re ampli-bus circuit theoric #28

This is the right place to discuss on how to implement hardware vsync, adding a VIA or AY chipset, puting multiple roms, or how to design a new flash expansion card.
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re ampli-bus circuit theoric #28

Post by jdavis6809 » Mon May 11, 2015 12:59 pm


I have downloaded all the theoric magazines

found a copy of the amplibus circuit in issue #28

see attached
Théoric 028 - Page 039 (1987-02) ampli-bus 1.jpg
Théoric 028 - Page 040 (1987-02) ampli-bus 2.jpg

john davis uk

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Re: re ampli-bus circuit theoric #28

Post by Dbug » Mon May 11, 2015 8:54 pm

Please, stop posting messages with copies of things already available: ... ric-28.pdf
Just link to the files and indicate which page the interesting part is, and do that on threads that are in context.

I will delete the next similar messages

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Re: re ampli-bus circuit theoric #28

Post by Steve M » Thu Jun 18, 2015 12:44 pm

A translation. (I think)

Oric Bus Amplifier

The original Oric expansion bus is not amplified, and certain of the signal, especially that of the clock which times the whole ensemble, are already in considerable demand. Because of this, when you attach a peripheral to the bus, the signals are not strong enough to be accurate, and produce false information due to desynchronisation.

That is why you can no longer load a program from cassette, or why your screen goes haywire or gives odd error messages. Hang-up of the keyboard or computer can occur, and you may well unjustly blame the peripheral, which is not in fact responsible, particularly if the oddities are not present when the peripheral is disconnected.

The bus amplifier is not simply a socket, but an active unit. It cleans and amplifies the necessary signals, especially the clock signal. As the bus is now amplified, you can connect up to 3 peripherals at once to the three expansion port connections of the bus amplifier.

- Check that your computer and peripherals are all switched off, or risk serious damage !
- Disconnect any peripherals from the expansion bus.
- Insert the female 34-pin plug of the bus amplifier into the extension port of the Oric.
- You now have three male sockets to connect you chosen three peripherals, providing of course that have the corresponding female connectors. If not, get adaptors.
- A special connection or inverter serves specially to filter the clock signal. When this switch is switched towards the centre of the circuit board, the clock signal is strongly filtered; this should be used as a last resort. However, in this mode you risk 'zebra stripes' on screen.,
- Switch everything on again.

Don't forget a true earth pin is vital to the proper functioning of your system.

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