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Old 25 March 2003, 09:20   #1
th4t1guy
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This is why I love the A4000...

I opened the thing up to change the jumper on the board so it would boot up in PAL, (there's a jumper for NTSC or PAL mode) when I noticed all the pins were in a row, and I had an extra switch on my case. Now all I have to do to change between PAL and NTSC is press the turbo button! No messing about with the mouse.
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Old 25 March 2003, 10:46   #2
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Yeah, I did this bit with my A2000 (and my A500), only I skipped the switch part because I found I had no use for the NTSC mode.
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Old 25 March 2003, 14:27   #3
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NTSC gives a slightly faster clock speed for the A500 - maybe for the A600/1200 as well.

th4t1guy, you say you press the 'turbo' button?!? which A4000 case is that one on mine's still in its desktop case, but I've just finished 2 weeks contracting and I'm thinking of towering up - trying to find a case were the slots run verticaly! Oh well I'll have to get the dremel out and hack it as usual or if any one's got/can get one of the zorro adapters that lay them over, let me know!

Anyone know a case available in the UK (not the Z4 power job) that'll take the A4K without too much work?

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Old 25 March 2003, 21:54   #4
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syko:

I picked up one of those huge AT tower cases at a computer show for about $15, and followed an online guide to put an A4000D in there.

I had to dremel a large chunk out of the back, and I had to take a few parts from the original desktop (the motherboard connector, the metal bit where you screw the zorro slots in, and the bar that run on top of the zorro card. There are three buttons on the case. A power button, a turbo button and a reset button. The turbo button was perfect for a PAL/NTSC switcher, but the reset button is currently useless (unless anyone has an idea? ).
Right now I'm hoping that if I get a mediator card, I will be able to fit it in my tower case, since there's no way in hell I'm spending some unGodly sum of money on the cases being sold by Software Hut. I'll buy a bunch of legos if I have to! :P
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Old 25 March 2003, 22:12   #5
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you could have it as a working reset button...
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Old 26 March 2003, 00:17   #6
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Is there a jumper on the board for reset? I looked and didn't find anything.
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Old 26 March 2003, 04:11   #7
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Quote:
Originally posted by Syko
NTSC gives a slightly faster clock speed for the A500 - maybe for the A600/1200 as well.
There is a 14% speed increase, on an A500, A600, Commore 64 or whatever

But shitloads of programs do not work in NTSC mode.
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Old 26 March 2003, 04:58   #8
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If I remember right, I've a few NTSC games that don't work right in PAL mode. Plus the fact that in a lot of games, the speed of the music changes.
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Old 26 March 2003, 05:45   #9
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Quote:
Originally posted by th4t1guy
If I remember right, I've a few NTSC games that don't work right in PAL mode. Plus the fact that in a lot of games, the speed of the music changes.
Yep, they are the less of them, but they exist.

I wish I had such a hardware mod done on my A600
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Old 26 March 2003, 08:16   #10
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All of the big box amigas had pal/ntsc jumpers. I'm sure this was for production cost reasons (same reason the power supplies can switch to 220V). I added a switch to my A3000 many years ago. I usually ran PAL because of the slightly higher resolution. On the VGA you don't notice the flicker.
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Old 28 March 2003, 16:42   #11
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th4t1guy:

thinlega is dead right, it is possible to use the reset button as a h/w hacked Ctr-A-A equivalent, planning on doing it to mine, once I've transposed the instructions for doing it to an A500 to match the A4000D.

Which online guide did you use to tower it?

I've got a full tower AT case which I've had the A500+ set up in (with the GVP series II pushing it up the case), but it's kinda hacked about, so I might try to get a new one! Either that or buy some new cutting disks for the dremmel

One other question, the hard drive activity light on my A4KD is always on, anyone any ideas for getting it to work again?
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Old 28 March 2003, 17:03   #12
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cool gotta find those jumpers
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Old 28 March 2003, 23:36   #13
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http://home.c2i.net/ghisdal/a4ktower/

and

http://home.arcor.de/tbraeuti/Computer/SelfATower.html

A few tips:

1) You'll want to spend a lot of time thinking and planning about how you're going to do everything. You'll also most likely end up having to take a few parts from the original case so that it can hold together.
2) Before you drill or dremel anything, measure and actually try to fit the hardware in there first. When I did my tower conversion, the motherboard would not fit with the harddrive rack, and it would bump into the processor. I eventually removed the rack and mounted it about the power supply.
3) If you screw up, remember. Epoxy is your friend. (but it can also be a nightmare. make sure your epoxy is 100% dry before you get any hardware near it!)

As far as the hardrive LED goes...it sounds to me like the wires are probably reversed or something.
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Old 29 March 2003, 15:19   #14
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Na it's not the connection, coz if I reverse it, the LED wont light up at all.

I could connect to the drive directly, but I'd like to avoid that if I can
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Old 29 March 2003, 15:40   #15
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Thanks for the links, I've got em saved for reference & my full tower case is going under the knife this week! Hack, slash, kill, modding cases is such fun
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Old 30 March 2003, 03:05   #16
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i'd try and avoid reversing wires on leds
ive heard wrong polarization can kill them any leds that is
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Old 31 March 2003, 15:36   #17
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Na, all LED's are just diodes - they only pass current one way. So if they're connected wrong way round they wont light up. BUT it is possible that a badly designed driver circuit could have a problem with it, so not a good area for experimentation, about the only thing that kills LED's is having too much current run through them, and that's usually because you made a cock-up with the limiting resistor...

If I knew the signal path for it from the harddrive I could trace it to see where the problem is. But I would need full tech spec for component level access - anyone got a copy? small chance I know.
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Old 31 March 2003, 20:20   #18
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well if you say so
still i think i asked one day in electronics class
could leds be used like other diodes ? and have some light show as a bonus
the teacher said these diodes aren't meant to be used like diodes and too much current in the wrong direction would fry it
still maybe if we're just switching the same current it's always been using around just nothing happens

bah what do i know
i hate electronics class
too much math
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Old 01 April 2003, 16:53   #19
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max forward current is usually about 10 - 25 mA, which occures with about 1.5V across the junction, so for 5V supply that requires you to drop 3.5V @ 25mA.

Using Ohm's law where V=IR, gives V/I=R so;

3.5/0.025= 140 Ohms

easy peasy and if it's wrong feel free to shoot me, havent bothered checking it and this is the first time in over 12 years I've used it

Real reason is that a reverse voltage of much more than 25V will blow most LED's (VRmax). BUT as long as the voltage is less than this (and it should be!) then they'll be fine.
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Old 01 April 2003, 16:59   #20
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Oh and to answer your question hal, yes they can be used exactly like any other diode as long as you dont exceed their tolerances - which are a lot less than ordinary diodes... 1N4001 will handle mains voltages no prob, a LED would vaporise! I know, I've tried it, try not to be as stupid as me
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