I have one of the original 120 ohm resistors, which came without the holes. It gives me excellent control of tjets and Tuff Ones (Aurora/JL/AW). A must get item, if you like the pancake motor cars.
If you get one, you want to apply some epoxy on the rounded side of the resistor. The flat side is what the wiper contacts, so leave that side alone. The epoxy reinforces the winds, so the resistor lasts longer.
Look inside the stock Tyco/Tomy controllers,usually the ohmage is stamped at the top end of the resistor,you can usually see the numbers if you look through the slots in the controller.
Some Tomy's are 45,some are 70 ,Tyco's usually are 70,both Tomy and Tyco 70's usually ohm out closer to 80 then 70.
2 part 5 minute epoxy is all i've ever used,i've seen them done with JB Weld,although i wouldn't reconmend it cause it will conduct electricity if you've mixed to much steel into the JB Weld
Thanks for the info on the epoxy. Has anyone on here tried the resistor mod using the two extra Radio Shack Resistors and a single pole double throw switch? I saw the write up on HO World looks like a cool and easy fix instead of having 2 or three different controllers.
I've used JB weld on controller resistors with no issues. 3 so far. Some epoxies can get soft and rubbery with increased temps. JB doesn't. It's not conductive enough to affect this sort of application.
I have also done the switch & resistor mod to a couple of Parma econo 90's and a turbo 45. Works great. I used a couple of 100 ohm 10 watt ceramics in series (200 ohm total) on the 90 ohm controllers for a final resistance of about 60 ohms when switched in, and used a single 100 ohm resistor on the 45 ohm controller for a final resistance of about 35 ohms. The change is a perfect step, not too much, not too little. I use the 90/60 controller on pancake cars, and the 45/35 on the inlines.
Don't go wild with the extra resistor because the resistance becomes non-linear in a big way if you are using supplemental resistors that approach the controller's original resistance. The supplemental resistor value should be about double the ohms of the original resistance. The resistor values are not *that* critical.
Some epoxies get rubbery,maybe,but i've done probably 50 resistors over the years and never had the 5 min stuff get rubbery.
Chuck the resistor in the oven for a few minutes to warm it up,then apply your epoxy or jb weld,they flow better when things are warm,try not to get to much flow over on the flat part of the resistor though
Kit bash stock Tyco 70 ohm/Tomy 45 ohm controllers for extra resistors,they work great on controllers from 35 ohms and down.
Manning's right on the resistor scenerio,get things to close together and the controller can get really weird on you.
Steve Medanic has a pretty good site on modifying resistor based Parma's