*I have organised the information below into sections under various headings and sub-headings. By scrolling down the page, you should be able able to quickly locate the information that you need. You should read this entire page to gain an understanding of the RGB adapter, paying special attention to the "Jumper settings" & "Technical data" sections.

This page contains the following sections:

1. Jumper settings

2. Instructions for use of a complete unit for Amiga (and other machines)
      2.1 - 23 pin D-Sub notes
      2.2 - Display options
      2.3 - Tuning

3. Application of an adapter with & without connectors (Amiga & non-Amiga applications)
      3.1 - Video synchronisation
      3.2 - CSYNC input
      3.3 - Output
      3.4 - Tuning

4. Technical data (dimensions of PCB etc)
      4.1 - PCB dimensions & cases
      4.2 - General
      4.3 - Components
      4.4 - Standards supported
      4.5 - Potential LCD TV issues

1. Jumper settings

You will notice that there are two jumper blocks on the RGB adapter PCB labelled "J1" and "J2".

J1 should only ever be on if you are using a CSYNC input. If you have a complete assembled unit plugged into your Amiga's video port, or you have wired up a HSYNC & VSYNC input, you will send +5v DC down the VSYNC line into your Amiga or other machine. Not a good idea! There is a warning on the PCB to remind you.

J1.

J2 is for grounding the other side of the trimming capacitor, so that you may tune the crystal part of the circuit if necessary (see 'Tuning' below). Leave J2 off to begin with, unless you are not happy with the picture quality. You should only need it if you are using the composite output - a.k.a. 'composhite'.

J2.

2. Instructions for use of a complete unit for Amiga (and other machines)

If you have purchased the complete unit for AUD$33 (to plug straight into the Amiga's video port) then this section is for you. You can also use a complete RGB adapter for non-Amiga applications, due to the 8-way plug on the PCB. Simply make a suitable adapter cable for your non-Amiga device and plug it into the PCB!

2.1 - 23 pin D-Sub notes

Due to the design of the 23 pin D-Sub connectors I have obtained, you need to remove the two nuts on either side of the Amiga's video port (a harmless procedure). If you don't do this, you won't be able to plug the adapter in! This is easy enough to do. You just need a tool small enough (such as needle nose pliers) to grasp the nuts to loosen them. Once loosened, they can easily be unscrewed with your fingers. I don't recommend unscrewing the nuts from the 23 pin D-Sub socket on the RGB adapter instead. They hold on the metal shroud, which provides some shielding, protects the plastic part from damage, as well as ensuring proper alignment of the two connectors - you don't want to damage those pins on the Amiga's video port!

Video port with nuts removed.

2.2 - Display options

First, chose how you want to connect the adapter to your viewing device - either composite (nooo, don't do it man!), or S-video (recommended). S-video gives a far superior quality of display than composite. I strongly recommend that you plug the cable into the adapter's composite or S-video socket before connecting the adapter to the Amiga's video port. You should grasp the PCB firmly by the edges only whilst connecting and disconnecting cables, or the adapter to/from the Amiga's video port. Since the adapter does not have a case, always take care when handling the adapter.

S-video and composite outputs.

2.3 - Tuning

Once everything is connected, you may need to "tune" the adapter slightly. This is especially true if you are using composite out. With S-video, it may not be necessary. I would have already tuned the adapter in the test phase after assembly, but it may require tweaking for your particular setup. Once you have an image on the screen, preferably with multiple colours, you may notice the image undulating or shifting in places, or perhaps the whole screen (basically, if the picture is not right, you need to tune it). If this is the case, you need to tune the adapter. For this you need a tiny 1mm wide flat bladed jeweler's screwdriver. Locate the trimming capacitor - it's the little metal component above the AD724 I.C./chip. Place the tip of the screwdriver carefully onto the trimming capacitor, using only enough force to rotate the plate and no more. Slowly, and in tiny movements, rotate the plate until the image is stable and to your satisfaction. Oh, and keep your eyes on the screen whilst doing so.

Trimming capacitor.

3. Application of an adapter with & without connectors (Amiga & non-Amiga applications)

Wire up your 8-way socket (female) and input cable according to the pins labelled on the "Video Input" plug (male) on the PCB. There is an explanation on the back of the PCB for ease of reference.

