Released 1995, identified by word TI-92 labeled on upper right corner of the screen

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Why is the cursor difficult to press left and down?

Thank you for your time,

I bought an un used ti-92 plus. The cursor pad requires significant force for down and left, but nicely clicks for up and right.

Any help from your experience is very helpful.

Thank you for your time,

- Erik

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Chosen Solution

The conductive "paws" on the silicone button membrane where not landing flat onto the logic "prints" on the circuitboard.

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This is do the design of the D-pad button. It pivots about the origin, therefore "tilting" the "rubber button/paw", which causes the "paw" to not land flat. Landing flat is important to cause continuity across the "print".

Thus,

By modifying the D-pad, one can cause the "paw" to land flat. The idea is to "pitch" the buttons interaction with the D-pad, so that, by the time the "paw" rotates down, it lands flat on the "print".

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  • Last note: Applying small amounts of silicone grease (Plumbing Section), allows the rubber "paw/buttons" to slip in the interaction against the epoxy and slop into its natural flat position. Silicone grease will not eat the plastic like normal grease would.

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** The silicone grease is to go between the epoxy and rubber pad. No contaminates should be on the chip side at all.

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Most Helpful Answer

Hi,

The contacts for the left and down cursor may be dirty. Being an un-used device they shouldn't be worn out.

Here is a link to the ifixit repair guide for the device.

Here is an image taken from the repair guide. I have highlighted which contacts need to be cleaned, both on the board and on the rubber pad. (The rubber pad contacts have a conductive coating which bridges across the contacts on the board, when the button is pressed down completing the electrical circuit)

Use a Q-Tip moistened with IPA 90%+ (Isopropyl Alcohol - available at most pharmacies - do not use 'rubbing alcohol' as it is not as effective)

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(click on image to enlarge for better viewing)

Take note of the caution issued at Step 9 in the ifixit teardown instructions

Alternatively since you stated that you bought an un-used device, did it come with a warranty at all?

If so follow up on getting a warranty repair or replacement as by trying to fix it yourself as shown above, will void any warranty.

Hopefully this is of some help.

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Thank you Jay for your quick response,

The blue cursor button is designed incorrectly. I developed a method to correct for the aberrations. It works wonderfully now.

(If I have time, I might open the calculator back up in two weeks and show pictures of what was done. ) Should I wait till then to post my answer?

Thank you again for your kind response, and what a professional site,

- Erik

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The site is professional indeed, as well as the iFixit team. But the answers are all from volunteers, none of them employed or affiliated with iFixit. Sometimes an iFixit team member will venture here and answer questions, but as a volunteer as well. Not on company time.

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Hi Erik Bryson,

It would be of benefit if you 'answered' your question showing if possible pictures as well. Here's how to add pictures.

That way in the future anybody else who is experiencing the same problem will derive the benefit of what you have found out and done.

Alternatively you could create a repair guide for the device

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Thank you Jay,

Will do in the next week.

- Erik

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Erik Bryson will be eternally grateful.
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