Charles Gutman  wrote:   
   > My 128 is not getting power through the expansion port. No game   
   > cartridges work, Ramlink won't power up (Just had it fully   
   > tested and it works perfectly).   
   > Also the 128 powers and loads and runs perfectly from the   
   > serial port.   
      
   So 5V power is available to all of the other 5VDC outputs on   
   other ports of the C128?   
      
   > I did a reference check and found that the 5vdc output to   
   > the port are located at pin 2 and pin 3 respectively. Thus,   
   > would it be considered "safe"  to run jumpers from the User   
   > port and from the cassette port to pins2and 3 of the expansion   
   > port to power it up so I can run my carts?   
      
   The reference I have for the C64 Expansion Port (AKA User Port),   
   which I think is the same as the C128's, shows that pin 2 is the   
   only 5VDC connection. Pin 3 is an active low input for the reset   
   signal. That means it is held high at 5V, but only so that it can   
   be shorted out on purpose in order for a device to tell the   
   computer to reset. It would not work for power because it will   
   not be designed to supply significant current.   
      
   If both pin 2 and pin 3 are not at 5V, this likely means that the   
   expansion port connector has broken, or the C128 circuit board has   
   broken near the connector. This has severed some of the connections   
   between the port and the computer. Power could be connected directly   
   to pin 2 from the cassette port without risk, however as more than   
   one pin is known to be damaged, it is likely that there will be   
   broken connections on data lines as well; to fix these will require   
   repair of the circuit board or connector inside the computer.   
      
   Pin 3 should not be brought high via a wire. It is only commonly used   
   by reset switches on cartridges and leaving it in its disconnected   
   state will not affect operation of the user port. Connecting it to   
   direct 5VDC is not likely to cause damage, but damage is possible   
   if the input goes to a Standard TTL type chip inside the computer.   
      
   If only pin 2 is not at 5VDC, then the failure may be due to a   
   burnt-out track on the circuit board caused by plugging in a faulty   
   cartridge, or otherwise shorting out the power at the port. Power   
   could be restored directly from another of the computer's 5VDC   
   outputs, however care should be taken that the offending cartridge   
   or action which caused the failure is not repeated, because this   
   could cause more severe damage than in the first occourance.   
      
   If your diagnosis of a lack of power to pins 2 and 3 is based   
   solely on the failure of the port to function, rather than actual   
   voltage measurements, I recommend you perform direct measurements   
   before taking any action.   
      
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