The Johnsons

In January, 2013 the power transformer in the Johnson Adventurer, the AM exciter in the auxillary AM transmitter, failed filling the transmitter room with thick, black smoke. This started me on a project to fix several transmitters that were in non working or unknown condition.

This is a spare Johnson Adventurer that was given to me. It was rumored that the power transformer was bad.

With it's cabinet removed, this is what the Adventurer looks like. The transmitter is simply an 807 driven by a 6AG7 with a 5U4 power supply.

This is the bottom of the transmitter. Yes mess. Remember, this transmitter was only available in kit form. Just about every one was built by a novice as their first transmitter. This one also has mods for an external VFO and T/R switching. I'll do a quick clean up, fix the cold solder connections, etc.

Up, running and lighting a 100 watt light bulb as a dummy load. It turned out the power transformer was good. The cold solder connections have been fixed. The T/R relay was rewired. Plain wire has been replaced by... yes, 1/4 inch heliax. Why? It was the first 50 ohm cable I could grab in the closet, it was easy to work with and I thought it was kinda cool. The keying line was wired through the relays second set of contacts. Before you could key up the transmitter in the receive position with no load. The input ac terminal strip was broken potentially shorting out the 110 vac input. That was replaced and a new line cord installed. Once it's put back in its cabinet this unit will be ready to be installed in the station.

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