Kenpro KR-400C Rotator Controller
I bought a Kenpro rotator at the Reading rally and found that on testing everything worked, except the dial didn't go round! Grumble moan, loads of googling - found an article by G8MNY about the same problem - the small spur gear on the motor shaft had cracked along its length, causing it to jam on the subsequently opened up section of the teeth. He suggested gluing, which I tried but with no success. The nylon (delrin) gear is just an interference fit so that in the case of anything going awry it spins on the shaft if it meets a jam. Guess it'd jammed once to many times! Found a guy (G3IBI) advertising rotator spares but he had plenty of motors, no gears.
So, knowing that Yaesu bought out Kenpro, I rang Yaesu spares. It transpired that the docs they had relating to the equivalent G-400RC were of a different design with belts (like the Daiwa).They were the only docs they had passed to them from Japan on the takeover, so snookered again!
Started looking at gear suppliers/manufacturers and after a very long internet session, and a quick learning session on how gears are specified, managed to find a delrin gear by HPC gears in Chesterfield*. The reference is ZGO.5-14 and it's about 4 quid. The postage however was £7.50!! No other options so I stumped up for two....
The bore on the gear is 2mm, so I carefully drilled out to 3mm (2.8 actually) and lo and behold it was a good tight fit. Had to adjust the feedback pot to let it know where it was pointing and away it went! At the same time I put a resistor in series with the lamp to prolong its life as per G8MNY's article. He also suggests a .47 uF 300V AC cap across the mains input to power factor correct the permanent transformer load. I didn't have one of that rating in the spares box so I'll leave that till I pick one up. I taped my spare gear to the motor so I won't lose it.
Next was attaching the rotator to my little push-up mast. The top section is only 32mm diam and my previous cheapo rotator had been attached alongside with clamps. Fortunately there was a small plate (60mm) on top of the section and so I made up a plate out of an old equipment rack I cut up with an electric cutter/grinder, drilled for the 3 screws on the mast plate, and the 4 bolts on the bottom of the rotator. Took a little work with a ruler, scriber and compass (you can see my compass scribings on the pic). Works great with my lightweight (9 ele) for 2m, and hopefully I won't have to keep dashing out at the next UKACC to check it's pointing in the right direction :)
* HPC Gears: 01246 268080 www.hpcgears.com
