A3000 help please

[graffias79]

Hi.  I have a problem with an A3000D machine here.  It's running KS & WB 2.04. I think something may be wrong with Denise.  I get some violent video corruption.  I've seen it happen on the workbench which is 640x200 2-Bit, DPaint 640x200 3-bit mode, and some very nasty corruption in HAM mode.  My question was can the A3000 use an OCS Denise or will the A3000 ROM gag on it?  I have an old half-dead A2000 here that I could turn into a parts mule for other Amigas.  Maybe Denise is not at fault at all now that I think about it, could it be a chipram issue?  I guess another question is did the A3000 ever come with only 1MB of chipram?  (mine is an A3000UX / Superkickstart 2.04) (Yes I took the AMIX HDD out of the computer :-) )

Please and thank you for any insight!
-Jamie

Also thought I might add that I doubt it is a heat issue because it happens even when the computer has just been turned on (maybe 25 seconds to boot and another 10-15 to load DPaint)

[graffias79]

Hmm it looks weird like in DPaint when i have a stamp and i click to stamp it down (god i sound smart here lol) like the stamp is smeared horizontally as if the horizontal hold dial on an old tv has had it's influence on it.  and yes gadget corruption as well, icons come up sometimes as digital noise (if that makes sense) left or right sides of windows look like $hit in workbench.  it was worse during the os install.

I removed the battery when I got it, there was a small circle of destruction around one pole of the battery but it did not cover any of the traces just solid lighter green on the mb.

Other than that the cpu seems to run ok, everything else is alright, even the scandoubler circuitry seems to be fine

Thanks
-Jamie

[graffias79]

Also, yes, the Amiga 3000 did come as 1M CHIP.  My 030/25 came with 1M CHIP/1M FAST.  I swapped the 1M FAST to CHIP and replaced it with 8M FAST with the first paycheck after I bought the thing.

Oooh this one has 1MB chip and 8MB fast.  Please tell me how to make one more MB chip!  I'll be honest, I'm pretty new to the big box amigas  I cut my teeth on an A500 and A1200 :-)  My 500 I converted to 2MB chip with a fat agnus replacement board, and my 1200... aaah my beautiful 1200... :-)  I love that computer hehe.. oops anyway my 3000 is kinda plain jane.  All the goodies are in the 3000T.  I do have an emplant board in the 3000D but I am not a mac person at all so I want someone else to have it lol.  Unfortunately I do not have any install disks or anything for it.

-Jamie

[graffias79]

As for the video problem.
If it's a permanent thing, and you're using the scandoubler and SVGA port, then adjust the 20 turn trimp pot in the hole for minimum video distortion.  You might have to use a plastic or ceramic tuning tool.

If it's an intermittent problem, try pressing down on the socketed devices in the video section and see if the image alters.  It could be intermittent problems with IC sockets, or corrosion in the U450 (Denise) socket.  As it's right beside the RTC battery, it gets easily corroded.
If there is a socket problem, remove it and solder the device directly into the motherboard.  Those kind of IC sockets cause nothing but trouble.

Could also be a problem with the PAL logic devices as mentioned in one of the other posts, but it's best to replace them to check this.


And as far as I know, ECS Denise is pin compatible with the OCS one.

A3000s with a green drive LED were usually ECS and ones with the red LED were usually OCS.

Mine has a green LED but strangely the HDD LED never lights up.  The little PCB on which the LEDs exist does not look damaged or cracked either, just slightly flexed where it's screwed in.  Anyway off subject.  I don't think its the scandoubler at all since on DPaint, if the video corruption occurs on the screen it becomes part of the picture.  I can select and stamp the glitches as if I drew them myself which is what makes me suspect chipram.

I've taken her apart and reseated all the chips (paying special attention to denise) to no avail.  Where can I find some program assistance logic chips?  Are they a standard part or special for the Amiga?

I would still like to try my OCS Denise, but I don't want to cook anything!

Oh and if I remember right, Agnus was version 8372B.

Thanks
-Jamie

[graffias79]

Noster wrote:
Hi

@graffias79

Are you shure that your problem isn't the result of an amok-running program ?
Have you the same troubles if you boot ypour system using a floppy and start DPaint from floppy ?

Noster

Hello,

The corruption existed booting from the install disk for OS 2.04 as well, and DPaint is the only program I have installed on the machine so far.  not even a screen blanker or any commodities.

-Jamie

[graffias79]

Ok just for S&G I transplanted a standard OCS Denise chip into the A3000.  For all practical purposes it worked just fine, except no ECS modes (of course).  Unfortunately the machine is still flaky.  It seems to bring out the worst in HAM mode.  I checked the PAL chips, neither seemed very warm, the chipram is soldered on to the motherboard (theres an equal ammount of unpopulated dip sockets next to it I assume for 1 more MB of chipram).  I'm begining to suspect the power supply at this point. :-(  Oh well  Thanks for all the help anyway.