Re: Re: C-64 with no 9v possible failures?
  By: Computer Nerd Kev to Keith Matthews on Sun Nov 08 2015 01:20:47

Hi Kev,

 > Keith Matthews 
wrote:
 > > Hi All,
 > >
 > > I have a breadbox style C-64 that has stopped working.
 > > I connected my 1501 Power Monitor to the Power Supply and it
 > > seems fine for both 5v and 9v (well it shows 10v)
 > >
 > > The Power Supply work fine with my C64C machine.
 > >
 > > I connect the 1501 Power Monitor to the User Port and I
 > > only get the 5v indication
 > >
 > > There does not seem to be 9v at the user port.
 > > I have pressed in all the chips and checked the internal fuse on the C-64.
 > 
 > If the power supply 9V voltages are alright when used with your C64C, but
 > drop when used with this one, it could be due to a short in the computer
 > causing excessive load and in turn the 9V voltage to drop below that
 > required by the computer. That could be due to a failed capator or other
 > component connected to the 9V supply.
 > 
 > Also use a multimeter in its lowest resistance mode to check that there
 > is very low resistace between the 9V pins of the power plug at the back
 > of the computer, and the 9V pins of the User Port.
 > 
 > There are a pair of pins to check for this:
 > Power pin 7 to User Port pin 11
 > Power pin 6 to user Port pin 10
 > 
 > If there is more than a few ohms resistance, there could be a partial
 > or complete break in the circuit board, or in the connection for the
 > power plug.
 > 
 > If it is a low resistance, but the 9V voltage reading is low when the
 > computer is on, then a component failure or other short inside the
 > computer is likely.
 > 
 > If the 9V fuse in the computer hasn't blown, you might try removing it
 > and connecting your multimeter in its highest current measureing range
 > across the fuse terminals. With the computer breifly switched on, you
 > may observe the current above or near the 1A maximum rating which would
 > indicate a short or component failure. This test should be breif, as the
 > excessive load does risk overheating the transformer in the power
 > supply.

Thanks heaps for all those great pointer. 8-)

I'll have a look into them this weekend. 8-)

Thx again.


 > 
 > --
 > __          __
 > #_ < |\| |< _#
 > 
--------------------------------------
Regards........Geo
oooOOOooo
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