DKB Megachip on A2000: PAL/NTSC issue, help needed

[Xanxi]

Hello.

I have an A2000 Rev6 PAL with a 8372A Agnus. I have bought on ebay a DKB Megachip but unfortunately, the Agnus fitted on it is NTSC only according to the Big Book (number 8375 318069-11). So before to try and fit it the 2000, i bought a PAL Super Agnus 2 MB in order to change the chip on the DKB: it is a 8375RO 390544-01 from an A500Plus.

But, with the DKB + Pal agnus my a2000 behave strangely: 2MB are recognized but it suffers several graphics glitches and eventually crashes completely.
With the DKB + NTSC Agnus, everything seems ok, even sysinfo says i have a PAL machine, but the picture is smaller, obviously NTSC. Maybe the combination NTSC Agnus + PAL Denise confuse sysinfo.

That's rather annoying to get a NTSC machine when it is supposed to be PAL. However, this A2000 used to have an RTG card to show workbench, and an Amber card flicker-fixer to output games. So, when it come to games and native amiga screen, what will happen with the sacndoubler?
How to make it PAL at last?
Any idea? Is it not possible to juste swap the agnus on the DKB?

thanks.

[Xanxi]

By the way, i have taken the opportunity of the A2000 open-heart surgery to remove definitively the battery that has leaked and damaged the mobo. The mobo still works just fine, despite its bad aspect.
See picture here:



Anyone has a good tutorial about battery replacement?

[Xanxi]

Unfortunately, i am not very skilled with electronics and i won't be able to trace signal or such serious work.
Currently i have connected a wire to pin 36 of Gary as required. There is an alternate connection possible with a pin of the 68000 i am going to try, but as this miggy has an accelerator 68030 board, i am not sure this will be effective in 68030 mode.
No jumper on the DKB Megachip. all i know is that Vesalia sell a PAL version and a NTSC version wich are not the same. I assumed the difference was only the Agnus version, but apparently not.

[Xanxi]

Mmmm apparently, it doesn't boot at all with wire to pin 48 of the 68000 (but it is rather difficult to make a good contact there).

The manuel says to use version 318069-10 for pal and 318069-11 for ntsc. My agnus pal is a younger version i think.


Sysinfo still says i am in PAL mode while i am in ntsc. What make the PALness of a miggy besides the Agnus?

[Xanxi]

Well it seems, it can run in PAL mode if i force PAL in the early startup of the 3.1 ROM.
Rather confusing.


Anyway, my best choice is to look for a 318069-10 and everything will be ok.

[Xanxi]

I have done that exact swap and it worked just fine so it might be an issue with your new Agnus or maybe the MB. The 8375 ones are hard coded to either PAL/NTSC so once you put the PAL chip it it will default to PAL (irregardless of your jumpers). You can then change in the early stratup or in workbench if required.

Well, that's what i call an old thread digging :-D

I am not using this A2000 anymore for now but i am planning to revamp it in a few months.
Would you have th exact reference of your 8375 Agnus for further upgrade (picture maybe)?
And can you confirm you have the DKB Megachip with clipped Agnus and not the Mini Megi with soldered Agnus?

[Xanxi]

I know I had apicture somewhere so I will look for it, it was the megachip with socketed 8375
 
swaped this one (from an NTSC megachip)
Agnus (2 MB) 8375 318069-11


To this one (to try to create a PAL megachip)
Agnus (2 MB) 8375 390544-01

I do not remember precisely, but according do what i wrote in this thread, i used a 8375RO 390544-01 from my A500 Plus with no success.

Is 8375RO so different from a 8375?
Where did your chip come from?

[Xanxi]

According to alexh's extensive studies, you have to stick with the '6-2' code as to which exact Agnus type you have/need. The four digit code + A/B/AB is not exact enough.

There are three different Agnus pinouts (A500/2000, A3000, A500+/600) and you'll have to get the exact type compatible with your chipram extender.

According to alex, 318069-11 is an A500+/600 type as is the 390544-01 - so if it doesn't work it's broken.

That's really peculiar because the A500 Plus Agnus that didn't work in the Megachip is working fine in the A500 Plus where it belongs :-/

[Xanxi]

I will give it another try in some weeks then.

[Xanxi]

Not strange at all.

As said before, even on this thread, the 8375 Agnus chips are hard-coded to either PAL or NTSC. Also, you can only swap a -11 type Agnus (NTSC) for a -10 Agnus (PAL). Another type of Agnus will not work at all as they have different pinouts. Period.

------------------

Now, for the battery leakage, drop some lemon juice or spirit vinegar over the affected area, let it over for a few minutes, absorb the moist and clean the area with IPA and cotton buds.

 If a trace is exposed, put some transparent nail varnish over it to protect the area.

So, i were right all those years Problem is i never found a -10 Agnus to replace my - 11.

Do not worry about the battery, this mobo has burnt one year after the initial post of this thread and has been replaced by a brand new

[Xanxi]

Hi.
I just wanted to say that, after seven years, i have finally swaped the Agnus chip on my DKB expansion to a 318069-10, and this time it is working perfectly as PAL, without any glitches.
I was right from the start.
:-)