Does your Athearn F7A 1973 make a grinding noise during turns?

Discussion in 'HO Scale Model Trains' started by mikebalcos, Jul 11, 2007.

  1. mikebalcos

    mikebalcos Member

  2. YmeBP

    YmeBP Member

  3. doctorwayne

    doctorwayne Active Member

    It looks to me as if these two locos are the same. Run your loco around that 18" curve with the body shell removed, and look for a possible source for the grinding noise. My guess is that one of the metal straps that stick up from each truck is rubbing on the flywheel when the trucks pivot on the sharp curve. The metal strap system is not the best way to get the power from the track to the motor, and is best replaced with wires soldered between the trucks and the motor. I'd offer a picture on how-to-do it, but all of my Athearn diesels have been remotored. ;-)

  4. nachoman

    nachoman Guest

    could be just a bad universal joint...

  5. YmeBP

    YmeBP Member

    I put a dcc decoder in mine and i soldered up the wires as you mention here. I think i've run it w/o dcc 1 time and i use 18" turns too.
  6. doctorwayne

    doctorwayne Active Member

    As I mentioned previously, my Athearn switchers have all been remotored. However, the modifications to the trucks are the same, so here are some pictures to clarify things. (Hopefully! :rolleyes: )

    This is an Athearn switcher: you can see how the strap that sticks up from the truck has been cut down - this eliminates any chance that part of it will inadvertently rub on the motor, flywheels (mine have been removed), or inside of the bodyshell. On this loco, it also helps to avoid contact with the lead weights that are secured to the inside of the bodyshell.

    Here's a view with the driveshaft removed: the black wire is soldered to the stub of the former strap, while the red wire is soldered to the other, normally unseen contact strap. The truck retaining set-up is a bit different on these switchers than that used on the geeps, but the main thing to remember is to keep the solder build-up and the wire away from the area around the hole in the strap that the nub on the frame seats into.

    Another view of the wire connections. Here, and in the shot above, you can see the rust on the flat strap to which the red wire is soldered, one of the reasons why the strap system is not very reliable.

    The set-up with the circuit board, rail joiners and bits of rail soldered to the ends of the wires was installed to permit easy change-out of the trucks or motor, without having to unsolder anything, and was installed before the current trucks were acquired. This would probably make it easy to convert these locos to DCC, too, although that is not my intention.

    On a loco with its original motor, the red wire (from both trucks) would connect to the copper strip on the bottom of the motor. To make this connection, it's best to remove the motor from the frame, then remove the copper strip from the motor: it simply pries off, but be careful, as it retains a spring which holds the lower motor brush in place - don't lose either! The black wires connect to the top copper strip on the motor - remove and discard the long steel strap, which will reveal the copper strip. Remove it as you did the bottom one - careful with the spring and brush on this one too! Removing these copper strips before soldering avoids heat damage to the motor, springs, and brushes and also makes soldering easier, as there's nothing else to heat except the strips.

    Hope this will help to improve the performance of your Athearn locos.

  7. YmeBP

    YmeBP Member

    This is awesome!! :eek: especially the joiner and rails!

  8. jeffrey-wimberl

    jeffrey-wimberl Active Member

    Ah yes. The v enerable Athearn F7! I have quite a few of these beasts, eight to be exact. I've only had two that made the grinding in the turns that you mention. One was a case of a pickup strap rubbing against a flywheel. I simply bent it back into shape and the problem was solved. The other was a little more involved. It involved one of the gears in the forward gear tower. The lubrication hadn't been sufficient and one of the gears was wearing down. The noise was being made by the teeth failing to mesh properly. In a turn, the gear would be pushed to one side and the teeth would start slipping against each other. I replaced the gear with a new one and made sure the gears were properly lubed. It's run very well ever since. That was three years ago. The loco was bought in Leesville in the early to mid 80's.

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