Date: 2004-01-16 01:34:07
Excellent point, David. Here is an amended schematic, that takes your note into consideration. Further suggestions welcome. mario > -----Original Message----- > From: firstname.lastname@example.org > [mailto:email@example.com]On Behalf Of ext David Wood > Sent: 12 January, 2004 13:47 > To: firstname.lastname@example.org > Subject: RE: C64 power supply replacement > > > The primary reason for separate windings, as far as I know, is to get > isolation between the +5 ground and the 9vac. The SX-64 user > port is known > for not working with certain devices because it's not > isloated like the > breadbox psu is. > > -David > > On Mon, 12 Jan 2004 Gianmario.Scotti@nokia.com wrote: > > > I actually knew that the transformer in the original C-64 > PSU has a transformer with two windings, but I am not sure > that's really necessary. I think a single winding would be > adequate, given enough VA of the transformer. If that's not > the case, I'd like to hear why. > > > > In any case, it's really trivial to use two windings > instead of one, in the design I presented. It doesn't > increase complexity at all. When I get home I'll prepare > another schematic, to work with commodore's original transformer. > > > > > > cheers! > > > > > > mario > > > > > > > > > > -----Original Message----- > > From: email@example.com > > [mailto:firstname.lastname@example.org]On Behalf Of ext > Hársfalvi Levente > > Sent: 12. January 2004 11:50 > > To: email@example.com > > Subject: Re: C64 power supply replacement > > > > > > Hi!, > > > > > > Gianmario.Scotti@nokia.com wrote: > > > > > A transformer doesn't have separate taps for 9 V AC *AND* > regulated 5 V :o) > > > And I did put a fuse in the 9 V AC line in the schematic. > > > > The transformer in the C64 PSU has two independent > secondary circuits, 9V AC > > each. One of these circuits is rectified and regulated (5V > DC), the other is > > just brought to the C64 (only a fuse is used). > > > > See these schematics: > > > > > http://www.funet.fi/pub/cbm/schematics/computers/c64/c64-power supply.gif > http://www.funet.fi/pub/cbm/schematics/computers/c64/c64extps.gif > > As you see, the two outputs (5V dc, 9V ac) are fully "independent" in the > original PSU design. They aren't grounded together in the PSU. > > > Regards, > > L. > > > > Message was sent through the cbm-hackers mailing list > > > Message was sent through the cbm-hackers mailing list > Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing list
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