TI-85 SpeedUp FAQs

Does this work with all TI-85 versions?

I'm using a TI-85 with ROM version 5.0, but I accelerated one with version 9.0 too. The hardware is more or less the same. This procedure should work with all TI-85 versions!
However somebody reported a problem with a very very early version of the TI-85 (model no. 0833992 I-0892) ROM version 3.0. My calculator has model no. 1002861 I-1092 so any number bigger than mine should work anyway.

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 tried this too. It's faster but not as reliable as with a 1pF capacitor. If you remove the capacitor, DON'T bridge the contacts, just remove the capacitor. With no capacitor the possibility of a crash is much higher! However several people reported that their calculator worked very well without any C9.

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.

Another possibility is to use Game Wizard ( Bin Hex 17kB) or Game Wizard (Zip 24kB) which works on most ZShell games so far and is much more stable than Turboslow. (all games except those with gray scale) However with GameWizard you won't be able to save any power.
You can slow down the game (useful when cheating, but also if you've turboed your calc without a switch) and crash back to ZShell if the game is caught in an endless loop. And it lets you change lives, starting level, score, ammo and much much more.
Actually, you can use it for other purposes, like debugging too. If you can't understand what's wrong in your program, you can keep track of the temporary variables with Game Wizard too.

To slow down a game, install GameWizard and start it (it will read activated. If not, exit and start it again). Press On+Enter, from the menu select "Game Playing Speed" (use the down arrow but just press the buttons VERY shortly!!!) press Enter. Use the up arrow to set a delay from 0 to 9 (0: fast, 9: slow). Press Enter, Exit, Enter to get back to ZShell. For more information about GameWizard refer to the enclosed documentation (please don't e-mail me)

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.
The computer link from Texas Instruments works too, however Pasi Lassila (pas1@freenet.hut.fi) told me that he had problems with a turboed TI-85 and the parallel link (this is the only report I have about problems with links and accelerated calculators).

Does ZShell still work with an accelerated TI-85?

Some ZShell games don't speed up with turbo. One of them is ztetris. Maybe it uses some other timing for speed than other games.
Zpong and some other 2-player link games doesn't work if only one of the calculators is turboed.
Some gray scale games halt with turbo. Luckily not Daedalus. It's great with turbo.

How can I desolder C9?

This is the way how I do it: Take a small screwdriver (like the one to open the calculator). Heat up one side of C9 (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 C9 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)