Video input plug. Rear of PCB.

3.1 - Video synchronisation

Video synchronisation signals can be provided by horizontal SYNC (HSYNC) & vertical SYNC (VSYNC) inputs, if your device outputs both. Make sure J1 is OFF if using HSYNC & VSYNC inputs, or you will send +5v DC down the VSYNC line into your machine! A complete unit for Amiga (with 23 pin D-Sub installed) uses HSYNC & VSYNC, so make sure J1 is OFF! If your machine only has a composite SYNC (CSYNC) output, see point 3.2 below.

3.2 - CSYNC input

If your device only has a composite SYNC output (or CSYNC), then do not fear! Simply put the jumper on jumper block J1, and make sure that the CSYNC wire is mated/connected with the "C" pin on the "Video Input" plug.

3.3 - Output

If you will be enclosing the RGB adapter in a case, you can wire up panel mount type RCA and S-video sockets very easily to the PCB, even with PCB mount sockets already soldered in place! The holes that you need to solder the wires to are adjacent to their respective connectors and are clearly marked, with an explanation on the rear of the PCB for ease of reference.

Video output holes for wires. Rear of PCB.

3.4 - Tuning

You may also need to "tune" the adapter after your hackery, and everything is connected, as per the instructions is section 2.3

4. Technical data (dimensions of PCB etc)

4.1 - PCB dimensions & cases

For those that wish to place their adapter PCB in some kind of enclosure, whether a dedicated case (or shared), the PCB dimensions (approx) and space needed are as follows: 50mm (W) x 80mm (L) x 18mm (H) - PCB with no connectors. With all connectors, the length (L) is approx 90-95mm.

Please note: The reason I am not offering the RGB adapter in a case at this stage is due to the amount of labour required, and also the extra cost incurred (by you) for the case, and other parts required. If I can work out a system and find the right tools so that I may do it quickly and easily, this may change.

4.2 - General

The heart of the RGB to PAL/NTSC adapter is the AD724 encoder IC, made by Analog Devices. It takes a standard analogue RGB signal, and converts it into a PAL or NTSC signal, so that an image can be displayed on a standard television set (LCD, CRT or plasma). It outputs the signal in composite, and S-video. Both outputs can be connected simultaneously, if you wish.

The IC requires a nice clean low-noise, +5v DC power supply to operate reliably. You may need to use a voltage regulator if your device outputs more than +5v DC.

4.3 - Components

The PCB has two crystals on board to generate the required PAL or NTSC frequency. Selection of PAL or NTSC output is achieved by simply moving the mini slide switch left or right. As indicated on the PCB - left for NTSC, or right for PAL operation. Slight adjustment of the trimmer capacitor may be needed for optimum quality of display.

Due to the fact that surface mount components are used, flexing of the PCB should be avoided to prevent damage to the components.

4.4 - Standards supported

According to the AD724 data sheet, the AD724 supports most of the common PAL and NTSC variants. However some aren't supported, and I will quote the data sheet directly: "There are, however, two known specific standards not supported. These are NTSC 4.43 and M-PAL. Basically these two standards use most of the features of the standard that their names imply, but use the subcarrier that is equal to, or approximately equal to, the frequency of the other standard. Because of the automatic programming of the filters in the chrominance path and other timing considerations, it is not possible to support these standards." So if you live in a region that uses those standards, you may have problems. Unless of course your TV can display true/regular (i.e. common types) PAL or NTSC, as many can these days.

4.5 - Potential LCD TV issues

Some LCD TVs don't seem to be able to display low resolution, non-interlaced signals, as outputted from some older devices like the Amiga (I believe that this is the problem, although I am not certain). This has nothing to do with a fault of the adapter, or the old hardware per se. So if possible, it's prudent to try out an LCD TV on your application before purchase (if you don't already own it that is). If it works with the composite out provided by the Amiga (or whatever), then it will work with the V2.0 RGB adapter. I spent about AUD$150 on a second hand LCD TV for my Amiga, before finding out it is great for everything but my Amiga, which is what I bought it for :-( It did work when I switched the output to interlaced through WB, but that is useless for games etc - so there is a clue there as to the problem methinks. Anyhow, the point is, not all LCD TVs will work - you have been warned!