[1000mp] Mki V problems

[Denis Coolican]

I can appreciate the problem you are having with your mark V. The Mark V uses 12v and 30v DC to run it.  12v will run the receiver and it I draws less than 3 amps at 12 volts.  The Mark V power supply produces a 30 volt output.  Off of the 30v output there is a 12v regulator that provides the 12 volts for the receiver. The 30 volts is used for the transmitter. So the cable coming from the Mark V power supply carries 12v and a 30 volt supply as well as a switched connection to turn the power supply on and off.

I had trouble with the Mark V power supply and had to replaced the 12 volt regulator. There was a 10 pin chip in there that produces the dual outputs that feeds the switching transistors that produce the 30volt.  That 10 pin chip is hard to get and fairly expensive (70 to 100 dollars).  I did not replace this defective chip.

I wired up a 12 volt external analog supply and a  30 volt 20 amp analog supply and connected it into the rig with the cable that was previously going to the transceiver from the power supply. The analog supplies are more reliable than the switching power supplies. 

Denis ve6aq