Yet another Amiga 4000 hardware question.

[Countraven]

Hello Amiga fellows. The time has come to ask about your great help and support for one more time.

If you are boring to read all this the case is that the machine locks up on boot after a hard reboot attempt -power off and on-, it would get back to normal after ten or fifteen minutes.

So,

I have got back my Amiga 4000 today.

The motherboard is fixed, it got a damaged cia chip. Also some upgrades were made, PIO2 upgrade etc. So a new fixed mobo in town.

Everything was put together and back in action. My Cyberstorm PPC, with 128MB of RAM, my Picasso IV -Paloma TV card module included-, my Deneb USB card, a DVDRW and a hard disk, everything powered from a Liteon PSU. The on board RAM is 4MB chip and 16MB Fast Ram on five sticks, 4MB each. Those sticks were not the ones that my mobo used to have, but they were reported working on another 4000.

This configuration was working well in the past.

So, those are the symptoms that make me want to ask for advice.

The machine would boot fine. AmigaOS 3.9, AmigaOS 4.1 on all their victory. MorphoOS PowerUP was not booting, it used to with same configuration. Now this was a no go, actually the machine locked up when trying to boot in this partition, no drive clicks, however I am able to soft reset only to get on the same state. Anyway this is NOT the main problem but read above.

This is the important problem.

I discovered that the same symptoms would be presented when I switch off the machine and reboot. Let me explain. Amiga is off, I would power it on, it would boot and work fine. If I would turn tne machine off and power it on again after some minutes, it would lock up on the Deneb initial screen that appears on boot. Yes. I have tried without Deneb the machine simply locks up, anyway.

HDD light stays on.
No drive activity.
No booting.
There is caps lock on the keyboard and I am able to reset.

And sometimes a green screen on boot and then black screen, or as I said freezing on Deneb's intro screen. If I turn off the machine and turn on again for example on three or five minutes, it is still not booting.. But if I leave it off for a half an hour, or a quarter. It would boot normally.

So,

"Green screen means bad chip RAM", I thought. So I changed the RAM. Pulled out the five sticks of 16MB I was ussing and tried to boot with no RAM at all, thinking the the RAM on Cyberstorm will do the job. No booting. I tried with a single 8mb stick. Machine booted. I think I was using this 8MB stick initially on this Amiga.

Now the MorphOS is booting fine. So that kind explains that this should be a RAM problem. But the same prob remains. After second or third rebbot the nachine locks up on boot.

I have put the 8MB stick on the upper chip RAM socket.

The machine reboots perfectly on every soft reset from keyboard.

This PIO2 upgrade mainly improves hard disk speed, trying to test the hard disk behavior copying sn entire partition through AmigaOS 4.1, everything worked well, no crushes. Done that thinking that this upgrade could be the problem. It is actually a chip replacement on mobo.


Do you think is a memory issue?
Is there a way to bypass the on board RAM and use only the Cyberstorm RAM? Yes it is brand new.
Any further thoughts, ideas, advice?.

I will expect your replies.

 

[Astral]

Without reading all of the above again...the maximum chip RAM will be 2mb regardless of what is installed in that chip RAM socket.

 

[Countraven]

This is true. I keep on forgetting this limit but it eventually came into my mind

 

[Sir_Lucas]

You don't need the onboard 16MB Ram, you can take it out. You only need 2MB of Chip. CSPPC fast ram is good enough.

If I were in your shoes, I'd check the PSU as well.

 

[Countraven]

PSU eh? Good point. However this beast was serving the lady good all this time. It is the ideal one for 4000, but I will make a check.

ps. Yes currently she runs wearing one RAM stick - 8mb. I will try to find some more sticks to check out, always ONLY on the chip RAM slot.

 

[Countraven]

Original post, updated.

 

[radu14m]

did you recapped the mobo ?
could be a caps problem....

 

[Countraven]

Yes the mobo was recapped.

 

[Sir_Lucas]

The Chip RAM socket has to be filled with either a 1 or 2 MB SIMM.

Check that as well.

 

[Countraven]

Thanks a lot for the replies.

Some updates.

Please note that at last, the 8mb sticks were the original I used to have. So very close to the original config, minus the pio2 upgrade.

I discovered this: http://eab.abime.net/showthread.php?t=64203, please see forth post, it totally describes my problem. Original source is Amibay.

However I checked the mobo and it has the fix.

I tried booting with a Workbench 1.3 floppy, managed to do six reboots and then the machine locked up again. This could be a random fact.

Took out Deneb and Picasso, booted on floppy with a 1084 on the machine, managed to do two or three reboots, then the lock up.

I was unable to check without the cyberstorm, I have not got another cpu card.

Will try to put the original chips back taking out this pio2 upgrade, please note, those pio2 chips are not getting hot.

I sm seriously thinking to put back the original chips, taking out the ones of the PIO2 upgrade...

They can be put out with a tool... Never did something similar... Is there any guide for such task on youtube?

I need to take an idea of the whole thing.

Or perhaps some photos...

 

[Countraven]

Problem solved after putting back the original chips, removing the ones of PIO2 upgrade.