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I guess that's the advantage of TI calculators being so popular in the USA. There's only one TI-83+ Silver Edition on the UK eBay at the moment (and they tend to go for near-new prices anyway).
benryves wrote:
I guess that's the advantage of TI calculators being so popular in the USA. There's only one TI-83+ Silver Edition on the UK eBay at the moment (and they tend to go for near-new prices anyway).
I had to work hard to find a broken one; this is only the second that I've seen in about two or three months, and the first went for close to $30. Smile

@DShiznit: My (our?) pleasure; I look forward to helping you with yours when you have some to fix.
KermM, what did you use to write "Hi Cemetech" on that last calc picture? Was it your Arduindo+joystick thing? Also, congrats on fixing the calc
_player1537 wrote:
KermM, what did you use to write "Hi Cemetech" on that last calc picture? Was it your Arduindo+joystick thing? Also, congrats on fixing the calc
Cheers for the congrats. Smile My next calc to arrive will be an 83+ with a cracked screen, which might not be worth fixing; I might instead try to swap it out with a spare LCD that I have. I just use the Pen draw tool to write that, not my Arduino+joystick thing, although I could have achieved the same results with that. Smile
Out of curiosity, would it be too much trouble to have you make a video on a few of the key points of fixing the LCD and maybe posting it to youtube? You don't have to if you don't want to.
_player1537 wrote:
Out of curiosity, would it be too much trouble to have you make a video on a few of the key points of fixing the LCD and maybe posting it to youtube? You don't have to if you don't want to.
I'd be happy to do so; it would probably help a fair number of people with both EE skills and broken calculators (or the desire to fix calculators). You'll need to keep reminding me about this, though, because it will take me a while to have the free hours to do it. Smile
Epic necropost, I know, just wanted to post my thanks as I fixed an 83+ sent to me (by Jonimus) based on the contents of this thread. Very good information to know!
BrandonW wrote:
Epic necropost, I know, just wanted to post my thanks as I fixed an 83+ sent to me (by Jonimus) based on the contents of this thread. Very good information to know!
Glad to hear it! Always happy to be of help.
I bought a box of mainly junk with a TI83+ SE in it for $1 at a garage sale -- I just wanted the calc but they made me take the junk too. XD It has the lines issues and I was wondering what the proper resistance should be for the data lines and if they should be tested while in use or while batteries are taken out. I can then determine if I should replace the cable with wires completely or just selectively (when I can pull myself away from my new RPi and Freescale FRDM board). TIA!
treyjazz wrote:
I bought a box of mainly junk with a TI83+ SE in it for $1 at a garage sale -- I just wanted the calc but they made me take the junk too. XD It has the lines issues and I was wondering what the proper resistance should be for the data lines and if they should be tested while in use or while batteries are taken out. I can then determine if I should replace the cable with wires completely or just selectively (when I can pull myself away from my new RPi and Freescale FRDM board). TIA!
Welcome to Cemetech, Treyjazz; feel free to Introduce Yourself if you get a chance. What are the symptoms, exactly? Missing rows/columns or scrambled/black screen? You should test with the batteries out (you have to take off the back cover with the battery case to get to the ribbon cable anyway); all resistances should be less than 20 ohms. I'm experimenting with reliable ways to reduce the amount of soldering you need to do, but for now, solder in 30 AWG replacement wires.
It is peculiar how it is garbling the text/gfx onscreen. On a freshly cleared home screen it shows in the upper right 8x8 "tile" vertical lines in bits 2,6,7. The rest of the screen is fine until scrolling starts and then every tile gets filled with a repeated pattern of lines except for the left character column (5px) and bottom character row (8px). I did an os update to the latest version and wiped all memory. Now that i think about it it is looking like a hardware problem elsewhere that is mimicking the same problem because the screencap via TI Connect shows the same garbling. Do you think it is an LCD driver issue? I will test the resistance to rule out the screen itself.
This is precisely the symptoms of a ribbon cable problem. The reason that the Screen Capture program shows corruption is that it reads the LCD contents back from the LCD driver chip, which is on the far side of that faulty cable. So it actually corrupts data going both ways, which I always find fascinating.
Ok that is great news. Now I just have to set aside the time to test the lines and rewire the bad ones (taking into account all the time that will be utilized while swearing). Will follow up when the job is done. Thanks for the help!
treyjazz wrote:
Ok that is great news. Now I just have to set aside the time to test the lines and rewire the bad ones (taking into account all the time that will be utilized while swearing). Will follow up when the job is done. Thanks for the help!
My pleasure. Good luck, don't forget to use 30-gauge wire, and take your time with it. Smile
I had to rewire the whole thing because most of the lines in the cable were screwy. It worked like a charm the first time I rewired it. I was expecting the pitch of the contacts to be a whole lot smaller. I used 30awg for the data lines and doubled up on vcc and gnd to make sure there was enough current. I'm very happy it was a "free" fix and now my wife can use the regular 83+ I have.

On a side note: I just realized how long it has been since my TI8X programming days when i attempted to make a simple program to print a random number at a random location. I maybe just blocked it out after I went to an 89/92. Smile

Thanks again for the help!
You're very welcome; I'm glad it was such a success! I hope one or both of you perhaps has a programming Renaissance. Smile
This is my first post, ever, to any site. Discovered you when trying to find info on repair of LCD for TI-83 Plus, and very impressed with what you are doing. Have read thru all your LCD posts, opened my 83 for first time as per forum instructions, tested continuity of flex strip data and power lines to LCD PCB and all were good. Is there another flex strip from the LCD to somewhere? What is under the black tape on LCD PCB? My display is not "garbled", just missing nearly the bottom half of screen pixels except for a few full lines scattered throughout. I took a photo but don't know how to send by post. Yes, a REAL, LIVE newbie to this world. Thanks for any help you or others can give. I am ''previewing'' my post now, but it looks like it may have already posted. Not sure, so I will submit, sorry if I have double-posted somehow.[/img]
Nope, you didn't double-post. Smile Welcome to Cemetech, quaternion; we are always more than happy to help out a newbie! Especially one with such correct spelling and grammar. What you're describing, unfortunately, is indeed a failure of the ribbon cable that's under the black tape. I will be experimenting with fixing those early this week, most likely tomorrow evening, and I will be sure to share my experiences. In the meantime, would you care to Introduce Yourself?
Missing columns/rows are tough to fix, and my methods don't work for that type of connection. I'll be adding a topic and a subsection to my website on repairing calculators.

On another note, can non-83/83+/84+ calcs be affected by this? I haven't found a TI-81, TI-85, or TI-86 on eBay with the problem, despite the similar internal structure.
I have run into TI-82s and TI-86s with both types of ribbon cable failure so far. CVSoft, I will be asking you if you'd be willing to share that content for a new section that Cemetech will be introducing soon.
  
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