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missyrelm

Modding an Amiga CD32 to RGB

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Hi,

 

My wife and I are trying to find someone to mod an Amiga CD32 to output RGB and are looking for suggestions as to who can/will do it.

 

We am getting ready to buy an Amiga CD32, but our TV is NTSC, and only accepts 60hz signals. So, we are hoping to get around that by modding the CD32 to output RGB instead.

 

Our Samsung TV’s specs say RGB input, and on the back it says “PC input”, which I am assuming is the RGB.

 

My understanding is that as far as mods go, this is a pretty easy one, I just don’t know how to solder or read schematics, and don’t want to practice on a classic console.

 

We have a good history of buying modded consoles and mods of consoles that I provide…

I can provide a list of people I’ve done business with, and also we have an excellent rating on ebay as buyers.

 

My understanding is that the mod is “just” taking an amiga rgb cable, cutting the db 23, then locate the RGB and video at the TP9 test port near the fmv connector,

where there are pins where you can solder the cable.

 

Thanks to anyone who can help!

 

Here is the schematics from the Amiga CD32 FAQ

 

http://www.faqs.org/faqs/amiga/CD32-FAQ/part2/

 

CD32 RGB signals...

 

The RGB signals are available from a test port, TP9...

 

| | | <--- Kickstart ROM .-. Desc Equiv pin #s

| | | |o|

| | | |o|

| `--' .----. <--- Akiko |o|

| | | |o| HSync 159

| | | : <--- TP9 |o| VSync 160

| `----' : |o| Red 163 and 164

| .. :o.--. |o| Green 165 and 166

`-------'`----------' | |o| Blue 167 and 168

^ ^ `------- |o| CSync 157

| | |o| Ground 161 and 162

Expansion port Pin 182 `-'

 

The RGB signals come from the D/A conversion unit and lead directly

to the expansion port. These signals are, however, not amplified. In

addition they are weakened by the S-Video output unit.

 

As a result I (aim to) insert a 47 Ohm resistor to each colour signal

connection. You may also reduce the load by interrupting the signal

supply to the S-Video unit. Set pin 174 of the expansion port to GND

to achieve that (174 --> u36 (4066) signal switches).

 

The sync signals connected to the expansion port are unbuffered. As

a result you may re-synchronize your Amiga by an external tact

source. You schould at least buffer the CSync line; there is no

external synchronisation possible on this pin.

 

Hint: make use of an XOR gate chip. You may negate certain sync

line(s) to adapt your Amiga to (old? :-( ) multiscan-monitors (the

A4000 monitor adapter box will do the same; without the possibility

of selected negation).

 

Written by Klaus Hegemann, posted as part of 'CD32 expansion port

info' by Anders Stenkvist in comp.sys.amiga.hardware, forwarded by

Michael King.

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The CD32 outputs 15Khz RGB, so it's in almost a certainty that your TV will not sync that low. You need scan doublers to hook the old 15Khz RBG video machines (like the Amiga and ST) to modern monitors.

 

The good news is that the s-video out of the CD32 is very good. :)

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So you have an NTSC tv, but you are buying a PAL CD32? Weren't these made in NTSC versions as well? In which case, no mod required, either use the composite or S-Video. Am I missing something?

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So you have an NTSC tv, but you are buying a PAL CD32? Weren't these made in NTSC versions as well? In which case, no mod required, either use the composite or S-Video. Am I missing something?

Thanks for bringing up the question of whether or not this will work… Of course I don't want to do this if it won't work... :(

 

My understanding from researching this heavily is that

even when using a NTSC CD32, when it plays PAL games it will switch to the PAL signal after the starting screen, and that it will output 50hz with both composite and S-video, but that RGB would work on any TV that allows for RGB input.

I got this from many sources, including the following

 

 

Unless I am misinterpreting it, the Amiga FAQ at

http://www.faqs.org/faqs/amiga/CD32-FAQ/part1/

says that the only way to avoid the 50/60hz problem even when using the “mouse NTSC/PAL changing trick” is to either use a TV that takes both 50 and 50hz or to mod a CD32 to output RGB…

 

Am I misunderstanding this?

 

Here’s the quote:

 

“TVs/monitors connected to the CD32 through the French CD32's or SX-1's

or CD32x's or TP9's (see diagram at end of FAQ) RGB connector will also

work fine.

 

TVs/monitors connected to the CD32 through the composite or S-Video

outputs won't work though. The problem is that the PAL colour signal is

still sent at the NTSC frequency.”

 

My understanding is that using a NTSC CD32 will not fix this when playing PAL games,

Here is a quote on the subject:

 

Here is a quote from Akira on the English Amiga Board some years ago..

http://eab.abime.net/showthread.php?t=1761...t=cd32+ntsc+pal

“It goes well beyond that, some games will just not run when facing NTSC timing. It's not a matter of having your TV displaying PAL as well...

 

Besides, NTSC CD32s display 50Hz NTSC instead of real 50Hz PAL when playing in a "PAL mode". The color system is STIL NTSC. So you need a TV that supports 50Hz NTSC (not all of them do, I even had problems with professional projectors in demoparties)

 

I know, I have an NTSC A1200 and it's quite a bit incompatile with loads of shit.

