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    Really dumb question about an Atlas controller

    I had a brand new Atlas controller switch bad right out of the package so don't assume the switch is ok.
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    Old School DC- blocks and 2 trains running at the same time- questions

    Even with two separate loops it would be a good idea to break up each loop into two blocks. That way you can move an entire train from one loop to the other. Park train 1 at the end of the block near the crossover, drive train 2 into the other half of the same loop, then flip the turnouts and...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    That was in the context of HO scale, where it appears a majority of HO modelers use DCC these days. I dabble in both DC/DCC. That 1400 appears to have about the same high/low amplitude ratio as other basic MRC power packs I've tested such as the tech4 200. They do it with a simple resistor...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    I'm just a self taught amateur so only sorta know what I'm doing. Still it's fun to learn how this stuff works, even if it's mostly obsolete in today's modeling world. The website that really helped me to understand how it works and what's actually happening in the circuit is the Falstad circuit...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    So I have found a simple way to make the acceleration and deceleration a linear slope instead of an exponential curve caused by the momentum resistor/capacitor. During accel the voltage is climbing quickly at lower voltages and it's difficult to adjust for minor low speed changes because the...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    Here are two waveforms with the same volt range and time scale. Both are running an Atlas/Kato loco at a scale 3mph. The pulse width of the ITTC is longer and flatter than the CC. The CC will make noise at 120hz, while the ITTC will be a lower pitch of 60hz, so the lower pitch is part of why it...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    It would be interesting if the reactive capacitor could be combined with the waveform of the ITTC 3000 throttle. Square PWM like the Varipulse throttle create alot of noise in the motor. The sine wave pulse of the CC creates some noise, not as bad as PWM, but still there. The ITTC uses a fixed...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    I power my test throttles with an MRC Twin Power Box transformer, 12vac and 18vac outputs, 65VA capacity and it has an internal circuit breaker. That PCB setup looks so cleanly setup.
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    So I think I'm starting to understand how that zener limiter bypass works. You mentioned a sting of diodes so I just chained a bunch together with a switch on the end. I simplified the right side to a freewheel diode, a 10ohm resistor and 10mh inductor to simulate a motor, with a 0.1 ohm "short"...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    I changed my schematic in Falstad to match the zener tapped after the 220R, but when I run the simulation using the dead short switch on the far right, the current through the load obviously goes to zero (left scope) but the current in the final transistor and the 1ohm (right scope) jumps way...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    This is the breadboarded circuit I'm using so far: I'm using just one 3904 as I read a report from someone who built several that the darlington paired 3904's would burn out. I only had 56K resistors on hand for high resistance areas, will need to get a variety of values to fine tune things...
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    Rich Weyand's CoolerCrawler analog throttle 2025 update

    Interesting to see that the old cooler crawler throttle is still popular. If I'm reading the PCB correctly you've made a few changes from the original. Notably some mosfets and the momentum cap looks to be 1/10th of the original, but I suppose that's due to the mosfet doesn't use hardly any...
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