This is a description & backgrounder on the upcoming transmitter replacement and the problems we had in the last weeks. The plan was to pick-up the transmitter in Toronto on Wednesday (26 Feb 96) evening and to put it in place and do a little testing the next day. Unfortunately, during high power testing a problem in the transmitter's power supply unit (PSU) surfaced, postponing the change over schedule until a repair could be effected. The new transmitter is in fact a slightly used unit. It was manufactured in England and shipped to the US to be 'reverse engineered' providing the information needed to engineer and manufacture a subsequent 'generation' of transmitters. The power supply converts the 'mains' supply of 120 volts to that needed by the transmitter components. There's a power supply unit in computers, radios and just about any other electronics. The little adapter which you can plug into the wall outlet with a plug which connects to a radio is a power supply. For a small radio the power supply might convert 120 volts AC (VAC) to 6 volts DC (VDC) - the equivalent of four batteries. The power supply for the transmitter is designed to convert 120 VAC to 28 VDC and provide 30 amps of current to drive the transmitter. This is about 1,000 watts of power or the equivalent of about 700 of those little 6 volt units used to drive the radio described above. A common component used in making power supplies is an electrolytic capacitor which often takes the form of a shiny tin can with wires coming out of the top and bottom. These devices 'smooth' out the alternating current in the conversion to direct current and can 'dry out' over time and loose their capacitance. When certain components in a PSU fail, undesirably high currents can can be generated which will weaken or damage other parts. Since discovering the problem the transmitter vendor has agreed to drop the price by $1,000US from $3,800US - and this should be enough to cover the cost of repair, without going over budget. Our problem is time. I am hoping that the power supply repairs made today will allow "burn in" testing of the whole transmitter system over the weekend. During this time the transmitter will be set up and run at little more than full power around the clock for four or five days ... better that we can find the problems and resolve them in the lab, than having trouble after the change over. If all goes well this should avoid having to send the PSU to California adding a further delay. Our new testing day of 2 Apr 97 is booked with Industry Canada (the government folks), and we'll have a fair amount of work to do to have the transmitter ready and the new antenna hung and ready to met that date. If you have any questions of this or anything else related to the project, please let me know. best // jkm FREQ & POWER BULLETIN - 13 MARCH 97