-99/4A. I have no RF modulator but even having one I guess that the image quality will be bad.

 

I tried several TVs/monitors LCD and TRC but the colors on the screen are always wrong and most of times out of sync. Even I installed the Citrus3000 chip to convert the video ouptut to RGB unsuccesfully and actually I'm using the luminance output of the 6-pin DIN but in this case I only get a B/W signal on the monitor of course.

 

It will be great to see your pcitures tomorrow...

 

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On my main system I use a Sony Bravia KDL-19BX200 LCD TV with a PHA 2036 RF modulator.

 

This one has a very good picture, but the YPbBr cable direct to the LCD TV is better.

 

 

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This is the screen from my Sony LCD TV with a PHA 2036 RF modulator:                      And this is the screen with a direct YPbPr cable

The colors are good, but the picture is not very sharp                                                 The colors are lightly better on the LCD TV but the picture is very sharp and clean
                                                                                                                              The  more blue is only on the photo. In reality I see yellow as yellow and brown as brown.

                                                                                                                              And I can center the picture on the LCD screen

IMG_3130.thumb.JPG.4619766604bf7e699cfa769bcba3993c.JPG        IMG_3134.thumb.JPG.83dbfc4a51099a826b32279630ea9456.JPG                 

 

This is a picture with a PHA 2036 on the odys LCD TV 15-BASE
The Sony is much better!

 IMG_3133.thumb.JPG.3dc0e7aa2a3f415d87bcbd633aec0bf4.JPG       IMG_3134.JPG

 

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Gute Arbeit, Wolfgang!

Vielleicht hast Du ja auch noch Lust auf einen Elko-Tausch. ;-)

 

 

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These DRAMs seem like the most problematic thing.  Is there a way to yank all eight of them and replace them with one?

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Posted (edited)
34 minutes ago, acadiel said:

These DRAMs seem like the most problematic thing.  Is there a way to yank all eight of them and replace them with one?

No. I already exchanged some 4116 with U256D RAM from the former German Democratic Republic. There are like 4116 and work good.

 

Advice to find defective ram chips: If you want to find a defective RAM-Chip set a good 4116 in piggyback above each chip. If the error is gone you are at the defective one.

But you should test if there are more ram chips defective. Watch out that you put the test-ramchip in the right direction on the others.

Edited by Sid1968
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7 hours ago, wolhess said:

This is the screen from my Sony LCD TV with a PHA 2036 RF modulator:                      And this is the screen with a direct YPbPr cable

The colors are good, but the picture is not very sharp                                                 The colors are lightly better on the LCD TV but the picture is very sharp and clean
                                                                                                                              The  more blue is only on the photo. In reality I see yellow as yellow and brown as brown.

                                                                                                                              And I can center the picture on the LCD screen

This is a picture with a PHA 2036 on the odys LCD TV 15-BASE
The Sony is much better!

 IMG_3133.thumb.JPG.3dc0e7aa2a3f415d87bcbd633aec0bf4.JPG      

 

It is very interesting and surprising because it seems that with the Sony TV and the PHA 2036 RF modulator although the picture is not sharp at least you have the right colors on the screen. I also have a 14" 4:3 LCD Sony TV for my retrocomputers collection but I don't have the RF modulator. Even you can get the video composite signal inside the modulador in order to get better picture in the screen.

 

Until now I tried YPbPr to VGA, HDMI and RGB converters unsuccesfully with both, TRC and LCD displays and even connecting the YPbPr TI-99/4A output directly to theSony TV but colors were always incorrect. May be the solution is to find an PHA 2036 RF modulator....

 

 

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For me the best picture currently is with a PHA 2036 and the Sony LCD TV. 
 

But I will try some other configurations in the Next days.

 

I have a PHA 2037 (RGB Modulator) too and I bought a line doubler OSSC from https://videogameperfection.com/products/open-source-scan-converter/

 

So I have some possibilities.

 

The best will be a FA18A mk2, when it is available.

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On 4/18/2020 at 10:31 AM, wolhess said:

I then tried a few china chips, but always with a black screen.

 I think I got some of the same bad TMS4116 ICs from from China.  Where they from  Huayi Components by any change?  The -5V inputs were a dead short on half of mine, and none  worked.   Reordered from a US distributor at 10x the cost and all worked fine. 

 

Nice job on the repair. 

 

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please don't buy 4116 .. 4164 runs cooler, lasts longer, uses less power and..are cheap and can replace the 4116 with small modifications

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15 hours ago, arcadeshopper said:

please don't buy 4116 .. 4164 runs cooler, lasts longer, uses less power and..are cheap and can replace the 4116 with small modifications

What modifications?

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When replacing "Elkos" in this day and age, where would one find the most high-quality, high-end, longest lasting caps?  If I'm gonna do this too, I don't want to go through all the time and effort to install cheap Chinese crap that will fail in a couple of years.  I want my TI to outlive me.

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Posted (edited)
5 minutes ago, INVISIBLE said:

When replacing "Elkos" in this day and age, where would one find the most high-quality, high-end, longest lasting caps?  If I'm gonna do this too, I don't want to go through all the time and effort to install cheap Chinese crap that will fail in a couple of years.  I want my TI to outlive me.

Look in my thread. I gave productlinks.

 

 

Edited by Sid1968
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Given my recent bad experience with ChinaRam, I believe a basic TL866 programmer is worth the money, just for it's ability to check ram!

It would seem the forging bad chips has become a really industry in China.

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21 hours ago, wolhess said:

For me the best picture currently is with a PHA 2036 and the Sony LCD TV. 
 

But I will try some other configurations in the Next days.

 

I have a PHA 2037 (RGB Modulator) too and I bought a line doubler OSSC from https://videogameperfection.com/products/open-source-scan-converter/

 

So I have some possibilities.

 

The best will be a FA18A mk2, when it is available.

 

The (french) PHA2037 with Scart is good, but not as good as your screen showed here, with the Sony....

Or my 2 PHA2037er have "problems", but I don´t believe so

 

 

 

 

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Posted (edited)
1 hour ago, dhe said:

Given my recent bad experience with ChinaRam, I believe a basic TL866 programmer is worth the money, just for it's ability to check ram!

It would seem the forging bad chips has become a really industry in China.

Remembers me at the 3,5" PC NoName-Diskettes in the 1990s... where a lot of had blockerrors. I had packages where only 2 of 10 where good.

Edited by Sid1968

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Posted (edited)
47 minutes ago, Schmitzi said:

 

The (french) PHA2037 with Scart is good, but not as good as your screen showed here, with the Sony....

Or my 2 PHA2037er have "problems", but I don´t believe so

 

 

 

 

I cant believe that i have the opportunity to link my Elko-Change thread a third time in this thread.... Thx. ;-)

Since i changed the Elkos of my PHA2037 too, i show there the picture quality on my LCD-Monitor after the Elko-Change.

 

 

 

Edited by Sid1968
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2 hours ago, Schmitzi said:

 

The (french) PHA2037 with Scart is good, but not as good as your screen showed here, with the Sony....

Or my 2 PHA2037er have "problems", but I don´t believe so

 

 

 

 

Yes, I have a 2037 too and my picture is also not so good as the Sony with the PHA 2036.

 

Maybe I will test to change the Elkos!

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