*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 "DIP switch settings" & "Technical data" sections.

This page contains the following sections:

1. DIP switch settings

2. Instructions for use of a complete unit for Amiga (and other machines)
      2.1 - Display options
      2.2 - 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. DIP switch settings

All settings are made via the use of the bank of six DIP switches.

*NOTE: DIP switch number 6 should ONLY ever be set to 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!

NTSC output - Set DIP switches 1 and 4 to ON to set the RGB adapter to output an NTSC signal.

PAL output - Set DIP switches 2 and 5 to ON to set the RGB adapter to output a PAL signal.

Tuning - Set DIP switch 3 to ON to enable tuning via the trimming capacitor if necessary.

DIP switch bank. Rear of PCB.

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

If you have purchased the complete unit for AUD$35 (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 header on the PCB. Simply make a suitable adapter cable for your non-Amiga device and plug it into the PCB!

2.1 - 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 (you can use both the composite and S-Video outputs simultaneously if you wish - that is, you can use two displays at the same time). 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 may not have a case, always take care when handling the adapter.

2.2 - Tuning

Once everything is connected, you may need to "tune" the adapter slightly (you need to use a 2mm phillips head jeweler's screwdriver). 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 Phillips head screwdriver. Locate the trimming capacitor - it's the little component between the AD724 I.C./chip and DIP switch bank. 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" header (male) on the PCB. There is an explanation on the back of the PCB for ease of reference. Unfortunately, I didn't know the red paint would be so dull, so it is a little hard to read. Future batches will have white paint!

Video input header. 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 DIP switch 6 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 DIP switch 6 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 set DIP switch 6 to ON, and make sure that the CSYNC wire is mated/connected with the "C" pin on the "Video Input" header.

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. The holes that you need to solder the wires to are clearly marked.

The polarity of the composite holes are marked + (center pin) and - (GND).

The S-Video holes are:
1 and 2 - GND
3 - LUMA
4 - CRMA

Video output holes for wires ( for panel mount sockets).

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: 44mm (W) x 61mm (L) x 18mm (H) - PCB with no connectors.

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. There is a voltage regulator onboard the adapter PCB, which can take any DC input from 7-35V, and outputs the required 5V DC. However I recommend an input range of 9-12V DC. The filter capacitor is rated at 25V, so this should not be exceeded.

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 setting the DIP switches to the correct positions as explained previously. 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!