Mosquito Magnet Forum

Knock on wood, I think I've got my MM Defender working and discovered a new problem and solution.

So I picked up a MM Defender off of craigslist for cheap (knowing the problems that these units have after the first year). When I got it home, I had the standard problems; the unit would turn on, run for about 30 minutes, then power off again with the flashing error sign.

Checking the tank with a pressure gauge, I verified that the unit was actually consuming propane. I tried the default cleaning with the CO2 cartridges, tank rest tool, etc with no change.

Next, opened it up, replaced the missing nylon screw for the thermister. After this, the unit was powering up but was dying in the mid-day heat and wouldn't restart till about 6pm. Next, opened up the aluminum casing, disassembled the nozzle and cleaned it completely. Verified that the valve was opening and closing correctly. After this, the unit actually got much worse, only working for 30 minutes before going into the flashing shutdown mode. That said, I had verified working all the mechanical elements. The ignitor gets hot, propane flows, the catalyzer seems to be catalyzing, etc.

All that was left is the electronics. The circuit board looked not particularly great, so I reflowed the solder on any joints that looked bad. In addition, I had had a problem with the fan connection not working without jiggling the connector, so I also removed the leads from the plastic connectors and cleaned them up, removing the oxidation and such from the contacts of all the leads. They actually looked really badly oxidized. After reassembly, the unit powered up and ran starting about midday today and hasn't errorred out again. So for people with problems that don't seem to go away or make any sense, I'd recommend cleaning all the contacts or resoldering any points on the board that look like the board might be hinky.

oh and thanks to everyone for all the info on these boards