Hi Gerrit, That is strange because I have measured an old C64 power supply and other plus4 power supplies which provide 5.4v. The plus4 power supply schematic diagram says 5.2v though. I have checked the CPU datasheet and it says max voltage is 7v but of course the other components might not like it. I know the regulator you linked here but that still needs the diode bridges and the 4700uF capacitor (I believe). The heat is generated by the 7805 regulator so you are right it will be cooler (and maybe more stable). Istvan -----Original Message----- From: Gerrit Heitsch Sent: Wednesday, September 19, 2012 9:40 PM To: firstname.lastname@example.org Subject: Re: plus4 power supply On 09/19/2012 09:25 PM, Hegedűs István wrote: > Hi, > I have done a major repair service on my plus4 power supply. Replaced > the electrolyte and tantal capacitors, the diodes. Now it supplies 5.6v > while before it supplied 5.4v. Is it dangerous for the plus4? What > should be the voltage level of a normal power supply? (Note that I have > only a multimeter and no scope so might be measurement difference). It shouldn't go above 5.2V. You should do a complete rework of the power supply remove the existing regulator, get a switching regulator, for example http://www.ebay.de/itm/290572036224 This one is adjustable, so adjust to 5.2V _before_ connecting the Plus/4. As a sideeffekt, the PSU will run much cooler. If you feel _really_ adventurous, you can put a complete switching power supply that runs on 230V and supplies 5V 2A into the empty part of the Plus/4 PSU. The transformer will then only be used for 9V AC. But since one has to work on 230V AC, this is only for people who know exactly what they're doing. Gerrit Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2012-09-20 12:00:04
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