cvsoft wrote:
Just as I expected, one of the connections I made failed this morning. I'll retry it using heat in combination with pressure. If that fails, I'll solder a new wire.
Aww, sorry to hear it. I suspect that the heat source might not be sufficient; is that your thought as well? Sadly, I no longer have access to a good heat gun either. :/
I used no heat at all, that's why it didn't work. I've redone the connections with heat, and it's working so far (now at 22 hours).
cvsoft wrote:
I used no heat at all, that's why it didn't work. I've redone the connections with heat, and it's working so far (now at 22 hours).
Great, keep me in the loop, and once I get the energy to try it out on the coarse and fine connectors of some of my calculators, I too shall report back.
It failed again. I'll have to do a partial soldering of the cable. The heat allowed me to not have to do a complete cable replacement, so it's probably best for minor repairs (e.g. only problems with menu title rendering).

For repairing the fine cable on the screen side, I'd try heating a flat-end screwdriver's tip to 225-275F, and then applying enough pressure to re-melt the glue.

EDIT: It reconnected itself somehow -- It temporarily failed when its temperature fell below 63F, and reconnected when its temperature was at 73F.
That sounds frustrating indeed. :/ For the fine cable, the trick will be finding a temperature sufficiently hot to re-melt the glue without being hot enough to melt the plastic.
At room temperature, it works fine. Cool temperatures seem to cause the temporary disconnection. I'm getting the wire in about an hour from this posting.
I tried this technique on a TI-83+ today with fairly advanced ribbon cable failure, and was unable to get it to work. I used a hair dryer set to its highest heat setting, lowest airflow setting. I tried using a flat-head screwdriver to apply pressure while heating and during cool-down, I tried a small but blunt phillips screwdriver, and I tried the broad plastic end of a toothbrush. I was able to improve it somewhat, but after four heating cycles I still having nothing better than static.

Edit: I am now trying a technique involving heading a flat-head screwdriver tip using a low-temperature soldering iron, then using that to press the ribbon cable back onto the boards. I'll let you know how it goes.
Yeah; mine failed too. Partial soldering is required, but two of the wires worked!
cvsoft wrote:
Yeah; mine failed too. Partial soldering is required, but two of the wires worked!
That's about the results that I had. Two or three traces that had been showing infinite resistance (or at least >1Mohm) started functioning after the hot screwdriver trick.
Hold on, let me go back. You posted a link to the pictures of your calcs. Is the mirageOS title bar actually displayed in blue? If so, Very Happy
I'm finally getting 30-gauge wire today, and I'll let you know how the repair goes.
cvsoft wrote:
I'm finally getting 30-gauge wire today, and I'll let you know how the repair goes.
Excellent; I guess Hurricane Sandy isn't affecting you. Smile I want to try re-heating thin ribbon cable to the display of some TI-82s; any tips on that?
Just use more heat than I did.

Woohoo, I found the batteries were leaking when I went to disassemble it. Thankfully it was face-up, so no damage to the mainboard.
Well, I managed to repair the nearly-destroyed 83+ (as I announced on SAX earlier). I had to use a CircuitWriter pen to draw new traces over 4 or 5 of the existing ribbon cable traces as the conductor was no longer viable. I found that the cable needed to be insulated where it folds over itself, so a piece of paper did the trick. The CircuitWriter ink has a tendency to spread in all directions, so keeping the ink from shorting the cable was a problem. Typically I'd let it dry and scrape off the excess with a needle.



As you can see, it's not a very neat repair.
(necropost but completely relevant)
So apparently my repair for the S/N 2631068xxx 83+ failed, and it's displaying garbage again. Hopefully my CircuitWriter still works. Let's see how this one goes, now that I have working methods.
You really should just use 30AWG wire and a good soldering iron, in my opinion; I think it will produce a much more permanent fix than conductive ink. By the way, how's your fine-pitched ribbon hotfix holding up on your TI-82?
Update: beating it against a table fixed it. I'm still going to take a look inside to see if I can find the cause of the problem.

I checked on the TI-82, it is having no problems except for the temporarily missing column or two.
  
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