Re: use of +12 and -5 on commodore 8032

Well, it will make it lighter and easier to move around... ;-)

But it seems like a lot of needless work and modifications to the board, especially unsoldering and replacing the memory chips, not to mention disabling the cassette drives; I don't recall ever seeing or hearing about any issues that could be traced to a power supply problem other than the inadequate connector.

As I mentioned before, with all the boost and buck converters these days you could presumably provide all the necessary voltages from a single 12V or 5V switching supply and not touch the PET board at all, or just modify a standard PC supply to raise the voltages as required.

But a chacun son gout...

m
  ----- Original Message ----- 
  From: Justin Cordesman 
  To: cbm-hackers@musoftware.de 
  Sent: Wednesday, September 07, 2016 1:32 PM
  Subject: Re: use of +12 and -5 on commodore 8032


  I think this is a good idea too. A modern efficient power supply and voltage regulator would not hurt at all. I suspect that tighter regulation and less heat would improve service life on almost every other component.

  Justin

  On Sep 7, 2016, at 12:09, Mike Stein <mhs.stein@gmail.com> wrote:


    Sounds OK but seems like a lot of trouble and mods; why?

    m

    ----- Original Message ----- 
    From: "Didier Derny" <didier@aida.org>
    To: <cbm-hackers@musoftware.de>
    Sent: Wednesday, September 07, 2016 7:29 AM
    Subject: use of +12 and -5 on commodore 8032


    > Hi
    > 
    > any idea if  +12v and -5v are used for anything else than  the 4116 ?
    > 
    > the idea:
    > all original  regulator removed (easy to put back in place)   (+5 +12 -5 
    > disconnected from the original power supply)
    > +5v regulated directly injected on the motherboard
    > +12V connected to +5v regulated  (strap between the 2 regulator output )
    > 4164 installed in place of 4116
    > 
    > the 4164 would get 5v by the 12v track (now 5v with the modification)
    > pin 1  -5v  not connected (-5v removed)
    > pin 8  +5v (+5v coming by 12v track)
    > pin 9  A7  (forced to 5v by 5v track)
    > 
    > seems similar on some modification made on atari
    > 
    > may any potential side effect on some other part of the system...
    > I dont see any real use of the +12v and -5v except for the 4116
    > but I might have missed something
    > 
    > for the +9v unregulated I never found any used except for the tape
    > but I'll probably never use a commodore tape...
    > 
    > the main idea is to avoid any permanent modification on the board...
    > --
    > didier
    > 
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