Atmos Power Supply Needed

[AndyGarton]

Hi all,

I've just bought and Atmos but it doesn't have a PSU. I can't use a generic one really as I've also bought an RGB SCART lead that requires a connection to the "special" (I think?) connector on the Oric PSU (it's this one: http://www.retrocomputershack.com/PDF/Oric-Scart.pdf ).

I've searched high and low and also asked Steve from this forum but no joy so far. Help!

Cheers,
Andy

[Antiriad2097]

There's no 'special' connection on an Oric PSU, there's just a single plug. The connector on that cable will be a pass through so you connect the Oric PSU to the cable, then the 'spare' plug on the cable goes into the Oric power socket. With that in mind a generic PSU of the correct voltage and pinout will work fine. I wouldn't mind a recommendation for a 3rd party PSU myself since the wire on mine is exposed right at the join.

[AndyGarton]

Ah yes, makes sense of course, I got confused by the large round "plug", which is actually just a socket on a wire.

Regarding a generic PSU, I've bought this:

http://www.amazon.co.uk/gp/product/B002 ... UTF8&psc=1

... but don't know if it works yet, and am scared about getting the polarity wrong as electrics isn't my thing

[Dbug]

Also make sure you put something on the expansion bus: Sticky tape, empty connector, styrofoam, ... because a common way to fry an Oric is to unplug and replug on the expansion bus instead of the socket -> instant machine death.

[dave3622]

Also make sure you put something on the expansion bus: Sticky tape, empty connector, styrofoam, ... because a common way to fry an Oric is to unplug and replug on the expansion bus instead of the socket -> instant machine death.

Very good advice, I managed to fry an Atmos doing exactly this. Luckily I had a spare one but it was a hard lesson learnt.

[Chema]

Beware also that the Oric PSU has the polarity reversed. One from a zx spectrum will do, simply by cutting the cable and inverting the connections.

[AndyGarton]

Beware also that the Oric PSU has the polarity reversed. One from a zx spectrum will do, simply by cutting the cable and inverting the connections.

For a generic switchable PSU though, do I have it on positive or negative?

[Chema]

http://twilighte.oric.org/twinew/start.htm

There you have more information. If I recall correctly, you can also use a 7.5volt PSU. 600mA is enough for the Oric, but won't suffice if you want to power other devices as well, such as a disk drive. Not sure if it will be enough to use with the Scart cable, though I think it should.

[AndyGarton]

Cheers, I'm not sure exactly where to look there that answers my question though (assuming you were answering me!)? I'd already looked at that site - it gives the PSU specs required, but nothing more that I can find.

[JonB]

I use one of these:

http://www.ebay.co.uk/sch/i.html?_odkw= ... a&_sacat=0

The plug is 5.5mm / 2.1mm with a positive tip - ensure you choose the right size. Plugs straight into the Atmos, no problems. Also, I have seen some stuff about needing power for a SCART cable (I think it is to assert pin 8 which selects the input on most TVs) but I found it unnecessary on my cheapo LCD, and the picture is superb.

(Edit. Oh bother. I think I modified mine for 5v operation by bypassing the voltage regulator, so this may not be for you. But the plug size is right..)

[Chema]

Cheers, I'm not sure exactly where to look there that answers my question though (assuming you were answering me!)? I'd already looked at that site - it gives the PSU specs required, but nothing more that I can find.

Oh, I am very sorry. I think that I misunderstood your question completely. I thought you just asked if the negative voltage was in the inner or outer side of the plug... No idea what you meant by "positive or negative".

[AndyGarton]

FWIW I can confirm the generic PSU I linked above does work (and with an RGB SCART cable as well). I set it to positive 9V mode and crossed my fingers, and all was good

[Chema]

Great! Congrats!

[Antiriad2097]

Beware also that the Oric PSU has the polarity reversed. One from a zx spectrum will do, simply by cutting the cable and inverting the connections.

This I didn't know. I think I'll just knock up an adapter to plug my Speccy PSU into so I can use it with either.

[Steve M]

Also make sure you put something on the expansion bus: Sticky tape, empty connector, styrofoam, ... because a common way to fry an Oric is to unplug and replug on the expansion bus instead of the socket -> instant machine death.

I have a couple of hundred little plastic things which are exactly for this. If anyone wants some proper plastic expansion protectors, let me know.