PAL Coco Differences

WELCOME
Looking for CoCo help? If you are trying to do something with your old Color Computer, read this quick reference. Want to contribute to this wiki? Be sure to read this first. This CoCo wiki project was started on October 29, 2004. --OS-9 Al

See Recent Changes. | About this site. | Join the E-Mail List or Facebook Group. | Contact me with updates/questions.

This page was last updated on 10/1/2024. Total Pages: 744. Total Files: 994.

---

Home / Articles - PAL Coco Differences

---

A guide to the various PAL Coco systems

Some other things just came to my mind (which is a little bit rusty after all these years):

I own PAL CoCos (and MC-10s) from different areas and they are all slightly different.

Germany, Belgium and the Netherlands

AFAIR, there's one group which has been sold in Germany, Belgium & the Netherlands (CoCo 1 to 2B). These are following the PAL-G standard and have a modulated RF video out on UHF (0.3-3.0 GHz) channel 36 (this channel was originally kind of reserved for this purpose: computers, video recorders, etc.

In times when you only had 3 terrestrial analog TV programs and not yet SCART and/or composite video inputs in your TV sets), a channel switch was not present (the corresponding hole in the CoCo's case was covered by a plate reading "Channel 36").

Some key data for PAL-G:

• Vertical scan lines: 625
• Vertical frequency: 50 Hz
• Horizontal frequency: 15.625 kHz
• Video band-width: 5.0 MHz
• Audio carrier: 5.5 MHz
• Color subcarrier frequency: 4.43361875 MHz
• Channel spacing: 8 MHz
• Vision modulation type: AM
• Vision modulation polarity: negative
• Sound modulation: FM
• Vestigial side-band: 0.75 MHz
• Field period: 1/50 s = 20 ms

United Kingdom

There's another type sold in the United Kingdom (Great Britain [England, Scotland, Wales] and Northern Ireland), I assume this one follows PAL-I standard (difference to PAL G: Video band-width is 5.5 Mhz [instead of 5.0 MHz], Vestigial side-band is 1.25 MHz [instead of 0.75 MHz] and the audio carrier is at 6.0 MHz [instead of 5.5 Mhz]). The latter has the effect, that on a PAL G TV you can either have the sound correctly tuned or the image. It was rather using VHF (0.03-0.3 GHz) [instead of UHF], so it had the "Channel 3(?) or 4(?)" select switch.

Australia

From Australia, I got at least some PAL CoCo3. The PAL CoCo3 had never been sold in Europe because Tandy / RadioShack closed its stores in the time the CoCo3 came out. The CoCo2B [lower-case, 6847-T1 VDG] was never officially available in Germany, but I got one with a very low serial number which was a demonstrator from our local store). Australia has PAL B/G, and AFAIR the machines have the VHF "channel 2(?) & 3(?)" switches, so I assume CoCo3s are PAL-B machines. However, you would rather use the composite video out or the RGB out with a CoCo 3 and not the RF modulator. Composite video out is generated from the RGB out with a piggy-backed satellite board, the GIME's NTSC composite out is not connected on PAL boards. The PAL CoCo3 has a modified PAL ROM too (initializing the GIME to 50Hz video timing).

France

The strangest group of machines (CoCo1 to CoCo2B) come from France. These have a French AZERTY keyboard layout [instead of QWERTY in both the US and the rest of Europe, at least in Germany a QWERTZ layout would have been preferred, but none cared :-)]. The modulator has been completely replaced by a VDG to RGB circuit, which is compatible with the French SECAM-L TVs. For the sake of completeness, a SECAM-L RF modulator would have to comply with the following (I think they were sold as an external device):

• Vertical scan lines: 625
• Vertical frequency: 50 Hz
• Horizontal frequency: 15.625 kHz
• Video band-width: 6.0 MHz
• Audio carrier: 6.5 MHz
• Color subcarrier frequency: 4.406250 MHz/ 4.250 MHz
• Channel spacing: 8 MHz
• Vision modulation type: AM
• Vision modulation polarity: positive
• Sound modulation: AM
• Vestigial side-band: 1.25 MHz
• Field period: 1/50 s = 20 ms

The French CoCo PCBs have an additional +12V voltage generator on board, which is output along with R, G, B, H+V (which is AFAIR actually a composite sync signal) on a small Mini-DIN connector. Then you need a special Mini-DIN to Péritel (=Euro-SCART) cable, which contains a voltage divider to create switch voltages which set the video sink (the TV) to RGB mode (rest-of-Europe SCART often runs on composite video mode only).