DCE Mini-Megi Chip installation

[x56h34]

I recently bought this chip from Vesalia. It's a revision 2.1 Mini-Megi Chip with an NTSC 2MB Agnus soldered onto it. I've installed it in my revision 6.2 NTSC A2000.
The instructions were in German, however I think I figured out how to install it, but...

Although the A2000 now reports 2MB of chip ram, I notice that all of a sudden, there are some graphics glitches when I navigate through OS3.1 or OS3.9. Menus would look corrupted, as well as icons. There are no crashes whatsoever, but graphics seem slightly trashed.

This doesn't happen with the original, 1MB Chip RAM setup, so I'm sure my A2000 itself is OK.
It does however happen regardless of whether I strip the A2000 down to just basic 2MB Chip ram, 68000 CPU, no hard drive, no SCSI, or leave all the expanded stuff in.

I was wondering if there is some extra configuration that I may be missing, like a jumper which needs to be switched, or similar?

Thanks for any help in advance.

[EdKing]

I noticed the same on my 2000 w/MegaChip2000/OS 3.1/3.5. Just minor little glitches, more annoying than anything else. I don't get them with OS 2.0, so I figured it was something with 3.x.

BTW, did you ever get your catweasel to work w/WHDLoad ?

Ed King

[x56h34]

Ed, I appreciate your continuous effort in helping out with my problems.
It's good to know that Mini-Megi chip by design will give those glitches, with 3.1 rom. I don't really want to switch to 2.x rom from 3.1, so I guess I'll have to take it as it is. :-)

As for the WHDload issue, I haven't yet tried to fiddle around with it. I may leave it as it is, and strictly use my A1200 for WHDLoad gaming, and leave the A4000 highly expanded. :-) The Catweasel/Buddha S-class card is just too cool. ;-)

Thanks again.

[EdKing]

x56h34 wrote:
Ed, I appreciate your continuous effort in helping out with my problems.

No problem, I got a lot of help from here getting my Amiga on my home network, just trying to return the favor.

It's good to know that Mini-Megi chip by design will give those glitches, with 3.1 rom. I don't really want to switch to 2.x rom from 3.1, so I guess I'll have to take it as it is. :-)

That's the way I felt about it, I hardly notice the glitches any more.

Ed King

[x56h34]

Ed, your chip is a DKB product, right? Could it be that both DCE and DKB couldn't figure out a way around the 3.1 rom glitches? :-? Or was it that the boards were designed before 3.1 rom was released?

[EzdineG]

@x

This may be way off the mark, but... When you stripped your 2000 to nothing, did it have a fresh OS install?  I have a Megachip, Topchip and Elise and none of them exhibit corruption on my r6.2 2000.  They do, however, have graphics corruption when picasso96 libraries linger in the LIBS: folder with no use of a p96 monitor driver.  It is especially noticeable with the icons.

LMK, maybe I can assist further...
Adrian

[x56h34]

@EzdineG:

Yeah, these glitches happen no matter what, even when my A2000 is with only these specs:
68000CPU, 3.1Rom, 2MB chip ram, and nothing else.
I would insert the WB3.1 floppy, let it load up, start opening windows, moving them, resizing, opening menus, and the glitches would still be there.

Keep in mind that you most likely have a different product (DKB MegaChip) and I have a DCE MiniMegi Chip. They sound similar, however they are a totally different design by 2 different companies.

Interestingly enough, the Picasso96 libs glitches when no driver loaded look about exactly the same as this problem of mine. I know, as I've used P96 with other Amigas, and before I would activate the actual monitor driver, the regular native screen within the OS would always be glitchy.

[Lemonty]

You mentioned the jumpers and the manual mentions them.
Firstly, J101 needs to be shifted from the standard right position to the left (towards the powersupply cables).
Secondly, jumpers 500 and 102 need to be seperated with a knife. The jumpers are square welled points or something and should be cut seperate. Hope this helps and ask a German speaking Amigan to be sure - I am Dutch, which is close but not close enough (thank Goodness).

[x56h34]

Thanks Lemonty.
I'll look into it this weekend. I think that this concerns only the old A2000 models with the 512KB Agnus chips. The ECS A2000 units (like mine) should already have this set by default, however it doesn't hurt to check.

[EzdineG]

Sucks the Agnus is soldered in, because that was my next guess.  LMK

[EdKing]

x56h34 wrote:
Ed, your chip is a DKB product, right? Could it be that both DCE and DKB couldn't figure out a way around the 3.1 rom glitches? :-? Or was it that the boards were designed before 3.1 rom was released?

I got my MegaChip around the time 2.04 was the latest, and the 3000's were just hitting the market. I tried 2 different 3.x roms, 2 revs of the original Picasso software, as well as with Picasso 96. I still got the glitches without the software or Picasso II card installed. I even tried all the different color depths, from 2 to 16 million.The glitches are not present when I switch to 2.x roms and OS, so I just figured it was something to do with 3.x, and have learned to live with it.

Ed King
 
P.S. I just read on the Big Book site that theMiniMeg can run hot and may need extra cooling. I didn't know if you heard of this so I thought I'd let you know.