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Author Topic: Amiga 2000 a-model power supply (to PC supply conversion)  (Read 2358 times)

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Offline arttu80Topic starter

Amiga 2000 a-model power supply (to PC supply conversion)
« on: September 06, 2007, 09:10:58 PM »
Greetings from Finland!

I have problem with my A2000 power supply, it doesn't seem to work anymore. I know it is possible to change few little parts in it, but I wanted to try PC atx -type supply. I already installed and tried it, but my dear Amiga only flicks gray and white :-o  (with power led flickering at about 1/second rate)...

I know it must be that TICK signal, which isnt there in PC power supply..sooo, how can I bypass it? I know its quite easy on B2000 by changing jumper position, BUT on this rev 4 motherboard?!?

I will appreciate any replies!
 

Offline hamtronix

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CD TV / Remote / Trackball Remote / Keyboard / CDTV 1411 External Drive / C= 1405 256K RAM / Smell the fear!
 

Offline arttu80Topic starter

Re: Amiga 2000 a-model power supply (to PC supply conversion)
« Reply #2 on: September 07, 2007, 03:59:47 PM »
Well, thanks for reply, but I specificly meant A2000 motherboard, there is no jumper to use internal clock?

So only option is to make TICK generator as per original PSU???
 

Offline Andeda

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Re: Amiga 2000 a-model power supply (to PC supply conversion)
« Reply #3 on: September 07, 2007, 08:26:49 PM »
You need to change jumper J300 to cover pins 2-3, so that the TICK signal is provided internally by the VSYNC signal.
And it works fine in my A2000  :-)
Amiga: A computer for the creative mind.

Sam440ep 667Mhz + OS4.1
Minimig (Home made)
A1200/030
A2000/030
A500 * 3
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Offline Andeda

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Re: Amiga 2000 a-model power supply (to PC supply conversion)
« Reply #4 on: September 07, 2007, 08:35:57 PM »
sorry, i did not read from the beginning, so you dont have this internal opportunity. then you just have to build a external tick generator, there was a discussion about this some time ago.
Amiga: A computer for the creative mind.

Sam440ep 667Mhz + OS4.1
Minimig (Home made)
A1200/030
A2000/030
A500 * 3
CD32
 

Offline rkauer

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Re: Amiga 2000 a-model power supply (to PC supply conversion)
« Reply #5 on: September 08, 2007, 02:31:41 AM »
 You can use this hack:rtfm:

Goodbye people.

I\'ll pop on from time to time, RL is acting up.
 

Offline arttu80Topic starter

Re: Amiga 2000 a-model power supply (to PC supply conversion)
« Reply #6 on: September 08, 2007, 11:55:34 AM »
Thanks to all for replies.

rkauer:

I'll try out that hack! Thx.  :rtfm:
 

Offline Zac67

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Re: Amiga 2000 a-model power supply (to PC supply conversion)
« Reply #7 on: September 08, 2007, 12:11:55 PM »
Alternatively, you could just connect Agnus' _VSYNC output to the _TICK signal - that's what J300 does.
Using _VSYNC as _TICK raises problems when you change the vertical scan rate, but the OCS Agnus can't do that anyway.

You'd probably want to disconnect (=cut) the appropriate trace to the PSU to make sure _VSYNC and PSU _TICK are isolated.