Corrup A3000 interlaced display on LCD monitor

SJBUK

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Here we go, reckon it's an A3000 hardware problem?
I can get 640x256 PAL or 640x200 NTSC up fine on an LCD monitor but this is what happens when I switch to interlace...
 

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Kin Hell

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Re: Corrup A3000 interlaced display on LCD monitor

What other hardware (add in cards) do you have & what is in your Devs:Monitors drawer??

Kin
 

SJBUK

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Re: Corrup A3000 interlaced display on LCD monitor

No expansion cards. Have 4Mb fast, 2Mb chip. KS 37.175 WB 38.12.

Hmm, have nothing in Devs:Monitors. Do I just copy from Storage:Monitors? It's been a while, I should read up on it i guess!
 

Kin Hell

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Re: Corrup A3000 interlaced display on LCD monitor

Storage:Monitors is where you need to drag the relevant Icons from, for the Display you are wanting to display; - And they need to be in your Devs:Monitors drawer!

If you are Kick-Starting anything & emulating the ROM above the capabilities of your, at Best ECS A3000, then yeah, you're gunno see cr4p! :)

Can an A3000 run a Double Pal Screen Mode?? - I would think not!

What is your A3K booting?

Kin
 

SJBUK

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Re: Corrup A3000 interlaced display on LCD monitor

Kickstart 2.04 in ROM, running WB 2.1 off of HD.

I was always under the impression it would run interlace dmodes fine on a 31K monitor.

Will keep plugging away :D
 

TheCorfiot

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Re: Corrup A3000 interlaced display on LCD monitor

@SJBUK

Is the A3000 running on an original A3000 PSU and if so check the "Tick" reference on the motherboard is set to ext (or PSU) not internal chipset derived. The Tick select is a jumper on the motherboard.
And out of curiosity is your A3000 a pure PAL model or an NTSC model with the motherboard jumper set to PAL..

The display you posted reminds me of an A2000 which had been modded to run with an ATX PSU & the Flicker fixer refused to work properly anymore as the Tick signal had to be derived from the chipset because the ATX PSU did not generate it...

We will keep trying to help, If you can just borrow a CRT monitor for an evening of testing it would be good to eliminate it from our fault finding.

TC 8)
 

SJBUK

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Re: Corrup A3000 interlaced display on LCD monitor

Thanks guys, will have another stab tomorrow. I'll start by locating the jumpers and checking whats what, think I'll need to strip the system down a bit more.

The A3000 is a 240V PAL machine.
 

rkauer

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Re: Corrup A3000 interlaced display on LCD monitor

Maybe it's time to check memory, too.

Flicker fixing is a matter of storing a "half-frame" on memory, then combine it with the next then send the result to the output twice and start again.

If the dedicated memory develops a fault, you see the results (like the image you see). I don't know where Amber stores the processed image, but I bet my *** it is a major culprit candidate.
 

da9000

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Re: Corrup A3000 interlaced display on LCD monitor

There are some extra (fast) RAM chips near amber (4 of them I think) that store the non-interlaced frames. They get hot.

Unfortunately I don't have any ideas of why the OP's screen looks like this, but he's right: the flickerfixing happens inside the Amiga and shouldn't matter to the LCD. HOWEVER, because there might be slight timing differences I'd follow TheCorftiot's suggestion but only after you (the OP) try the little potentiometer in the back of the A3000 (there's a tiny whole next to the output connectors). Put a small flat headed screw driver in there and play around with it. It'll modify the timings and could possibly solve your problem.

Cheers
 

TheCorfiot

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Re: Corrup A3000 interlaced display on LCD monitor

Having viewed the piccy

This is defnitely a timing issue NOT RAM corrupting the data, If you had a faulty RAM Buffer then you would get screen corruption or at worst missing alternate scanlines.

The piccy is identical to my A2000's Microway flicker fixer when you try to drive it at NTSC resolutions ie 60Hz but with a 50Hz PSU generated Tick signal.

TC :mrgreen:
 

SJBUK

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Re: Corrup A3000 interlaced display on LCD monitor

Well, jumpers seem OK as far as I can tell - J350 is 1-2, which I believe is corect for Tick source .

I tried tried changing PAL/NTSC jumper to 1-2 (NTSC) and it booted into 640x200. Tried interlaced modes and got the same problem.

On a side note I noticed similar corruption when booting off an old cover disk and firing up Superfrog. The logo screen was corrupt although the game itself seems OK.

All other jumpers seem OK, though the jumper settings I've seen documented don't quite seem to tie up with the Rev 7.3 board I've got.

For the curious my jumper settings are:

J100 1-2
J102 2-3
J103 3-4
J104 1-2
J151 1-2
J152 1-2
J180 1-2
J181 1-2
J200 2-3 (tried 1-2 which gave me NTSC)
J350 1-2
J351 2-3
J352 2-3
J481 2-3
J482 1-2
J483 Empty
J851 2-3
J852 1-2

Now to get the damn case back on, power switch keeps getting jammed :-(
 
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