Need help with variant 9 screen

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bojonfield
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Need help with variant 9 screen

Post by bojonfield » Mon Jan 30, 2017 10:52 am

Hi folks!

Hoping that somebody may be able to help me setting up the variant 9 screen, I've found that there are a lot of contradictions in how to modify it and set it up for testing with the pi.

First some background, this is my second attempt at modifying this screen type (some dodgy soldering ended up in me knocking off and loosing a few smds on the first one), I began my modification as shown in the wiki (http://sudomod.com/wiki/index.php?title ... t-9_5V.jpg) removing the IC and soldering the 5V line to the appropriate pin (pin 3). This would not work and I came across another poster whos image showed the same board and the chip connected on pin 2 (http://www.sudomod.com/forum/viewtopic. ... t+9#p23963), which i then tried with no success.
photo_2017-01-30_17-34-09.jpg
photo_2017-01-30_17-34-09.jpg (158.71 KiB) Viewed 3066 times
Testing with the pi consistently yielded no results, not even a backlight so my deduction is that no power was coming through. After much trawling I found a few examples of people modifying the board by just connecting to the 5V pin without removing the chip. So I replaced the chip (I have experience with soldering surface mount components so was able to do it reasonably neatly with no bridged connections) and reattached the 5V line.
photo_2017-01-30_17-35-20.jpg
photo_2017-01-30_17-35-20.jpg (154.21 KiB) Viewed 3066 times
Now this did work, momentarily, and the picture was very fuzzy prior to loosing it, so my conclusion is that I have possibly connected it incorrectly to the pi? Initially I was connecting ground to PP6, 5V to PP1 and the white wire (signal) to the IO labeled TV. I read another post which advised against using PP1 & PP6 and used the GPIO after.
photo_2017-01-30_17-39-03.jpg
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photo_2017-01-30_17-47-26.jpg
photo_2017-01-30_17-47-26.jpg (113.97 KiB) Viewed 3066 times
This is the configuration which worked briefly. I'm at a total loss as how to continue and would really appreciate any advice! :)

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n.marek
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Re: Need help with variant 9 screen

Post by n.marek » Wed Feb 01, 2017 5:29 am

The second picture shows the red wire going to pin3, not pin2 (even though it's correct in your first picture)

edit: Also you ground wire is going to a wrong spot on the Pi, I think.

bojonfield
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Re: Need help with variant 9 screen

Post by bojonfield » Wed Feb 01, 2017 6:00 am

@n.marek thanks for the reply!

Is 5V to pin 3 not correct though? It is how the wiki suggests to mod it.

I actually have some signal now, but it is very poor, could this be because I left the IC attached or because I am attached to pin 3 rather than 2?

I couldn't locate a pinout for the chip so I can't be sure what all the pins correspond to, hence the confusion :roll:

In regards to the ground wire, I did check that that position corresponded to ground, so I think I am ok there.

As an aside I must ask if removing the chip makes a difference? I have seen plenty of mods of various boards working both with and without the chip.

Sorry for the abundance of questions by the way, I admit I could be a bit eager :lol:
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n.marek
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Re: Need help with variant 9 screen

Post by n.marek » Wed Feb 01, 2017 6:17 am

Ok, here's the chip diagram:
Image

I don't have this screen, so I can't guarantee how it should be, but I think it should be pin2.

But you're getting some picture, it could also be poorly attached ribbon cable between the board and the screen. They're sometimes pretty bad like that.

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Re: Need help with variant 9 screen

Post by n.marek » Wed Feb 01, 2017 6:24 am

And yes, the ground wire is good :)

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Re: Need help with variant 9 screen

Post by bojonfield » Wed Feb 01, 2017 7:11 am

The problem was the wrong pin, looks great now! Cheers for the help! Very much appreciated :D

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Re: Need help with variant 9 screen

Post by VeteranGamer » Wed Feb 01, 2017 1:52 pm

bojonfield wrote:The problem was the wrong pin, looks great now! Cheers for the help! Very much appreciated :D
sorry... so just to clarify....

leave the chip on

jumper cable to pin 2

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Re: Need help with variant 9 screen

Post by n.marek » Wed Feb 01, 2017 4:56 pm

I took mine off, based on some guide, but some people left them in there, so I think it makes no difference. Especially if the picture is good, as you said. :)

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Re: Need help with variant 9 screen

Post by VeteranGamer » Thu Feb 02, 2017 3:54 am

n.marek wrote:I took mine off, based on some guide, but some people left them in there, so I think it makes no difference. Especially if the picture is good, as you said. :)

so to get this right....

you have the chipped removed and jumper cable to pin 2

if so... it will be interesting to see how it performs with the chip removed and the chip still attached....

any feedback

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n.marek
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Re: Need help with variant 9 screen

Post by n.marek » Thu Feb 02, 2017 3:59 am

VeteranGamer wrote:
n.marek wrote:I took mine off, based on some guide, but some people left them in there, so I think it makes no difference. Especially if the picture is good, as you said. :)

so to get this right....

you have the chipped removed and jumper cable to pin 2

if so... it will be interesting to see how it performs with the chip removed and the chip still attached....

any feedback
Yeah, I took it off on my first build, and put the jumper to pin2, worked. Only later found out, that the chip could have stayed. Couldn't be bothered to solder it back on :)
It works :)

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