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AuthorTopic: Amiga500 Reset button  (Read 388 times)

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Offline brostenen

Amiga500 Reset button
« on: September 30, 2019, 07:39:36 PM »
Hi all.
I have copied my question/post, from another forum. Yes I know. I am just a tiny bit lazy and did not want to write it all again. :-D

Let me start my question, by saying that I am noob in reading schematics. Yet I have a tiny question on if I am reading the schematics correctly.

I have this project, in were it would be so awesomme, if I was able to add a reset button to an Amiga500 board. Now, I thought that it was not possible, and that the Amiga 500 was only able to do hardware reset by doing it on the keyboard. Yet now I am really not sure if that is an urban myth or something.

Well...
I was looking in my 500 manual for a different reason, and I thought that it would be fun, just to look at the schematics in the back of the book. And on the first page, there is a mention of JP1, being the jumper for system reset vs keyboard reset. Then I looked at the 7th page of the schematics, in were the JP1 is found. It was marked as going to "_kbreset" and finally on the 6th page, the "_kbreset" is actually Pin6 on the connector for the keyboard.

Well...
That was a bit interresting I thought, and I found a picture of an Rev6a board that I have, and found the actual JP1 right below the transistor a bit to the right from were RESET is on the silk screen. And sure enough, the jumper is bridged by a solder blob.

Now. If I remove the solder blob, and solder in a couple of jumper pins. Would this be possible to insert a switch from a PC-Case and if the switch is a momentary off switch, then I would actually be able to use both the switch and the keyboard. Are my reading of the schematics correct?
 

Online TribbleSmasher

Re: Amiga500 Reset button
« Reply #1 on: September 30, 2019, 07:52:26 PM »
Usually you have to pull the kbreset line to ground. Make sure you use a pushbutton that clicks, to make a proper connection when hit.

Look over here (it is in german but has pictures).
https://www.amigaworld.de/workshops/reset-am-amiga/
 

Offline brostenen

Re: Amiga500 Reset button
« Reply #2 on: September 30, 2019, 11:05:34 PM »
Usually you have to pull the kbreset line to ground. Make sure you use a pushbutton that clicks, to make a proper connection when hit.

Look over here (it is in german but has pictures).
https://www.amigaworld.de/workshops/reset-am-amiga/

Cool... Well... German is not a strange language to me. Though I am from Denmark, then I grew up with German television (back then we only had one single Danish channel, yet we had: ARD, ZDF and N3 from Germany), and I learned German in primaery school as well.

Hmm.... I would much prefer the JP1 aproach, if that is a solution that works. It is for my Amiga500 case convertion, and adding jumper pins to JP1, seems like a cleaner result than adding wires to a chip. I can always insert a jumper on the pins, until I get the button solution worked out.
 

Offline psxphill

Re: Amiga500 Reset button
« Reply #3 on: October 01, 2019, 03:56:26 AM »
Now. If I remove the solder blob, and solder in a couple of jumper pins. Would this be possible to insert a switch from a PC-Case and if the switch is a momentary off switch, then I would actually be able to use both the switch and the keyboard. Are my reading of the schematics correct?

I may be wrong, but my reading of that schematic is that breaking jp1 and soldering a switch across it would would cause the power on reset to only work if you held your button & the button would only work during power on.
 

Online TribbleSmasher

Re: Amiga500 Reset button
« Reply #4 on: October 01, 2019, 06:14:28 PM »
You dont need to wire to a chip. Follow the signal to a better spot on the board.  i just dont have the schematics at hand.