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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Rejak on December 29, 2002, 04:10:44 PM

Title: A3000 powers up, blank screen
Post by: Rejak on December 29, 2002, 04:10:44 PM
 Everything powers up ok (HD, Floppy, etc.), but nothing on the monitor screen. Not even a slight screen refresh!! Just black screen. All RAM is ok and has been tested (four times!). CPU? ROMs?
 :-?
Title: Re: A3000 powers up, blank screen
Post by: on December 29, 2002, 04:28:18 PM
Have you tried it on a different monitor?
Title: Re: A3000 powers up, blank screen
Post by: Rejak on December 29, 2002, 04:33:25 PM
Oh yes.  When powering up, the monitor light does come on, and goes off when I power off.
Title: Re: A3000 powers up, blank screen
Post by: Castellen on December 29, 2002, 07:27:00 PM
To be honest, it could be almost anything.
Depending on how far you want to go, how much digital electronics
knowledge you have and what test equipment you've got.

A good starting point is to make sure the +5V and +12V supplies are
running, you can test that with a multimeter.  But since the hard
drive is working, they're probably OK.

Make sure all the ICs are seated correctly in their sockets.
Check that the ZIP memory are all in the correct sockets and none of
the legs are bent on a weird angle.

But from then on you'll be guessing.  Look for anything visible first,
like corrosion around the RTC battery.
Next you could try swapping parts between a working computer and see
if you have any luck.
An A500 uses the same pair of CIAs, Paula, Denise and Fat Agnus.

After that it's time to get out the oscilloscope and start looking for
a fault on the shared 32 bit address/data bus.
Good luck!
Title: Re: A3000 powers up, blank screen
Post by: N7VQM on December 30, 2002, 01:25:48 AM
Have you tried both video outputs (Amiga and VGA)?
Title: Re: A3000 powers up, blank screen
Post by: QuikSanz on December 30, 2002, 01:30:54 AM
As I recall the 3000 uses a super denise. A bit diferent.

Chris
Title: Re: A3000 powers up, blank screen
Post by: Kronos on December 30, 2002, 01:39:48 AM
@QuichSanz

Both versions of the Denise are pin-compatible, so you can put an
old one into an A3000, loosing the SuperHighRes-based resolutions,
or but the ECS-version into an A500 making it half an A500+.

The A3000-Agnus on the other way may be the only version that works
in an A3000, but I never checked.
Title: Re: A3000 powers up, blank screen
Post by: sarkis on December 31, 2002, 01:21:56 AM
1 what type  of monitor?
2 Graphic Card?
3 press on all chips
4press on both mouse tabs to bypass start up sequence..see if monitor works?
5. roms 3.1?
6soft kick
 :-o  :-o  :-o  :-o
Title: Re: A3000 powers up, blank screen
Post by: sarkis on December 31, 2002, 01:27:06 AM
dumb...but all cables ok and connected...
theres a switch on the back by the vga socket..
flick up and down?
test monitor on another amiga..
boot of floppy with workbench
sarkis :-?
Title: Re: A3000 powers up, blank screen
Post by: sarkis on December 31, 2002, 01:28:37 AM
hard drive aint working??????????? :-?  :-?  :-?  :-?
Title: Re: A3000 powers up, blank screen
Post by: N7VQM on December 31, 2002, 03:45:16 AM
Quote

sarkis wrote:
theres a switch on the back by the vga socket..
flick up and down?


Flip that switch down to enable the VGA output.
Title: Re: A3000 powers up, blank screen
Post by: Rejak on January 02, 2003, 12:33:56 PM
SVGA monitor, onboard video, monitor DOES work, it's on a 4-gang switchbox with other computers that work, yes ROMs 3.1 on a tower.
Title: Re: A3000 powers up, blank screen
Post by: Rejak on January 02, 2003, 12:34:43 PM
Yep, all that and more checked.
Title: Re: A3000 powers up, blank screen
Post by: Rejak on January 02, 2003, 12:36:11 PM
Hard drive works fine. IT IS A MOTHERBOARD issue for sure (believe me, I'm a tech, just not real familiar with Amiga stuff and don't have a board schematic).
Title: Re: A3000 powers up, blank screen
Post by: Rejak on January 02, 2003, 12:36:51 PM
Yes, I know what the switch is for....
Title: Re: A3000 powers up, blank screen
Post by: blobrana on January 02, 2003, 01:35:53 PM
Well, i think your gut feeling isright ,

But just to make sure , you have tried to boot from a floppy ( you may need to strip down the expansions).

I have seen problems like this due to incorrect 040 Librarys or software conflicts.

Also ,on a cheery note, the MOUNT command ( or similar) could be infected by a virus.

Good luck.
Title: Re: A3000 powers up, blank screen
Post by: N7VQM on January 03, 2003, 07:32:01 PM
Quote

Rejak wrote:
Hard drive works fine. IT IS A MOTHERBOARD issue for sure (believe me, I'm a tech, just not real familiar with Amiga stuff and don't have a board schematic).


Too bad you're not in Kansas City, I'd let you borrow mine. 8-/  However, what your A3k is doing is exactly what mine does when my CSPPC gets loose on the Fast slot or it eats a SCSI3->SCSI1 adapter.  
Title: Re: A3000 powers up, blank screen
Post by: sarkis on January 03, 2003, 09:16:07 PM
have you tried to bypass the start up sequence by
holding down for a while on both right and left mouse buttons at the same time? you do this on initial power on....... :-D  :-D  :-D  :-D  :-D