Commodore Sx 64 help please - UK Vintage Radio Repair and Restoration Discussion Forum

pudwink · 4th Mar 2024, 3:17 pm

Hi all
I wonder if anyone can help me I have a UK sx64 computer which boots up but the disc drive does not work and it is missing its outer case.
So at great expense I have a US version on its way from the States, my question is could I use the UK power supply off mine and plug it in to the US one to save having to source a stepdown converter to test it out.
And are the boards inside the US one the same as the UK one so hopefully I can get the disk drive working between the two.
Many thanks

ortek_service · 5th Mar 2024, 10:52 am

Surprisingly, finding details on the USA version PSU seems rather tricky - Zimmers only seem to have European voltage version schematics / Tech Man: http://www.zimmers.net/anonftp/pub/c...-64/index.html
- With the Tech Man also having details on the FDD, in case that's fixable. However, it only mentioned Alps mechanisms, of which 1541 ones had alignment issues rather than the 1541 etc Newtronics ones that often suffered from 'wire rot' in the heads: https://en.wikipedia.org/wiki/Commodore_1541

And although the SX-64 has got an SMPSU in it, it seems this isn't designed to be dual-voltage compatible - especially as it also has some small convention 50Hz transformers that only have a single primary winding.
So not easy to convert one, as discussed here: https://comp.sys.cbm.narkive.com/CGh...transformation
But if the boards are the same size between the USA & Europe models, then it may be possible to swap them over - or maybe just swap the FDD over, if that's the real problem?

pudwink · 5th Mar 2024, 6:59 pm

Hi
Thank you for replying to my post I just thought as the power supplys should have all the same connectors I would presume that it would have the same voltages coming out of them just that the UK and USA power supplies have different input voltages from the mains would the UK one being 50Hz instead of the usa 60Hz cause any issues .

ortek_service · 6th Mar 2024, 1:07 am

Quote:

Originally Posted by pudwink

>>
>>
would the UK one being 50Hz instead of the usa 60Hz cause any issues .

It shouldn't really make much difference, as the PSU board itself will have been designed for the right input frequency & voltage and the computer won't see the input-frequency on the DC voltages.
Plus AC voltage outputs from the PSU - I think the C64 had 9Vac to feed to the Datasette etc - would be just used to power motors in that.

4th Mar 2024, 3:17 pm	#1
pudwink Pentode Join Date: Jan 2011 Location: Nottingham, Notts. UK. Posts: 207	Commodore Sx 64 help please Hi all I wonder if anyone can help me I have a UK sx64 computer which boots up but the disc drive does not work and it is missing its outer case. So at great expense I have a US version on its way from the States, my question is could I use the UK power supply off mine and plug it in to the US one to save having to source a stepdown converter to test it out. And are the boards inside the US one the same as the UK one so hopefully I can get the disk drive working between the two. Many thanks

5th Mar 2024, 10:52 am	#2
ortek_service Octode Join Date: May 2018 Location: Northampton, Northamptonshire, UK. Posts: 1,454	Re: Commodore Sx 64 help please Surprisingly, finding details on the USA version PSU seems rather tricky - Zimmers only seem to have European voltage version schematics / Tech Man: http://www.zimmers.net/anonftp/pub/c...-64/index.html - With the Tech Man also having details on the FDD, in case that's fixable. However, it only mentioned Alps mechanisms, of which 1541 ones had alignment issues rather than the 1541 etc Newtronics ones that often suffered from 'wire rot' in the heads: https://en.wikipedia.org/wiki/Commodore_1541 And although the SX-64 has got an SMPSU in it, it seems this isn't designed to be dual-voltage compatible - especially as it also has some small convention 50Hz transformers that only have a single primary winding. So not easy to convert one, as discussed here: https://comp.sys.cbm.narkive.com/CGh...transformation But if the boards are the same size between the USA & Europe models, then it may be possible to swap them over - or maybe just swap the FDD over, if that's the real problem?

5th Mar 2024, 6:59 pm	#3
pudwink Pentode Join Date: Jan 2011 Location: Nottingham, Notts. UK. Posts: 207	Re: Commodore Sx 64 help please Hi Thank you for replying to my post I just thought as the power supplys should have all the same connectors I would presume that it would have the same voltages coming out of them just that the UK and USA power supplies have different input voltages from the mains would the UK one being 50Hz instead of the usa 60Hz cause any issues .