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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Roger_S on May 24, 2008, 05:16:29 PM
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Hi all,
I received my A2000 today. I had to change the PSU due to fire hazard.
The original PSU has been swapped with an AT PSU. Was an easy job. All pins are connected except the TICK signal, wich should be fine as I don't use a FF or VGA card.
I swapped J300 from pin 12 to 23 (Jumper located above Paula)
I booted the A2000 but now find to see that I have a blurred screen, Workbench boots fine. I don know if it had the problem before as I didn't boot it with its original PSU.
The monitor works fine on my a1200 and is connected using the "scart" connector.
When I move the J300 back to 12 the miggy seems to keep rebooting in a loop, no FD activity.
Any ideas?
Regards
Roger
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Anyone?
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The Hawley-Smoot Tariff Act
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I could really need some help on this one.
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Try to change the capacitors around the Video Slot
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Do you mean the elco's around the Zorro Slots? They all seem to be fine.
Has the distortion something to do with my repairs?
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Hi Roger_S,
It's not working with J300 set to 1 and 2, because that selects TICK signal from the PSU (mains frequency). It "should" be working set at 2 and 3, though AC TICK is probably best.
Sorry if this is stating the obvious, but did you try re-seating all the socketed chips? (I once had an A500 with screwy video, re-seating Paula cured it.)
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I'd try cleaning the video port.
is a1200 working with same cable?
have you tried composite out?
you should have either scart or composite connected to one monitor (never both at same time)
there are some fuses for video port on motherboard, maybe worth checking.
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I reseated all chips. I haven cleaned the port and the A1200 is using the same cable and monitor.
composite is gray and the screen is scrolling every 5 seconds.
I'll check the fuses if i can find any.
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the composite is supposed to be gray, but is it blurry?
the fuses are green and they look like resistor (but covered with solid green). they are for +12V (and maybe +5V) line, probably not the cause but worth to check as they usually break.
I think you should post a photo of blurry screen..
are you using same screenmode on A1200/A2000? games?
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http://img228.imageshack.us/my.php?image=img0426bs5.jpg
it is not the camera that is unfocused. The whole screen looks like this.
The compsosite screen scrolls every 5 seconds. It shouldn't be doing that.
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Very weird - I'd have expected a grounding problem, but that would only smudge the output horizontally, not vertically.
Are you sure that the monitor is AOK?
Have you tested the exact same input to be good?
Is the output stable or maybe jittering (very fast)?
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No jitter, as I mentioned the composite output is scrolling every 5 seconds, that doesn't seem to be right.
Also the monitor works fine with my A1200.
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I have no idea what could cause that. but it looks cool to me ;)
do you by any chance have Amber card or similar scandoubler? (to see if its output is blurry too)
any gfx card?
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I Have a Picasso II in my Amiga 1200. But as I changed the PSU from my 2000 I now have no TICK signal. No SD or VGA will work anymore.
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With a non-Amiga PSU you'll need to set J300 to 2-3 (A500 tick/_VSYNC).
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Do you mean the elco's around the Zorro Slots? They all seem to be fine.
You need a true tester to check them ! they could be nearly 'dry' internally...
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Than it is not easy for me to test the functionality. I'll just exchange them with same type.
What if I would change all the video chipsets, like Agnus and denise, could that help?
@zac67, The jumper is set to 2-3, but I thought/read that no SD of VGA card would work anymore.
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@Roger
J300 determines where the _TICK signal for one the CIA clocks comes from. Usually it's derived from mains frequency (thru the PSU), on the A500/1000 they use the video's vertical sync which is cheaper - but with ECS you can change the vertical frequency which will make the clock unreliable. If you don't use 'custom' video modes, it shouldn't matter.
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OK, I'm going to try my picasso II and a different monitor that I can hook up to the RGB port.