ncoplin_at_orbeng.com
Date: 2004-01-15 10:16:01
Hi Mike, There is presently a commercial product that does this - called SuperPSU and is distributed by http://www.commodorescene.org.uk/ . The one PSU can also power the various CMD products. I assume it outputs the necessary 9VAC too, but the description doesn't say specifically.... - Nick -----Original Message----- From: Mike Paull [mailto:mpaull@optusnet.com.au] Sent: Thursday, 15 January 2004 4:47 PM To: cbm-hackers@cling.gu.se Subject: Re: C64 power supply replacement Has anyone else come up with a design we can build that lets us use a PC power supply to power the C64? Personally I prefer this option because we can power our disk drives too. And as for noisey fans, don't be tight with the $$$ and buy a decent PSU and you won't have a noisey fan. As for bulk, well i'd rather have ONE PC power supply instead of six or seven brick power supplies. Mike On Sun, 11 Jan 2004 13:11:10 +0200, you wrote: >I must object to that design. Not only is it more complex and expensive than the one I presented earlier, it also has an excellent chance of frying your C-64! Let's analize the circuit for a moment, shall we? The schematic is http://www.volny.cz/dundera/power_sch.pdf > >- it contains 2 integrated circuits and 6 (!!) bipolar transistors. >- if ANY of the active components mentioned above barfs, you end up with a constantly positive or constantly negative +12 or -12 V DC instead of 9 V AC - and since you depend on the functioning of 8 active elements in switching mode, your chances are very good (or bad, depending on your point of view). > >Other disadvantages include: >- Requires more conponents AND it still requires the PC power supply. It will be bulky AND it will be noisy (fans in the PC PSU)! >- Produces a SQUARE wave instead of a sine, for the 9 V AC. I don't know about you, but I won't be powering my C-64 with a square wave, even if it survives the first few days. >- The frequency of the wave is not steady, as it is produced with a simple RC element. Sure, it might work at the beginning, when you construct the device, but wait till it's a warmer day, or a colder day, or heck, if the humidity is much higher or lower.... >- The BD135/BD136 transistors are subject to considerable stress. They will definitely produce heat and will be a good candidates for crapping out one nice day. > >In comparison, the design I presented is much simpler, it will never fry your C-64 (it uses the 7805, which has protective circuitry to protect itself and the target, and it's virtually impossible to damage), it has only 1 active component (the 7805), it's silent (no fans), it "produces" a 9V sine wave, as the original PSU and at the correct frequency. The only active element to warm up is the 7805, which, as I already said, contains protective circuitry that saves it from overheating as well. The only disadvantage of my design would be that youneed a 220/9V transformer, but I suspect you could use the one from the original C-64 PSU. > > > > >> -----Original Message----- >> From: owner-cbm-hackers@cling.gu.se >> [mailto:owner-cbm-hackers@cling.gu.se]On Behalf Of ext Luca >> Di Pasquale >> Sent: 11 January, 2004 12:03 >> To: cbm-hackers@cling.gu.se >> Subject: Re: C64 power supply replacement >> >> >> Just change a resistor and a capacitor (R1 and C1 in that >> project) and you >> will magically get the 60 hz needed on NTSC C64's (and >> finally get rid of the >> shitty C64 power supply!) :-) >> >> Ciao, >> Luca >> >> > Remember that that is 50hz so in the non-PAL C64 your >> clocks will be >> > wrong including the CIA timers which get their frequency from the >> > 9VAC. >> > >> > --Ray >> > >> > >For anyone looking at replacing a C64 power supply with >> one from a PC >> > have >> > >a look at this web page; >> > > >> > >http://www.volny.cz/dundera/stuff.html >> > > >> > >This is the IDE64 home page however they have a nice >> little DC to AC >> > >circuit so you can power your C64 from the one power >> source instead of >> > >having one for ac and one for dc. >> > > >> > >I haven't built it yet so I can't say anything about it's >> reliability or >> > >design. >> > > >> > >Mike >> >> >> 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Your Engineering Solutions Provider http://www.orbeng.com.au/orbital/engineeringServices/engServices.htm - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - PLEASE TAKE NOTE: The contents of this email (including any attachments) may be privileged and confidential. 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