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  • Topic: Installing RCS R/C and batteries into the LGB Mikado

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    • February 11, 2006 4:57 AM EST

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      Recently a very good RCS customer here in Australia asked me to convert an LGB Mikado to battery R/C. Part of the specs were that he wanted to retain the excellent LGB sound and the way that it worked such as the two toots of the whistle for forwards and three for reverse. Plus he wanted to have the RCS sound trigger functions also work the regular reed switch triggers. It actually took two attempts to get the installation right. The first time it all went together just fine with all the equipment in the boiler and the batteries in the tender. Problem was the range at about 20' was not very good. To solve the range problem I had my customer return the loco for modification. I removed the RF-RX part and antenna from the boiler where the LGB sound was causing RF Interference and relocated them to the tender shell. This solved the problem and the range is now over 100'. Some of the pics were taken during the first version so do not show the modifications to RCS components in the boiler. This was the very first time I had seen an LGB Mikado so the the hardest part of the conversion was figuring out how to get the loco apart. With a little help from Dave Goodson I soon had that problem solved. The first part of this "How I did it" are a series of pics with arrows pointing out which screws need to be removed. I recommend placing the loco upside down in the top of the foam packing. This will help protect the loco from any damage during handling. Pic #1 is self explanatory.

      Pic #2 (a & b) likewise. Sorry they are bit out of focus.

      Once the motor block assembly has been removed refer to pic #3.

      Then proceed to pic #4.

      The RCS ELITE-3HV motor driver is mounted on a piece of thin styrene glued to the speaker magnet. I fabricated a pcb with a pair of reed relays operated by the RCS sound triggers to trigger the LGB sound. They are mounted on thin styrene on the lead weight just in front of the firebox moulding. The first installation had the RCS motor driver powering the LGB circuitry (including the inbuilt MTS decoder) via the disconnected track pick ups. The MTS decoder then powered the motor and sound just as though it was track powered. The performance left a lot to be desired. The loco was somewhat hesitant as though it had a bind and would slow down on curves. I was recently advised that any PWM motor driver MAY damage the MTS decoder so a redesign of the set up was in order. In the second version I bypassed the LGB circuitry and powered the LGB motor directly from the RCS ELITE-3HV motor driver. this increased the voltage going to the motor and any hesitancy disappeared. To maintain the proper function of the sound I designed and built an opto coupler controlled twin spdt relay switching circuit that turns the sound off when stationary and switches it on as soon as the motor driver output starts. The twin relays reverse the power going to the LGB system so that the proper 2 & 3 toot arrangement is maintained for forward and reverse. This arrangement means the LGB MTS decoder only ever sees smooth DC voltage from the batteries so cannot possibly be damaged by the PWM output of the motor driver. Although not shown the new pcb sits just in front of the RF-CHK pcb and ELITE-3HV motor driver above the metal sliding tray. The circuit will work with any brand of R/C system. If enough interest is shown I will make them available commercially.

      Pic #6 shows how the LGB ribbon cable sits above the motor driver pcb.

      I ran the battery power cable out the back of the space under the cab. Pic #7 does not show the RF-RX extension cable which also goes out through the same hole. I also mounted the three way DIP switch used for program changes in the same place.

      Originally I had mounted the RCS RF-RX in the boiler. However the range was not very good so I moved the RF-RX and AZARR antenna into the tender and mounted it under the coal load. I made up an extension lead for the loco to tender connection. The range has considerably improved. The two 7.2 volt 3,300 mah NiMH batery packs are mounted on ¼" square styrene tube glued to the floor with silicone adhesive. The battery packs are wired in series. They are then fed into a DPDT switch and 3 amp Polyswitch fuse for cisrcuit protection.

      Two small holes were drilled through the plate underneath the coal board front for the ON-OFF switch and outlet for the loco - tender wiring connectors along side the existing LGB plug and socket.

      Battery charging is via the jack mounted in the water filler hatch.

      I am not sure exactly how long the batteries will run the Mikado for but it is at least 2 hours. Plenty long enough for my customer. If anyone has questions regarding the installation please feel free to contact me off line. This installation feature was first published at LSC.
      ____________________________________

      Best wishes,
      Tony Walsham

      Remote Control Systems. www.rcs-rc.com/
        Modern technology. Old Fashioned reliability

    • February 11, 2006 6:13 PM EST

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      Tony
      As an ex professional electronic design engineer , I must tell you that your work looks very nice and tidy . Yes , I know it's your job , but a little constructive comment does no harm . Nicely done .
      Mike M
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