Warner FMT 5.0
The 150 Watt transmitter came in today with a report that it was overheating after being on for a short while. Not familiar with this transmitter, so off with it’s lid to see what was hiding inside.
The unit is built into a 1U high rack mount chassis. All very neat and tidy inside, nice layout and looking very professional. Access to all modules is easy. A pleasant surprise for a change!
The cause of the overheating was quite obvious. There are 4 fan blowers situated at the front, blowing air over the large heatsink of the pallet amplifier. All the fans and surrounding area were totally blocked with a carpet of sticky soot. The fans were jammed and could not run. The whole thing smelt as if it had lived in a 1950s smoking man’s club where Balkan mix pipe tobacco was the order of the day. The fan assembly was removed, along with the pallet module for a full clean up. A small bag of matted gunk was removed. With everything clean, a semi reassemble and test. A power meter and dummy load connected. On power up, the LCD display tells you what’s happening and the output is ramped up over a period of 10 seconds or so. Full output was obtained, so an audio source connected to see what the received signal was like. Whilst we had full power, no modulation, dead air. The cause was a bad connection on a ribbon cable connecting the audio processor to the front panel where the LCD and exciter live. With this cleaned, we had good audio. Very clean sounding, no pilot noise and good channel separation. Spectrum analyser should really low harmonics. Run the transmitter at full power for two hours to monitor the pallet temperature. With an ambient of 22 degrees, we managed to reach 31 degrees increase. Very respectable indeed. A very efficient transmitter.
All packed up and ready to be collected. Have to say, a very nice piece of kit.
Glad you sorted it…. Probably nice for you to find a different “challenge”
J’ai acheté cet émetteur, il y a trois ans à peine maintenant, il a cessé de fonctionner. Après les diagononostics, on a trouvé que le transistor de puissance est grillé.cela causait un cuir-circuit. Lorsqu’on a enlevé le transistor de puissance, l’émetteur fonctionne mais sans puissance. On a changé le transistor de puissance, une minute après, le deuxième transistor tout neuf est grillé causant le cuir-circuit. Ma question où est le problème ? Pourquoi le transistor de puissance grille? Trouvez moi une solution s’il vous plaît !