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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Vanfanel on July 13, 2011, 03:37:31 AM
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Upon doing some reading on the internet today, I discovered about how the American NTSC A1000's Denise chip can't do EHB modes. Opening up my case, I discovered that it is indeed the case with mine. That being said, what would you recommend as a replacement for it, considering its sole purpose is for gaming. Also, I already have an A1200, but have seem to have out of sync issues when older games use multiple audio channels, so I'm going for as compatible as possible.
Another thing I read was that the ECS should be fully compatible with OCS games, but that the A500+ couldn't run some games that an A500 could. Was the ECS at fault, or was that something else.
I suppose I could also just replace the Denise chip with one that does support EHB, but I'm still curious about this question. Thanks!
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Unfortunately theres no absolute answer here. OCS/ECS/AGA all have some imcompatibility issues with some software. Theres some old games that wont run on OCS machines too (elfmania and stardust for 2 random examles). An a1200 + fast ram +whdload is probably the best compromise in my opinion.
Slightly off topic, but:
@anyone who knows:
As for some a1ks not having ehb modes, whats the story in regards to dual playfield displays? Are they limited to 3bit + 2bit for playfields? (where does the 6th bitplane come from?)
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I haven't tried WHDLoad yet on the 1200. Once my subway arrives and I install it, file transferring won't be such a pain, so I can get the installs for the games I'm having problems with, and see if that fixes the sync problem.
I suppose, if I wanted max compatibility with the 1k, it would need to be another OCS machine with KS1.3.
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Side question. I just found a Denise chip (8362R8) on eBay (http://cgi.ebay.com/Commodore-AMIGA-8362-R8-DENISE-CBM-IC-Chip-252126-02-/250822303694?pt=LH_DefaultDomain_0&hash=item3a662c9fce). Would this work in my 1k?
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An a1200 + fast ram +whdload is probably the best compromise in my opinion.
Yep I agree, a 1200 makes the best (and most compatible) Amiga gaming platform. If you're having audio issues you might want to get that motherboards CAPS replaced + check for timing faults.
BTW file transfer will still be slow with the Subway, easiest solution is a CF PCMCIA card. I'm currently transfering loads of WHLOAD games and demos over to my Miggy from my PC using this method and it's quick and painless.
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Side question. I just found a Denise chip (8362R8) on eBay (http://cgi.ebay.com/Commodore-AMIGA-8362-R8-DENISE-CBM-IC-Chip-252126-02-/250822303694?pt=LH_DefaultDomain_0&hash=item3a662c9fce). Would this work in my 1k?
That's another OCS Denise, it'll work, but not gain you anything. You'll want an 8373R4 for ECS modes. It should just swap in to your A1000.
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It's only very, very old Denise chips (pre-OCS) that can't do EHB. My A500 has an OCS Denise (don't remember the exact part number but it's in the 836x range) and does EHB just fine. ECS Denise just adds the SuperHiRes and Multiscan (and Super72?) screenmodes.
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Yes, that chip will work and enable ehb. BUT, do you really need ehb??? If you ask around, you might find a spare ehb denise from someone who upgraded to the super (ecs) denise. I might even have a spare one burried deep...
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@anyone who knows:
As for some a1ks not having ehb modes, whats the story in regards to dual playfield displays? Are they limited to 3bit + 2bit for playfields? (where does the 6th bitplane come from?)
All chips have 6 bitplanes, you need them for HAM. However they only ever had 32 colours. With an extra bitplane that was only usable for HAM and dual playfield, someone had the idea of making colour 32-63 the same as 0-31 but half the brightness. I'd have added the extra colour registers, but they probably ran out of space.
That's another OCS Denise, it'll work, but not gain you anything. You'll want an 8373R4 for ECS modes. It should just swap in to your A1000.
I thought you needed the ECS blitter as well, which is slightly harder to fit in an a1000.
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OK, you guys could well be right. I wasn't aware that the A1000 chips are different to even the A500 OCS Denise.
I do know that you can upgrade an A500 or A2000 from OCS Denise to the ECS one for the extra screenmodes. I thought EHB was only in ECS, but I could well be wrong on that.
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@Andy. There is a monkey on your head!
Be careful.
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[nitpick]
Wouldn't a non-EHB-Denise actually be a Daphne ?
[\nitpick]
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As you're experiencing some problems with older games on your A1200 then you might want to look at a "Minimig v1.1". That way you get a machine with a real 68000 CPU (which can be cranked up to 50MHz in the menu for any flight simulators, etc), OCS and ECS chipset, and you can run either the ADFs or WHDLoad from a Hard File on the SD Card. You'll be able to get your whole collection of games on a 2 or 4GB card.
If you plan on using WHDLoad then get the 4MB version and not the 2MB one.
When MikeJ's FPGA Arcades appear in numbers then don't be surprised to see Minimig v1.1 machines appearing on eBay.
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Feature-wise it was Daphne without EHB, but I believe it was Denise when they rolled it out...
Some of the earliest Amiga 1000's shipped in the U.S. had the non-EHB Denise.
You should be able to swap it with no problem, according to this thread:
http://eab.abime.net/showthread.php?p=413514
I can confirm that I did have an ntsc A1000 with the non-halfbright denise chip. I dont know how early it was because I got it used. All I did was swap out the denise for a newer one and halfbright worked.
EHB was available in OCS, it wasn't an ECS feature...
There are very few games that actually use it from what I can see-online.
desiv
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Both the A1000 I now use, and the unit I just sold will/would handle EHB. I remember reading that this problem was only with very early A1000 units.
