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wow Kerm awseome!!!! alot of people at school end up renting an old, battered 83 from the library to find out that everythings screwed. pretty cool how you fixed it, well done!!!
rcplanegy wrote:
wow Kerm awseome!!!! alot of people at school end up renting an old, battered 83 from the library to find out that everythings screwed. pretty cool how you fixed it, well done!!!
Thanks, I appreciate it! If you ever find yourself with broken ones, I love to experiment with new and different kinds of broken calculators to find more things that can be fixed, so feel free to send them my way. Wink
I've never seen a black LCD before, but is this related in any way to that weird glitch where TI-83 Pluses sometimes turn on with random vertical lines? They fade quickly, btw.
Deep Thought wrote:
I've never seen a black LCD before, but is this related in any way to that weird glitch where TI-83 Pluses sometimes turn on with random vertical lines? They fade quickly, btw.
Hmm, I've never seen that one at all. Sidebar, I didn't solve the calculator I mentioned the other day, but I just got a second calculator with the black LCD symptoms, and all it took was running a ballpoint over the ribbon cable on both PCBs to get it working. Smile My line of calculators for CALCnet2.2 testing is now nine calculators long, so it's urgent that my order of three link cables arrive soon.
*bump* So the calculator I mentioned the other day turned out to only need a selective repair. I replaced the two power lines (+V and ground), as well as three of the signal lines. After two power lines and one signal line, the LCD started functioning, albeit with small glitches. The final two signal lines, which both displayed resistances in the Kohm instead of a few dozen ohms or fewer, fixed the remaining glitches. Pix of what a partial ribbon cable repair looks like below; feel free to ask questions:

*bump again* I won a TI-83+ with a slightly-cracked screen for $5.50 with shipping yesterday, and a TI-83+SE for $17.50 with shipping that has a "fuzzy screen" (doesn't look cracked, suspect just a ribbon cable issue) today. I'll post up pix and repair diagnoses as soon as the new calcs come in. Twelve-calculator CALCnet, anyone?
I am a retired EE and money is tight. I bought an 84+se for $40 without realizing that it has a missing line and a smuge on the screen. I have not found the part number for the screen and have looked everywhere for a calculator that I could part out without success. I would be willing to pay you any reasonable amount to get my 84. weregoose has written a wonderful program for me and I want to get them into the hands of children with math learning disabilities.
Hi John, great to see you again! How has everything been going? I'm glad that you're working with Weregoose on that program about which we were advising you a few months ago; you're in exceptionally capable hands with him. Regarding your TI-84+SE, the missing line is a single row or column? In the past I've been able to resolve that with just a little massaging of the ribbon cable that runs from the display controller over the top of the LCD from back to front to the top-front of the LCD. When it starts to come unstuck as the conductive adhesive wears off, rows or columns tend to start dropping out. I unfortunately have had no more success sourcing the raw LCDs that you, and while the 3mm-ish pitch on the TI-83+ LCD's ribbon cable is bad enough to solder by hand, the 84's is an even finer-pitched solder job, cramming twice as many traces into the same area, so I don't trust my ability to successfully replace a TI-84+/SE LCD.
I wonder if you can place tiny pieces of paper or cardstock, or another thin material, between each solder so they don't cross each other?
DShiznit wrote:
I wonder if you can place tiny pieces of paper or cardstock, or another thin material, between each solder so they don't cross each other?
You could try, but it would have to be reaaaaaaally thin. Cf. this image (thanks Datamath):

I tried to get a screen shot to send you but the screen shot only shows the cursor. There is a clear vertical line and then a smuge further on. Do I just junk this or is someone willing to try to recover it?
john massey wrote:
I tried to get a screen shot to send you but the screen shot only shows the cursor. There is a clear vertical line and then a smuge further on. Do I just junk this or is someone willing to try to recover it?
Did you see my suggestion about trying to massage the ribbon cable where it meets the top of the LCD? It takes a Torx-6 screwdriver and a Philip screwdriver to open the case.
While I am an EE, I am 80 years old and my hands tremble. I gave up soldering about 10 years ago. Can you make the time to do the repair? I am not in any hurry.
john massey wrote:
While I am an EE, I am 80 years old and my hands tremble. I gave up soldering about 10 years ago. Can you make the time to do the repair? I am not in any hurry.
KermMartian wrote:
Hi John, great to see you again! How has everything been going? I'm glad that you're working with Weregoose on that program about which we were advising you a few months ago; you're in exceptionally capable hands with him. Regarding your TI-84+SE, the missing line is a single row or column? In the past I've been able to resolve that with just a little massaging of the ribbon cable that runs from the display controller over the top of the LCD from back to front to the top-front of the LCD. When it starts to come unstuck as the conductive adhesive wears off, rows or columns tend to start dropping out. I unfortunately have had no more success sourcing the raw LCDs that you, and while the 3mm-ish pitch on the TI-83+ LCD's ribbon cable is bad enough to solder by hand, the 84's is an even finer-pitched solder job, cramming twice as many traces into the same area, so I don't trust my ability to successfully replace a TI-84+/SE LCD.
Most specifically:
KermMartian wrote:
Regarding your TI-84+SE, the missing line is a single row or column? In the past I've been able to resolve that with just a little massaging of the ribbon cable that runs from the display controller over the top of the LCD from back to front to the top-front of the LCD. When it starts to come unstuck as the conductive adhesive wears off, rows or columns tend to start dropping out.
DShiznit wrote:
I wonder if you can place tiny pieces of paper or cardstock, or another thin material, between each solder so they don't cross each other?


I put razorblades between pins and plenty of flux when I solder super-fine pitched ICs.
Ultimate Dev'r wrote:
DShiznit wrote:
I wonder if you can place tiny pieces of paper or cardstock, or another thin material, between each solder so they don't cross each other?


I put razorblades between pins and plenty of flux when I solder super-fine pitched ICs.
Wouldn't the rake-and-bake method be much easier at that point, assuming you're talking SMT ICs?
KermMartian wrote:
Ultimate Dev'r wrote:
DShiznit wrote:
I wonder if you can place tiny pieces of paper or cardstock, or another thin material, between each solder so they don't cross each other?


I put razorblades between pins and plenty of flux when I solder super-fine pitched ICs.
Wouldn't the rake-and-bake method be much easier at that point, assuming you're talking SMT ICs?


"rake-and bake" method?
Ultimate Dev'r wrote:
KermMartian wrote:
Ultimate Dev'r wrote:
DShiznit wrote:
I wonder if you can place tiny pieces of paper or cardstock, or another thin material, between each solder so they don't cross each other?


I put razorblades between pins and plenty of flux when I solder super-fine pitched ICs.
Wouldn't the rake-and-bake method be much easier at that point, assuming you're talking SMT ICs?


"rake-and bake" method?
Rake a soldering iron and a small amount of solder across the pads on the PCB. Put the IC roughly in place. Place it toaster oven, heat board, IC will align and joints will properly isolate as the solder melts and beads.
Ultimate Dev'r wrote:
DShiznit wrote:
I wonder if you can place tiny pieces of paper or cardstock, or another thin material, between each solder so they don't cross each other?


I put razorblades between pins and plenty of flux when I solder super-fine pitched ICs.


That's exactly what I was thinking. So there's no risk of melting or warping your razorblade?
I have a Torx T15 does not seem to fit. what size?
  
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