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?

[Zac67]

Hmm, I was pretty sure that all square Agnuses 8372 and beyond can do both PAL and NTSC, according to the Test pin (pulled low: NTSC).
My A3k's got an 8372B (318069-03) which BBoA says should be an 8372AB PAL - and I've used it with both PAL and NTSC a lot (both soft- and hardware switched). I guess the info is not very complete...

Denise doesn't care whether NTSC or PAL at all, so that's not it. Probably the Megachip runs specific version only - any jumpers/solder bridges?

After upgrading my old A500 to 1 MB chip back in the golden days, I used a very thin piece of plastic foil to isolate pin 41 (?) to be able to run PAL (later I soldered a wire to the chip and bent the socket pin). Trace J102 to Agnus' socket to make sure it's the right pin. Then check the Megachip to see if it grounds this very pin.

[leofoe]

Xanxi wrote:
Anyone has a good tutorial about battery replacement?

http://amiga.serveftp.net/battery.html

[J-Golden]

IIRC, there are two dif. places to put the "connector" wire on the 68000.  Have you tried both paces?  I think it was to pull power so it might not do anything but then again, it would never hurt to try.

J-GOlden

[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?

[Zac67]

The differences are:
- number of scan lines
- vertical frequency
Running 200 scan lines (NTSC) with PAL frequency results in the 'cinemascope' border at the bottom. Note that these lines are scanned by Denise, but lacking display data they have background color. Software usually checks Vsync to check for NTSC/PAL.

Furthermore, PAL & NTSC Miggys own slightly different clock crystals (NTSC and PAL differ in horizontal frequency), but this only matters for additional video hardware (FF, genlocks, A2024).

Is it possible to open PAL screens when running this involuntary NTSC mode?

BTW: the additional wire is for transmitting the A20 line for addressing the 2nd MB. 68k pin 48 sounds pretty good, but maybe it's not connected on the '030 card in '030 mode. If you own a multimeter you should be able to measure 0 Ohms between the different connection points for the cable.

[motrucker]

My manual also says to use #s 318069-11 for NTSC & 318069-10 for PAL. Even though you have a 8375, it may be a version that won't work. I had a different # 8375 in my A2000/MegaChip 2000, and it would NOT work until I replaced it with the 318069-11 (I have an NTSC system), then it worked fine (has has for over five years now).

[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.

[Zac67]

I'm pretty sure the hardware selection pin is grounded. The Early Startup overrides that, so it works.

[magnetic]

hmm I'm confused by this thread (i'm a little slow) so what do I need to have the Megachip work in BOTH PAL and NTSC? Thanks

[save2600]

If you're playing games off WHDload, then you need TUDE or Degrader off aminet.net.

If you're just fooling around with most Workbench programs, then the early startup menu (hold down both mouse buttons) in Kickstart 3.1 should do the trick.

If you're playing games off original floppies, then NTSC/PAL switching will be done automatically and all you might have to do is adjust your monitor's vertical width to see the entire picture or to stretch it out.

[desantii]

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.
 

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]

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?