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Reset Button Install on TI-99/4A Console

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I recall seeing a post referencing how to install a RESET button on the 99/4a but I cannot find it. I am not talking about the reset on the UberGrom board but the actual console.

 

 

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Momentary pushbutton switch, one side goes to ground, the other to pin 6 on the 9900.

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Momentary pushbutton switch, one side goes to ground, the other to pin 6 on the 9900.

 

Would it be a momentary normally open or closed ?

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Would it be a momentary normally open or closed ?

 

Yes, it's normally open (like it would be without the mod in place). You want a momentarily closed switch as you are momentarily grounding the pin.

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Another way to reset the system is to use the GROM port, by simulating a cartridge insersion when the computer is in use.

- Remove the GROM port inserted on the motherboard GROM connector
- Put it's backside front of you
- Cut the trace on pin #1 where you see the "X" on the picture.
- Solder a wire on trace pin #29 (-5v) and solder a wire on trace pin #1 (RESET) as you can see on the picture
- The reset switch is connected to the two wires.

 

ti99-reset.jpg

 

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Fabrice,

I followed your graphic above back to it's source << HERE >>... nice web page! :thumbsup:

 

... of course I could have just looked at your signature line....

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Yeah great site Fabrice, I'm gonna try to use your Keyboard matrix layout to make a USB keyboard to Ti with an arduino.

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any suggestions of the best place to put the reset switch. I really don't want it sticking out of the top. I was thinking on the right side just before where the speech synthesizer would start if it were plugged in. this place looks to give plenty of room for the push-button switch.

 

I am open to suggestions.

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If I was going to install one, I'd put it on the right hand side on the rear of the computer. This way you would not see it, but it would be easy to reach behind with a finger to press the button.

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I chose to install the reset switch the way that Stuart recommended in the below post:

 

HERE

 

I have also made a step by step you can find in my gallery on my website.

 

HERE

 

It works great!

 

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Hey that's cool. I've never seen that solution before.

I like this approach because a lot of people can get squeamish about soldering on the CPU.

 

 

post-35324-0-97169400-1435037067_thumb.jpg

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Hey that's cool. I've never seen that solution before.

I like this approach because a lot of people can get squeamish about soldering on the CPU.

 

 

 

i tried to post the .jpg file and it told me I was not allowed to post that extension to this community. I must not be special enough!

Edited by Cschneider

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Thank you Ω and Plastik :)
The reset method that I've proposed is very simple. It's an easy solution for people for whom soldering near fragile components scare them or some others who want to keep the motherboard intact or prefer to reduce wires number running across the motherboard.

 

Edit: For people who don't want to make a hole in the computer case to place the reset switch, it's could be interesting to replace the big red LED in front of the 99/4A by a micro-swith with LED integrated (LED pins connected to the power supply and the reset pins to the wires which reset the system).

Edited by fabrice montupet
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Thank you Ω and Plastik :)

The reset method that I've proposed is very simple. It's an easy solution for people for whom soldering near fragile components scare them or some others who want to keep the motherboard intact or prefer to reduce wires number running across the motherboard.

 

Edit: For people who don't want to make a hole in the computer case to place the reset switch, it's could be interesting to replace the big red LED in front of the 99/4A by a micro-swith with LED integrated (LED pins connected to the power supply and the reset pins to the wires which reset the system).

Fabice. Very good solution. I may look into doing it this way in my next reset modification to my F18A console..

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Fabice's comment got me thinking and looking to find a switch that is as close to the size of a standard LED as possible. I found the below, now I just need to think of how to get it to mount on the case in order to use it.

 

View Here

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Fabice's comment got me thinking and looking to find a switch that is as close to the size of a standard LED as possible. I found the below, now I just need to think of how to get it to mount on the case in order to use it.

 

View Here

 

It'll need to be mounted onto a small bit of vero or proto board then have that board attach to something sturdy, the question is what. :)

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It'll need to be mounted onto a small bit of vero or proto board then have that board attach to something sturdy, the question is what. :)

 

that's what I was thinking but I drew a blank of what to mount it to. Guess I will just get a couple of these and see if I can work it out.

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Yes, the simpliest and discret way to fix the micro-switch/LED is to use a hot-glue gun. we don't alter the chassis and, if necessary, it's simple to remove without any scratch.

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Maybe we could find a way to hide a reset button inside the function key or the +/= key, what the hell, maybe we could use a combination of both!!!!! ;-)

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I mounted my reset switch on the left side of the console so I wouldn't accidentally hit it. It's also a relatively flat switch, so it's not real obnoxious. And it's what Radio Shack had that day. :)

 

I also have an observation about the grom port reset switch. I used that method for a while, but it wouldn't reset the console on real severe lockups, I would sometimes have to power-cycle to get back in operation. The 9900 pin 6 method works without fail.

 

Gazoo

 

 

gallery_29515_833_20301.jpg

 

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