Amiga 2000 rev 6.2

General hardware issues and troubleshooting etc

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terriblefire
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Re: Amiga 2000 rev 6.2

Post by terriblefire »

Kepler wrote: 06 Feb 2024 07:50 I have looked at the serial output and unfortunately it doesn't reveal anything other than "no chipmem detected".
I have since removed all 8 RAM ICs, soldered sockets and used 8 known working RAM ICs. However, that odd behavior on the HLT and RST lines has remained.
Hold down either left or right MB during boot. It will disable chipram test and let you get to the menu. Then do the chipram check. What does the OVL test right at the start say?
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"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
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Re: Amiga 2000 rev 6.2

Post by Kepler »

I have attached an image of the serial output.
I will try bypassing the chipmem test shortly.

Screenshot_20240206-084144~2.jpg
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stephen_usher
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Re: Amiga 2000 rev 6.2

Post by stephen_usher »

In which case it's something Gary is relying upon that's the problem.

Seeing as you're having memory detection problems and Gary has a lot to do with the memory control this would suggest the problem is somewhere in Gary's vicinity, maybe the socket.

For a start check pins 20 and 21 (RAM enable and ROM enable) to see what they're doing, both on the PCB and on the chip leg.
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Kepler
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Re: Amiga 2000 rev 6.2

Post by Kepler »

Gary pin 20 RAMEN is constantly high on startup.
Gary pin 21 ROMEN seems to change between being high on startup or momentarily high and then go low.
That behavior is the same from the IC and board.
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Re: Amiga 2000 rev 6.2

Post by terriblefire »

I don't think it's gary. looks like a ram issue. diagrom has checks for Gary
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
Kepler
Posts: 67
Joined: 05 Feb 2024 19:09

Re: Amiga 2000 rev 6.2

Post by Kepler »

I can't seem to bypass the chipmem test by holding the mouse button down. Of course, I don't actually have any proof that the mouse functionality is working on the machine. I know the keyboard functionality doesn't work. The caps light doesn't come on nor does the keyboard reset work.

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