 

I wouldn't purchase an NTSC CD32. It's not much extra money to get one from Europe. Let's keep in mind then you will need a TV that displays PAL or to conect the CD32 through RGB (needs modding)”.

Edited by missyrelm

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I think I understand what your issue is - but I'll repeat - even if your TV takes RGB it is almost 100% not going to display the RGB output from a CD32/Amiga/ST.

 

The reason it is so easy in the UK for instance is that SCART TVs will display 15Khz RGB natively. Nearly every monitor and TV here in the US unless they are very old is not going to display 15Khz RGB video without a scan doubling device.

 

I know, I have an NTSC A1200 and it's quite a bit incompatile with loads of shit.

That is true, however if you're 1200 is expanded, has a hard drive, and you use WHDload you can load huge amounts of software directly from the hard drive and the incompatibility issues are automagically fixed. I love WHDload and use it both on my 1200 and my CD32 SX32Mk2. :cool:

Edited by remowilliams

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Bad news for me :( Well its better to find out now than after buying one, but its very dissapointing...

 

Thanks for the help, you probably just saved me loads of money by explaining that...

 

I think I understand what your issue is - but I'll repeat - even if your TV takes RGB it is almost 100% not going to display the RGB output from a CD32/Amiga/ST.

 

The reason it is so easy in the UK for instance is that SCART TVs will display 15Khz RGB natively. Nearly every monitor and TV here in the US unless they are very old is not going to display 15Khz RGB video without a scan doubling device.

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There's another problem here that should be mentioned... If you buy a PAL CD32, then not only do you have to have a TV/monitor that can handle 50Hz, but it also has to be able to handle a PAL color signal! Even if your TV can do one, there's no guarantee it can do the other, and North American TV's will almost never mention whether they can do these things or not.

 

Everyone who has a CD32 will happily tell you that you can switch it between PAL and NTSC mode, but many of them do not realize that all this does is switch between 50Hz/60Hz output. A PAL CD32 will ALWAYS output a PAL colour signal, and an NTSC CD32 will ALWAYS output an NTSC colour signal. Aside from serious hardware modification, there's no way to change this.

 

!Long Story Warning!

 

Back when I first decided to get into CD32 stuff (having been a long-time Amiga fan), I figured I'd get a PAL CD32, since 99% of the games are PAL. I was told that it would work fine on a Commodore 1084S monitor as long as I hooked it up in S-Video (The 1084S doesn't actually have an S-Video jack on the back, but the seperated Luma/Chroma jacks are the same signals, so close enough). When I hooked it up, all I got was black and white. The picture was nice and stable, since the 1084S handles 50Hz properly, but having no colour is a real problem. Neither composite nor S-Video would give me colour.

 

Luckily, I knew that cheap PAL-to-NTSC converters existed... now, converting 50Hz to 60Hz is no small task, and REAL PAL-to-NTSC converters are damned expensive, so all these cheap ones do is convert the color signal and leave the video at 50Hz. That was plenty good enough for my case though, so I picked one up off eBay. However, the thing is total garbage, and the picture is just awful. Color was alright, but everything was so blurry that I preferred just black and white! Plus, the adapter had it's own AC adapter, which is always a nuisance.

 

At this point, I broke down and bought an NTSC CD32 from China. It works great on my 1084S, and I've only found a handful of games that won't work on it (I have about 85 games, and I can only remember one off-hand that didn't work: F17 Challenge).

 

The moral of the story is that you should avoid PAL CD32's unless you're absolutely sure your display can handle all aspects of a PAL video signal. I've heard that if you modify a CD32 for RGB output, then you can avoid the PAL/NTSC colour signal issues entirely, though I can't confirm this myself. I've considered doing this mod to my PAL CD32, but I haven't had time to go about it.

 

--Zero

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I've heard that if you modify a CD32 for RGB output, then you can avoid the PAL/NTSC colour signal issues entirely, though I can't confirm this myself. I've considered doing this mod to my PAL CD32, but I haven't had time to go about it.

Here's some pics of my CD32 with the SX32Mk2 installed, and a few pics of the upgrade itself.

 

post-5887-1206843837_thumb.jpg post-5887-1206843846_thumb.jpg post-5887-1206843852_thumb.jpg

 

A pic booted into Workbench 3.1

 

post-5887-1206843856_thumb.jpg

 

RGB out is 15Khz, and no it unfortunately does not solve the problem with issue games such as Nick Faldo's golf as you can see.

 

post-5887-1206843869_thumb.jpg

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RGB out is 15Khz, and no it unfortunately does not solve the problem with issue games such as Nick Faldo's golf as you can see.

 

post-5887-1206843869_thumb.jpg

Are you playing the game in PAL mode or NTSC? Switching into PAL should fix that problem.

 

--Zero

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Are you playing the game in PAL mode or NTSC? Switching into PAL should fix that problem.

You mean the two mouse button pre-boot screen? Going PAL/NTSC doesn't seem to make a difference.

Edited by remowilliams

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Strange... I've played lots of games where the screen was clipped in NTSC like that, but they worked fine when I switched into PAL mode (Fire & Ice, Benefactor, The Big 6, etc), though I don't own Nick Faldo's Golf, so I can't test that one. What kind of monitor are you using? Your screenshot looks like a 1084S, which is exactly what I'm using too.

 

--Zero

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