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Right, my 1k is one of the first ones, original owner of it since it was bought in 1985 (well, it was my parents then, but you get the idea). It does have the 8362R5 Denise. Upgrading it to a full ECS machine is beyond my capabilities since the chips aren't a socket for socket match. At least I now know I can replace it easily with an R6 or R8 for full OCS functionality.
Also, I should mention the sound sync problems on my 1200 I do not have on my 1k. As expected, it runs perfectly. I was hoping to go down to using just one, but I'll use both if I need to. I had a thought that perhaps the accelerator in my 1200 (DKB Cobra 030/33 32MB w/FPU) was screwing up the sound sync, so I suppose I could go through the trouble of ripping it out and seeing what happens.
Darrin: While I think the Minimig is a great concept, it's just not the same to me unless it's original hardware. Maybe I'm strange, who knows? But thanks for the suggestion!
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chip can't do EHB modes. Opening up my case, I discovered that it is indeed the case with mine. That being said, what would you recommend as a replacement for it, considering its sole purpose is for gaming.
Did you run into a game that actually used EHB?
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Did you run into a game that actually used EHB?
There are quite a few out there, from my understanding, though I don't have any in my possession as of yet.
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Upgrading it to a full ECS machine is beyond my capabilities since the chips aren't a socket for socket match. At least I now know I can replace it easily with an R6 or R8 for full OCS functionality.
I'd be surprised if you can't just drop in an ECS 8373R4 'Super Denise'. That should (in theory) give you the extra screenmodes. It certainly works like that in the A2000. Then again, a later-revision 8363 should be easier to track down (I know I have a few lying about the place) :)
The Agnus is a separate problem, since the A1000 Agnus is the "thin" 48-pin DIP version. I don't believe there is any upgrade path for those.
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There are quite a few out there, from my understanding, though I don't have any in my possession as of yet.
I'm not so sure... In quick searches, I don't see much.
Black Crypt apparently does, as it says so on the box.
Beyond that, I've seen some guesses, but no real info...
Mostly things like this:
http://www.atariage.com/forums/topic/85540-amiga-dedicaded-to-ehb/
It might not be as widely used as we think..
desiv
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@Andy. There is a monkey on your head!
Be careful.
No there isn't. I'm sitting on the head of a human. ;)
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Drop me a PM. I can send an 8362 Denise out your way
Right, my 1k is one of the first ones, original owner of it since it was bought in 1985 (well, it was my parents then, but you get the idea). It does have the 8362R5 Denise. Upgrading it to a full ECS machine is beyond my capabilities since the chips aren't a socket for socket match. At least I now know I can replace it easily with an R6 or R8 for full OCS functionality.
Also, I should mention the sound sync problems on my 1200 I do not have on my 1k. As expected, it runs perfectly. I was hoping to go down to using just one, but I'll use both if I need to. I had a thought that perhaps the accelerator in my 1200 (DKB Cobra 030/33 32MB w/FPU) was screwing up the sound sync, so I suppose I could go through the trouble of ripping it out and seeing what happens.
Darrin: While I think the Minimig is a great concept, it's just not the same to me unless it's original hardware. Maybe I'm strange, who knows? But thanks for the suggestion!
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Hi,
There was a chip replacement brought out for that a long time ago, I had one done to my A1000. If you can find one of those chips, the mod isn't that hard to install. Otherwise I would use Cloanto's Amiga Forever, it sort of automatically adjusts to any thing that you want to run. I think it is a great program if all you want to do is play old Amiga games, and it is cheap, it is 10 times faster and more compatible than a real Amiga, no choosing ntsc or pal, no choosing memory options, no choosing degrader options, it just simply works.
BUT
Do yourself a favor before you buy Cloanto's Amiga Forever, get yourself a modern day PC, I use a Quad Core PC, with up to date graphics cards made by AMD, it runs Amiga Forever and C64 emulators great. Don't try running it with an old 486 or Pentium type computers, you will be disappointed, my saying is "if it doesn't play the new PC games it just isn't good enough"
Thanks for listening, and no I wouldn't say Amiga Hardware isn't good enough because sitting right next to my Hexcore is my Amiga 4000 and Amiga 1200. Still use em, and still amazed at what they can do.
smerf
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Smerf: I already have a copy of Amiga Forever, and that's what I used to get my Amiga fix before I got back into Amiga hardware. And my PC is plenty to run it. :)
A note on the sound sync troubles I was having on the 1200, it was the accelerator. Took it out and the sound in the game was synced perfectly. At the moment, I can't afford to replace the accelerator (especially since I'm the kind of guy that would want to get the best possible thing), but I'll definitely make sure it can be disabled on boot. Gonna see if a WHDLoad install fixes the problem with the accelerator installed, but I doubt it will.
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Darrin: While I think the Minimig is a great concept, it's just not the same to me unless it's original hardware. Maybe I'm strange, who knows? But thanks for the suggestion!
Don't worry, I understand. I have an A2000 and A4000 running too along with my Minimig, FPGA Arade and Chameleon64 (not to mention the otehr Amigas gathering dust). :)
It is just a very handy machine for anyone who just wants to play games and considering that I managed to fit my board into a PS2 keyboard, it makes it a very portable Amiga gaming solution too (wrap the mouse and koystick cables around teh keyboard, put the PSU in your pocket and take it around your mate's house for a few hours of Sensible Soccer or Kickoff 2). ;)