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Author Topic: A2000 psu and keyboard  (Read 1929 times)

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Offline orange

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Re: A2000 psu and keyboard
« on: July 15, 2006, 01:02:14 PM »
I had exact same "tick" problem with A2000 PSU, so I replaced it with ATX.

The infamous TICK signal doesn't exist on PC PSUs. You can make one
or put jumper:

Quote
J300   This jumper determines the time base used for the 50/60Hz CIA
   timer chip.  In the normal position, the 50/60Hz TICK clock,
X-X X   based on AC line frequency, is used as a time base.  In the
   alternate position, the vertical sync pulse from the video
   section is used.  The system will not operate properly
   without one of these clocks.


warning: I'm not sure if its J300, there is some false info about that on net.

The S_user, IIRC is just +5V for mouse, but I'm not sure so check it.
dont know about KEY, maybe "empty pin" to make sure you don't put power connector wrong way.


no you cannot use PC keyboard without adapter, look at the one on site I mentioned.

PS. I used 300 W Chieftec, works like charm.
Only had to drill a hole in it to fasten to Amiga case.
“Giving up is always an option, but not always a failure.”
 

Offline orange

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Re: A2000 psu and keyboard
« Reply #1 on: July 15, 2006, 03:34:08 PM »
its somewhere below power supply, near right CIA chip, in top right corner looking at front of A2000, just above Paula.
No need for any software to run ATkeyboard adapter. You got Protel ready schematics on my site that 100% works, and aminet link to adapter. It works very nice.
You might have some slight problems in some games. Somehow it seemed to me there is slight delay (but it could be just me
 :roll: )

If you don't make Tick yourself, you can't use some Genlocks and clock might be slightly less accurate, but otherwise it will work great.
“Giving up is always an option, but not always a failure.”
 

Offline orange

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Re: A2000 psu and keyboard
« Reply #2 on: July 15, 2006, 03:39:41 PM »
Dont forget, you need to be checking (switching)power supply ALWAYS with some LOAD, otherwise its likely to not start at all or sometimes even break. ( I use 12V car lights)

I have been trying to find someone to repair Amiga PSU for years with no success. Everyone suggests its much safer to replace it, because when it fails usually several components inside PSU die.


 :-(


PS. I have seen very cheap A2000 PSUs on ebay but problem might be expensive postage..

and don't forget that PSU capacitors have dangoerous voltages even after being disconnected for long time
“Giving up is always an option, but not always a failure.”