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Rybags

Member Since 29 Sep 2005
ONLINE Last Active Today, 10:46 PM

#3117286 800xl Red Screen. I want to fix!

Posted by Rybags on Wed Nov 19, 2014 8:47 PM

Unsocketed board - makes it a whole bunch harder and more labour intensive.  Don't desolder or attempt to solder sockets in unless you have the required skills.

If you don't have the skill, practice on something not valuable like an old PC card that uses the large DIP chips or a game cartridge you can live without.




#3117265 800xl Red Screen. I want to fix!

Posted by Rybags on Wed Nov 19, 2014 8:31 PM

Powering up and the screen staying static colour means the OS can't initilize and plenty of things could cause it from failed CPU to bad Rom or Ram or a failed Antic.  Or it could be something as simple as one of the 7400 series logic chips that costs about a buck to replace.

 

An easy way to test if you don't have equipment like logic analyser is to swap in chips from the bad computer into a known good one at a time and see which ones don't work.

 

Main ones to test would be CPU, Antic, MMU, OS Rom, Ram chips.




#3116439 What was general opinion of Stargate 2600?

Posted by Rybags on Tue Nov 18, 2014 8:54 PM

Williams made the Defender and Stargate games, not Midway (which was later aquired by Williams).

 

Possibly the rights agreement wasn't struck by Atari and Williams which meant they used the Defender II title.




#3114431 In search of Basic B Cartridge

Posted by Rybags on Sun Nov 16, 2014 7:52 AM

Can't say I've ever had C behave badly.  Of course if you have programs that call routines within the Basic Rom itself then there might be potential for problems.

Also can't say I've ever heard anyone give negative response to C when comparing to the previous ones.




#3114420 In search of Basic B Cartridge

Posted by Rybags on Sun Nov 16, 2014 6:53 AM

In some ways B is the worst of the lot.  They fixed one move bug and introduced another.  The 16 byte bloat when saving is the least of it's problems.

 

Keeping a copy of A or B is worthwhile for collecting or testing purposes only.  If you have the means, then use C every time.




#3113606 If Atari made a new console, what would it be called?

Posted by Rybags on Fri Nov 14, 2014 9:46 PM

Atari Fukushima.

 

As in, the city with the nuclear plant which was swamped by the tsunami.




#3113524 RGB - a game for the ABBUC Software Contest 2014

Posted by Rybags on Fri Nov 14, 2014 7:04 PM

ESC aborts the game.

I'd rather see more levels than the burden of extra code to work out if you're at stalemate.  Besides that, you can still explore and maybe work out where it went wrong.




#3111836 What is the one thing you wished your Classic Computer had back in the day?

Posted by Rybags on Wed Nov 12, 2014 9:00 AM

First one was Atari 400 with only 16K and tape drive.

Obvious wants were more Ram and a disk drive (it already had one of the aftermarket "real" keyboards).




#3111080 Asteroids Emulator, When Did This Happen?

Posted by Rybags on Tue Nov 11, 2014 5:56 AM

There's options to increase the realism but in the end it's like doing pinball on a video screen - you can simulate it to a point but it'll never match the real thing.




#3110394 RGB - a game for the ABBUC Software Contest 2014

Posted by Rybags on Mon Nov 10, 2014 8:02 AM

Completed Easy, all levels in one go at last - score 444,600.




#3109235 Mac/65: How do I Change the Default Text and Screen Colors?

Posted by Rybags on Sat Nov 8, 2014 9:39 AM

Load into the emulator, you can find the addresses needing change within seconds.

It becomes a one-off thing but you could just as easily patch the executable.

 

I grabbed the disk based Mac/65 4.20 from http://www.umich.edu...mbly/m65v42.zip

 

Using change command within Mac/65 for background/text colours:

 

C 8B3F<82

C 8B44<0A




#3108483 The reason the Amiga failed.

Posted by Rybags on Fri Nov 7, 2014 12:35 AM

It failed for similar reason to the ST - didn't keep up with the competition.  They should have made 16-bit sound a priority and had it going when ECS came around in 1990.  Graphically, AGA should have been more full-featured - at the least a 16 bit colour mode rather than pissing about with the HAM mode and it's inflexibility.

Plus they persisted with the lower specced 68K series chips, realistically by 1992 the 68020 at 14 Mhz should have powered the entry-level machines and 68040 at speeds better than the 25 Mhz of the A4000, although it's worth remembering the 68000 at similar clock speeds had better throughput than probably any x86 up to the 80386SX.

 

You can apply the same to the ST/TT/Falcon and even the 68K Macs - and the common element again is the CPU.  It was almost as if Motorola lost interest in the 68000 by the time they started the joint PPC venture with Apple and IBM.  I don't think the 68060 ever saw light of day in a major consumer computer as an OEM component, sure it was available later as an addon by 3rd party manufacturers for Amiga and Falcon but by then it was too late and it was very much a niche/special interest type of purchase.




#3107011 US reticence.

Posted by Rybags on Wed Nov 5, 2014 3:07 AM

The BBC micro has a metal case to begin with, I don't know if the FCC would have had any influence on that choice.  The purpose of the machine was to be used in schools so they probably wanted a heavy-duty design.

Also, I don't think it came with RF modulator anyway so the situation there becomes more relaxed.

 

Probably the biggest problem the UK makers faced was that from 84 onwards the US makers had the price war going and they had absolutely no way to compete.  Their wholesale prices were probably higher than what the US retail prices were.




#3107003 Secrets of Speed

Posted by Rybags on Wed Nov 5, 2014 2:46 AM

You shouldn't need to do operations at the pixel level for shift + downscaling.  It's at the byte level, so either 4 or 8 pixels for most modes.

Unless you really need the extra colour, then a 1 bpp mode will make things a lot easier.  If you want stars and stuff behind then you could use PMG objects, throw a few DLIs in and suddenly you have dozens at little cost.




#3106985 US reticence.

Posted by Rybags on Wed Nov 5, 2014 1:52 AM

BBC was in no way price competitive with probably all the 6502 competition except Apple II.

 

The Sinclair machines - just face it, they're cheap entry-level machines and I don't think they were all that price competitive once they hit the US market.

A large part of Sinclair's success was patriotism in it's home market.  In Australia, they didn't make much of an impact.  In fact, the most successful UK maker over here was probably Amstrad in the mid/late 80s when most 8-bitters were starting to fade away.