TI-86 SpeedUp FAQs

Does this work with all TI-86 versions?

Yes, the hardware should be more or less the same.

Where can I find a 1pF capacitor?

Keith L. Miller [miller2@selway.umt.edu] wrote:
I followed a slightly different approach than you pointed out, but basically it was the same thing. I could not find a small enough cap (1pF) so I put two of the smallest I had in series. It speeded up my calculator by about 1.8 times only.
I order electronic parts regularly from Jameco Electronics here in the States, and they do have 1pF caps, but you have to order them in bulk for about $12 U.S. You get 100 or something like that, and I don't need that many, so I think the best thing to do is to just series caps until you can get ahold of one small enough.

Clegg [Clegg@newrock.com] wrote:
I have found that every Radio Shack in the US so far has a pack of caps called a pF pack and it has a very huge amount of misc. caps from 1 to 33pF. (Catalog No. 272-806)

What is the smallest size cap you could use without heating up the CPU to hot?

The heating up is not a problem in this case. I tried to speed up the TI more than 4 times and noticed no heating up, but an increasing error rate.
Using a 1pF capacitor speeds up the TI by about 3 times, and I didn't notice any problem at this speed.

Can I just remove the capacitor?

I don't recommend this but several people have done it on a TI-85. I don't know if it works with the TI-86. Its definitely the easiest solution. However, keep your old C13, just in case... and DON'T bridge the contacts, just remove the capacitor and close the case again, that's all.

Is it possible to use a switch to switch between slow and fast?

I've installed a switch and it worked fine! It's sometimes quite useful to switch back to normal speed especially for assembler programs. Thereby you could save some power too, since the high speed mode needs a bit more power. With the switch you're still able to use the link in slow mode and in high speed mode, this is not possible with the Assembler slowdown:

Another possibility is to use Slow.zip (1KB) or Slow.hqx (1kB) which toggles between fast and slow when launched. With Slow enabled your calculator will run about normal speed but the link works only with Slow disabled (high speed) and you won't save any power with Slow.

Do I have to shut down the TI when switching from normal to fast and back?

Switching in the middle of a computation or game will not effect anything but the speed because there is always a cap connected.

Does the link work, if the TIs run at different speed?

There is no problem to connect a slow to a fast TI, since the two connected TIs chose a speed, which both can support. You will notice that the transmission speed changes if one of the calculators isn't accelerated or if the batteries are low.
However with Slow installed and enabled the link won't work. You have to turn off Slow by starting it a second time.

How can I desolder C13?

This is the way how I do it: Take a small screwdriver (like the one to open the calculator). Heat up one side of C13 (not longer than one second), quickly change to the other side and heat it up, change back and so on while you are trying to push away C13 with the screwdriver. DON'T push too hard and DON'T heat up C13 too long! Do not burn the cable that connects the display board to the main board!

Is it possible to do this with a TI-81?

I had a TI-81 too and in fact I tried to accelerate the TI-81 first (didn't want to damage my TI-85...) The location of the capacitor is on the left side of the main board beside U4. It's named C9 (just like on the TI-85). I included a ASCII-picture, hope it's clear ;-)

Main board:
  +-----------------------------------------------------      
  |                                 C  C C  R11               
  |                                 8 11 9           C7       
  |  ~~~~~~~~~~~~~~~~~~~~          +------------+             
  |  ~                   ~         |            |             
  |  ~                   ~         |            |             
  |  ~                   ~         |     U4     |             
  |  ~                   ~         |            |             
  |  ~                   ~         +------------+             
  |  ~   Batteries       ~                                    
  |  ~                   ~                                    
  |  ~                   ~                                    
  |  ~                   ~                                    
  |  ~                   ~     +----+        +----+           
  |  ~                   ~     |    |        |    |           
  |  ~                   ~     | U6 |        | U5 |           
  |  ~                   ~     |    |        |    |           
  |  ~~~~~~~~~~~~~~~~~~~~      +----+        +----+           
  |                                                           
  +-----------------------------------------------------      
 

I managed to accelerate the keyboard response of the TI-82 too (you have to replace C6 with something between 150pF and 500pF)