Oric PSU jack plug is 2.1mm internal diameter

[Jonh]

I recently was looking for a new PSU, and faithfully followed the spec in the Oric Service Manual and on our Wiki, namely that the internal diameter of the jack plug is 2.5mm. A nice new PSU arrived, but was a very wobbly fit and didn't power up the Atmos.

That set me to checking - this can most easily be done with drill bits. A 2.4mm drill fitted snugly in the new PSU with a 2.5mm jack - but was too large for the original Oric PSU. A 2mm bit, however, fitted snugly into the Oric PSU jack. You can also test with a cocktail stick with the point snipped off - it's diameter is around 2mm - and see the difference, it pretty well holds in the Oric PSU jack when held vertically, whereas in a 2.5mm jack it just drops out

So I ordered the same modern PSU but with a 2.1mm jack, and it fitted and powered up the Oric perfectly. So beware, our documentation is wrong, the internal diameter of the jack plug needed for an Oric is 2.1mm, centre positive of course.

The unit I bought is 9v, 1 amp, with a UK plug - https://cpc.farnell.com/pro-elec/pell00 ... dp/PW04603 for UK users, £5.94 each. The barrel length is 12mm, identical to the Oric PSU.

How has no-one noticed over the last 30+ years?! Perhaps because the Oric PSUs roll on for ever!

[iss]

IIRC this was discussed already, unfortunately I can't find the old posts because the search doesn't work atm.
I need to check but I'm pretty sure that I have PCB's with both 2.1mm and 2.5mm jacks.
Maybe nowadays the best is to buy new connectors and replace them both .

[Jonh]

Is this the thread you are referring to?

https://forum.defence-force.org/viewtop ... 536#p14536

So far I've checked 3 Atmoses (Atmoi ?) and one Oric-1, all are 2.1mm - more to follow

[Jonh]

Sorry to keep on about this, but I do think the Wiki is misleading and should be amended. I've now checked 6 machines, all 2.1mm.

And this from the owner of Retro Computer Shack, who has sold no less than 808 SCART (Peritel) powered leads for the Oric:

[iss]

Actually , there is no disagreement. The 2.1mm female plug of the PSU definitely will make better connection.
If it's tight this will be only the first time .