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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: redrumloa on December 02, 2008, 04:12:35 AM

Title: A3000T help needed! Jumper settings?
Post by: redrumloa on December 02, 2008, 04:12:35 AM

First off, are these the proper jumper numbers?

(http://i33.tinypic.com/33dk2m8.jpg)

Next, what are ALL the proper jumper settings for a stock A3000T/030? I've jumped out the broken keyswitch and now the keylock light does not go out after pressing it 7+ times, indicating CPU life. I've set the jumper settings to defaults I've found online, but it doesn't post. The computer just sits there with a black screen.

Jumpers anyone?

Title: Re: A3000T help needed! Jumper settings?
Post by: adolescent on December 02, 2008, 04:20:45 AM

And old post from Dale Currie of Amitrix here (http://groups.google.com/group/comp.sys.amiga.hardware/browse_thread/thread/e566c75b4b465951?hl=en).  Looks like your jumpers are correct though.

Title: Re: A3000T help needed! Jumper settings?
Post by: redrumloa on December 02, 2008, 04:22:18 AM

Interesting.. Port analyzer shows no +12V on the parallel port.

(http://i33.tinypic.com/i20eug.jpg)

Actually the power LED is not lighting up either. I didn't think of it much before, thinking maybe it was the LED itself. Now I am more concerned. Looks like I will have to take a closer look at the power supply.

Title: Re: A3000T help needed! Jumper settings?
Post by: redrumloa on December 02, 2008, 04:33:57 AM

Power supply... hmmm.. everything looks ok except FAIL, I get ~1VDC. There should be +5VDC on fail? Right?

Title: Re: A3000T help needed! Jumper settings?
Post by: Castellen on December 02, 2008, 05:09:37 AM

Yes, FAIL is active low and is an indication to the system that the 5V supply is above a specific threshold.  So it should normally be at 5V.  As I recall, it goes to Gary which holds the system in a reset until FAIL changes to a high state.  The source of the signal in the A3000D is U112, it's a 3-pin IC in the TO-92 package.  Can't remember if it has the same designator in the A3000T.

There's a pull up resistor on the FAIL line already, so if you remove U112 and the signal changes correctly to the high state, then you need to replace U112.  Else look at the signal path to Gary and at pin 2 of the RTC.  If there's been battery corrosion, this could be what's causing the problem.

You can also set the FPU jumper (J103?) to disable the FPU, which will prevent the system from booting if it has a problem.

Title: Re: A3000T help needed! Jumper settings?
Post by: redrumloa on December 02, 2008, 01:06:34 PM

@Castellen

Good stuff, thanks!

Title: Re: A3000T help needed! Jumper settings?
Post by: redrumloa on December 02, 2008, 07:50:06 PM

I've tested jumping out fail with +5vdc and now I get a power LED and I get a cycling yellow screen. I wonder if the CPU is dead.