Going from 2500 watts to 50,000 watts ERP is no walk in the park. Add to this the fact that you purchased a used transmitter at a different frequency than what you're suppose to be at. All this adds up to a can of exploding worms. We had this issue to deal with when a station at 92.7 FM went to 50,000 watts. The owner thought he'd save some money (which is not that bad of an idea) and purchased an older Energy Onix ECO 15 that had been operating at 101.9 FM. It was our job to rebuild and re-tune the transmitter.
The transmitter had been brought in and set in place with the electrical run into the HV cabinet before we even got there. We later found out that the AC power coming from the pole wasn't supplying enough current to the building. The lights would dim when the transmitter was on, so we called the power company back out and had them replace the transformer and power lines.
Notice the lovely chipboard box in back of the transmitter? Believe it or not, that was the owners idea of a fresh air duct.
Second view of used transmitter. HV cabinet is to the left. Also note the heliax line coming into the room from the upper right. This looped around the ceiling throughout the building instead of being trimmed to the proper length.
Also note the PA exhaust pipe at the top. The owner just wanted to leave it like this. Yeah, that didn't happen. We ran the proper duct work and exhausted the hot air out of the building.
Another shot of the heliax looping around the room. Yes, that would be the transmitter's RF filter poking out above the door frame. We did trim the line and re-installed the RF connector properly.
The floor of the HV cabinet when we opened it up. As usual, everything is dirty and wired poorly. We cut back the high voltage wires about 5' that went to the transmitter. We found them coiled up and tie wrapped on the cabinet floor.
High voltage wiring trimmed back, cabinet cleaned and correct grounding installed.
One of the things I always check on is the condition of the high voltage wires and how they run in, around and through a transmitter. These ran along a rail inside of the HV cabinet. You can see where the wires have had a few corona discharges in the past. This happens in high voltage systems when a wires insulation starts to break down due to both time and voltage stress. Not a good situation, so we replaced them.
Another thing to always check on when buying a used transmitter is the condition of the blower vibration mounts. The people that sold the transmitter never removed the blower from the transmitter when they shipped it. Needless to say, when this ECO 15 arrived to it's new location, the blower mounts were ripped in half. Since these don't grow on trees, we created "replacements" from parts bought at the local hardware till the new ones arrived.
Always a pleasant surprise to find after opening up the PA box on a used transmitter, a damaged tube socket. Since the transmitter was taken out of service in running condition, we determined that it had been somehow vandalized while in the building waiting for us to arrive. Oddly enough there was a rival radio station's transmitter located in the same building. Very strange....
Damaged tube socket next to the new one we had shipped in next day air. Since this was a used grounded grid transmitter, we also installed new button caps.
One of the biggest problems I've had with Energy Onix's ECO transmitters is the teflon insulators they use on their PA Tune and Load adjustment knobs. The setscrews always loosen up or someone reefs on them till they strip out (which doesn't take much) and then they don't work at all. Bad design as far as I'm concerned.
Our fix, add a brass collar around the teflon with threaded holes. Stainless steel hex screws run through the teflon and hold the knob securely in place on the shaft. This works really well and it will never loosen or strip out. Also, this design will not affect anything RF wise within the PA box. Why can't transmitter companies figure this stuff out?
| While we were there and waiting for the new tube socket, we were asked to replace the old stepper motor switch system that the tower lights used. The contacts were pretty badly burnt, so it was time for this to go.  |  New solid state flashers installed for the tower lights and harness built. |
After fixing everything that was wrong with this used ECO 15 and spending five days on a project that should have only taken a maximum of a day and a half, the transmitter was re-tuned from 101.9 to 92.7 FM in only 4 hours. 11 Kwatts output power was all it took for an ERP of 50K watts.
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