Oric PSU jack plug is 2.1mm internal diameter
Posted: Wed Jun 22, 2022 5:25 pm
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!
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!