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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Xanxi on September 24, 2005, 01:50:55 PM
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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.
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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?
(http://img255.imageshack.us/img255/3034/a2000mobo5gc.jpg)
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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.
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Xanxi wrote:
Anyone has a good tutorial about battery replacement?
http://amiga.serveftp.net/battery.html
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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
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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.
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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?
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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.
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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).
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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.
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I'm pretty sure the hardware selection pin is grounded. The Early Startup overrides that, so it works.
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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
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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.
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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.
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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?
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When I installed my mega chip I always attached to the gary chip not the cpu
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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
I suppose only AGNUS "VBB" can switch PAL/NTSC...
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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
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?
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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?
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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. :(
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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 :-/
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When I did teh swap mine came from an A500+
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I will give it another try in some weeks then.
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Hi, be sure to have all "lastest" NTSC ECS chips rev.
And don't forget the "timer" jumper.
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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 :-/
Really strange. However, there have been reports that "A500+"s were produced with an older board rev and 1 Meg Agnus (just Kick 2.0 to justify the "+") - might this be one of those, ie. not capable of 2 Meg chipram? Otherwise I have absolutely no idea, sorry.
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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.
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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.
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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.
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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 :D 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 :)
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Hey guys fyi there is really nice like new DKB megachip NTSC 2mb for sale on ebay right now!
http://cgi.ebay.com/Amiga-DKB-MEGACHIP-2mb-Video-Ram-Upgrde-a500-a2000-CDTV-/320590304295?pt=LH_DefaultDomain_0&hash=item4aa4abd427
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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.
:-)
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I don't know if it helps but recently i installed a 8372 in my A2000 to replace the 8371 and suddenly my A2000 became NTSC.
I take it the Agnus was an NTSC version ?
Anyway there are some jumpers which i set and the A2000 became PAL again.
If you want i can see if i still have the guide i used.
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Cool. Bring them on. I have an NTSC(Never The Same Colour) Angus in my MegaChip2000. Seems to work okay on all the software I use. I do use an A2320 and a Picasso II Card though.
Apart from that there is one weird problem where my Memory (16MB on GVP 040 & 1 MB of chip) dissapears on some cold boots.
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Ok.. I followed this guide which was for upgrading the agnus and and changing some jumpers so that i can map a full 1mb of chipram.
http://www.nightfallcrew.com/30/09/2...ipram-upgrade/
I am 99% sure of this but for you the part of J102 is the only part you will need as it is the part which either forces the A2000 as PAL or NTSC. I forced mine to PAL and it worked perfectly. Do a google search to be sure, but in the end of the day you can always change it back if it doesn't work. Worked for me first time and perfectly.
I think it was a "jumper trace" which you have to cut with a blade and not an actual jumper. Like i said if it doesn't work you can always close it again with a small blob of solder, 30 second job. :-)