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Is there any hope for this old calculator (stiff slide switch)

Is there any hope for this old calculator (stiff slide switch)


  #1  
Old 05-10-20, 07:38 PM
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Question Is there any hope for this old calculator (stiff slide switch)

When I was a little kid my Grandmother (now passed) gave me her prized calculator a Texas Instruments TI-1250.

I just found it while looking for something else (you know how that goes, I found the calculator but not what I was actually looking for I will find it next time I look for something but not what I was looking for that time).

It works fine and the battery cover was lost before I got it, anyway the problem lies in the power switch.

It is one of those old slide style switches, the switch is very hard to move by hand I actually need a little flat blade screw driver to get it to move it is that bad.

Is there a way to lubricate or make it easier to move from on to off and back?

Thanks
 
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  #2  
Old 05-10-20, 09:04 PM
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I see some rust inside switch. Spraying with WD-40 and moving the switch back and forth will loosen up those rusts and allow the switch to move easier. However, doing so will also melt away any grease that may remain inside switch and eventually make it tough to move again. (WD-40 will slowly evaporate)
If you want to actually restore the calculator, you might want to disassemble the switch and properly remove rust inside and lubricate. They may have used some standard off the shelf switch in that calculator, so it might also be possible to replace the switch.


Just googled picture of the circuit board, and it does look like they have used standard off the shelf switch. I'm your you can find a replacement switch. I cannot tell exact size and number of legs of the switch from the picture, so you will have to take it a part and look for a replacement switch.

I'm sure one of these switches will work.
https://www.mouser.com/Electromechan...lide-Switches/
 
  #3  
Old 05-11-20, 04:37 AM
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WD-40 will likely help. However I would not 'spray' it. A few of drops is likely all you need.
 
  #4  
Old 05-11-20, 04:43 AM
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I am sure the operation of the switch can be improved, but you must decide if the cost of supplies and labor is worth it compared to purchasing an equivalent new one for under $10 . To fix yourself, purchase a aerosol can of TV contact cleaner/lubricant. Spray contact cleaner into switch opening. Operate switch. If not improved continue with following. Remove the case which is 2 pieces held together by screws.. If the screws are not visible, check battery compartment or under rubber pads on bottom of case. Thoroughly clean internals using small paint brush and a vacuum. Spray switch and operate. Reassemble. I think this is the best you can do unless you can get a replacement switch and install yourself. Good luck. By the way, I have a TI Programmable 58 I keep around to show my grand-kids when they get out their TI-84. Good luck.
 
  #5  
Old 05-26-20, 03:43 PM
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OK I got side tracked (you know how that goes Lol!)
Anyway here are some pictures of the inside, it looks like a standard off the shelve slide switch. I suck at soldering on circuit boards and I don't want to ruin the calculator. I do have WD-40 and some 3-in-one oil (both types the red bottle and I also have the blue bottle that I use for my electric fans/motors)
 
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  #6  
Old 05-26-20, 04:25 PM
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Not 3-1. That is oil. WD40 is a cleaner. Use that. Just needs 2-3 drops and work the switch back and forth.
 
  #7  
Old 05-26-20, 05:19 PM
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Back in action!

Thanks that worked joed I sprayed 1 spray in each position and I worked the switch back and forth, and now it feels like new again.

I also think these products with the new "smart straw" as WD-40 puts it are not so smart I liked the old system the same with Caigs De-Oxit spray and their new dispenser system.

I actually waste more product then I did with the old system, luckily I don't mess with audio systems that much (I have mostly newer stuff, save for my old Technics turntable I love vinyl!) anymore
 
 

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