I found an 83+ at a garage sale. Given that I can't pass up a bargain (25 cents) I bought it.
I would not turn on. Or said another way there is not indication that it is working.
Put new AAA batteries in it.
Did not install new button batteries until I get some feeling for what is ahead.
Could the button batteries be part of the problem?

Tom

Tom, nice find; I'm jealous of that price! The button battery is almost definitely not the problem. Do you have a Silverlink cable (USB on one end, 2.5mm stereo plug on the other end, translucent oblong silver box in between), or another calculator? If so, you can try to connect to the calculator to determine if it's the screen that's not working, or the entire calculator. I suspect that it's a screen issue, in which case you'd need to consider replacing/repairing the LCD ribbon cable. Have you already tried the easy step of turning the contrast up?

When I got my 86 from a garage sale, I thought it was broken too, but it was just the contrast was set way low.

Yes, without a owners manual (remember I only paid 25 cents for it) I am not sure where the contrast is located. However, after watching all the u tube videos, I think I found the correct buttons. At this point, the calculator is DOA. I think I will move to step "B" which is following your guide with respect to the LCD cable.
Thanks

Tom

I too was into electronics in the Air Force. I still maintain a fairly complete shop of electronics instruments and tools. You have introduced a challenge for me which has caused me to do the Ebay thing. I now have 6 83+'s and am commencing to tear into them. The first two I took apart have lithium batteries that are dead.

Continuing to read the manual (yes I bought one of those too off EBay) I read that "all batteries being dead at the same time is catastrophic." This causes me to speculate that if all the batteries were at one time dead, could it cause a DOA?

I know I asked before, but would it make sense to replace the internal battery as a good starting place?

What is the probability of a bad mother board?

If a mother board could be the problem, where do I buy them, and for approximately how much?

I can see where the expense of repair could quickly deter the value of the effort given that I can buy a new one from Staples for $119.
What are your thoughts?

Shrinertom

Very unlikely. This generally just causes them to lose the programs and data you had in RAM. It doesn't affect the EEPROM.

Replacing the AAAs should be enough. The calculators will happily run with no button-cell battery at all, as several of my calculators have demonstrated.

It's possible; I've seen a few calculators with problems I couldn't troubleshoot, where the issue was not the fuse, the LCD, or the keyboard, and there was no visible damage to the board. I find that "bad" motherboards often come from corrosion from battery acid, though.

The only place to get one is from ripping it out of another dead calculator.

Yes, you definitely need to weigh the effort required to repair them, and the cost of your time, versus the cost of the calculator. However, if you have six of them, I'm confident that you'll be able to put together at least a couple of functioning calculators.

Fuse?????

I didn't know there was a fuse.
After I got your message, I immediately got out the manual and look up "fuse" There is no reference to one.
What am I missing?

Thanks

Tom

Like everything related to the internal hardware, the manual does not mention the fuse. There's a surface-mount (SMT) fuse on the mainboard, usually located at the bottom-left when you have the back of the motherboard exposed, next to the positive battery contact. It's a small (but big for a surface-mount component) white elongated rectangle, and can be blown by putting the batteries in backwards or by high current draw.

Now I am ready to dive into the guts.
I can't tell what kind of screw head attaches the back.
I have used the smallest star driver I have
I have tried an Allen wrench
And naturally a small Phillips doesn't work
Am headed for Harbor Freight to try something that will work
What should I be looking for?

The type of screw is a Torx-6, and you can almost definitely find yourself a Torx-6 screwdriver to match it. Helpfully, many cellphones and portable gaming devices use that same screw, so the screwdriver for it isn't that hard to find.

Earlier in our conversation you asked if I had a link cable to a computer.

I don't but can get one if that will help me get started.

How will I use it when procured?

Does the computer software come with it or is it a download issue?

I am guessing that this approach might prove the mother board Pass or Fail without regard to the display. Am I on the right track?

Would you be willing to send me your mailing address. I want to send you something. Send it to Shrinertom@yahoo.com

Thanks

Tom

You'll connect it to each of the calculators (once they have batteries), try to turn them on, and see if the computer software can take a screenshot from the calculator and/or list the files on the calculator.

The TI-Connect software is a free download from http://education.ti.com . You can also use the community-developed TILP software.

You are indeed, the idea is to determine whether the problem is just the display, or the motherboard itself.

Yes, I would; I'll email you my mailing address.

Cable ordered.
When I get it what do I do to check if the mother board is working?

Have downloaded the software but can't continue till I get the cable.

What a treasure you are on this subject.

Tom

While I am waiting for the computer link cable, it occurs to me that the same DOA test could be accomplished by attaching a good TI83+ to a dead unit.

This is did this am by pressing Link (good unit) and found I am getting "waiting." Batteries are new.

Is this a technique that will work and am I performing it properly?

I guess I never told you, but I teach Statistics at UCCS in Colorado Springs. I am trying to change the way Stat is taught. Rather than teaching the students to work problems, I want them to understand the technique, The reason, and interpretation of the results.

I am getting an enormous amount of "pushback" from the department. They think working the problem is the key. I don't agree.

Tom