Cruise M Help Needed

Classic case of the load on the serial data line causing the CC-M not to see the serial data.  I'll bet you're configured in TMCC mode, so it takes 4 clicks of he Legacy knob to get to the first speed step.  If you change it to CAB or R100, it'll take off with one notch.

This is the very reason I created my latest serial data buffer board.

R2LC Serial Data Buffer

John,

The CCM was in 100 step mode, but I was using a Cab1L so I guess that might make a difference on which step it took off on.

In any case the mod I made to power the CCM from the R2LC 5V supply worked well. It runs great. I used the ad-on 5V regulator to power the infrared tether. All the functions driven from the serial line are OK.

Here's speed step 1:

Two downsides:

The flickering firebox no longer flickers as the CCM outputs to the firebox LED module are configured for ditch lights so the LEDs alternately flash when the whistle is blown. I removed the wiring for the 4 that flashed. That left one LED on all the time.

The marker lights are barely illuminated. Very hard to see. Don't know why.

Ken

Ken, given that its working you are OK but know that Lionel uses the 5 volts from the R2LC to power the three wire tethers. They draw little current. I wouldn't swap them with your stand alone power at this point though.

Pete

Pete,

Thank you, that's good information to know for future installations.

What I don't understand is why Lionel needed to add the separate 5V supply. My older Mountain engine has the 5V from the R2LC powering the DCDR, tether, and 2 marker lights (through the DCDR). The Pacific had the separate 5V supply powering the DCDR, 2 markers, and the 5 LED flickering firebox cluster with the tether being powered by the R2LC 5V supply. Was the additional power requirements for the 5 LED cluster enough to overload the R2LC 5V power?

Ken

The R2LC has a TO-92 5V regulator, on a good day it will handle up to 40ma.  If you exceed that value, they will frequently overheat and either croak of just go into thermal limiting and fail to provide the required 5V.

Question: does pin 2 of the 10 pin connector on the Cruise M motor driver board feed the RS enough to carry it?  If not, how to feed it the RS board if the serial data buffer is not available?  Thanks; Falcon70

@Falcon70 posted:

Question: does pin 2 of the 10 pin connector on the Cruise M motor driver board feed the RS enough to carry it?  If not, how to feed it the RS board if the serial data buffer is not available?  Thanks; Falcon70

What engine is this? On most engines the R2LC serial data will drive a Cruise M and Railsounds directly. I have an engine where the serial data is driving two Cruise Ms and Railsounds. Serial data starts to have problems when it has to drive a two wire  IR LED or an AC Smoke regulator. 

Pin two is supposed to act as a serial data buffer but frankly its never worked that way for me. I have had to build my own buffer amps.

Pete

Pete; thanks much for the come back; I have adding Lionel DCDE cruise to MTH B units and its worked well; no RS at all; did an A unit with the DCDE and it did not play well with the RS; always came up conventional or no speed control.  As soon as I pulled the RS board, great speed control.  I need a serial buffer; will pick up some from GJ  when they show; how do you build a buffer?  Thanks for the info; Falcon

I'll be offering kits for the buffer soon, I just got all the parts in before I went on vacation.  When I get back next week, I'll post something.  As for the CC-M J4, pin-2, it can either have serial data or "duty cycle", that's a pulse that just says the locomotive is moving, it's designed for older diesel Railsounds boards to replace the axle cam or VCO.

Falcon, I have built buffers using darlington type transistors and well as single sided op amps much as John is doing. Since my parts stash literally goes back 50 years I use whatever is in the drawers. My op amps were made by Maxon. Probably won't help these days. John's solution is cheap and uses current production.

Pete

I was using transistors before, but I found that some of the issues with loading were amplitude issues, so I switched to the rail-to-rail op-amp solution with a 2x gain.  That seems to have been the "silver bullet" for the ones that didn't always work with the transistor buffer.

Thanks so much to both you wizards; will continue on the upgrades and wait for the Gun's buffers; sometimes quiet is good!  Falcon

So, given this information, what would have been the best modifications to make to persevere the original functions, not worrying too much about the cost?

Dave

I completed another ERR Cruise M upgrade using the same modifications as I did on the Pacific. This time its a Lionel JLC H7. Out of the box it performed OK, no Odyssey lurch, but I wanted to see if the slow speed performance could be improved.

Installed the Criuise M as per the ERR instructions and got the same runaway problem on the first few speed steps as the Pacific had. This engine also has the add-on 5V power supply powering the DCDR and later the Cruise M once its installed. Changed the wiring so the Cruise M got its 5V power from the R2LC. Powered the tether from the add-on supply and now slow speed performance is great. Speed step 1:

After making this change the marker lights were very dim so I changed their power source to the add-on supply with a 270 ohm resistor in series. Looks great. Another observation if you have this engine - the ashpan LEDs never worked. Discovered the factory had wired them backwards  . Reversed the wiring and they now work.

I'm not gong to say this is the solution for all Cruise M installations that suffer from runaway issues as I've only converted these two and might not do any more. The factory wiring for these two engines is pretty much identical so it might not work on another variation. But it worked on these two so I'm happy!

Ken

You have to be a bit careful not to overload the R2LC power supply, it powers the opto-couplers on the DCDS or CC-M, so any additional loads may push the little TO-92 regulator over the limit.

Agreed. I was concerned about how much the R2LC power supply could handle. Since the flickering firebox no longer flickered with the Cruise M, I disconnected 4 of the 5 firebox LEDs. On the H7 the markers are now powered from the add-on 5V supply as well as the tether. The only loads on the R2LC is the Cruise M itself , 1 firebox LED, and 2 ashpan LED's.

Ken

Depending on exactly how much current they're drawing, that could be a lot for the regulator to handle.  My experience with these regulators is around 40-45ma is all they can do without overheating.  They fail pretty regularly on TMCC smoke units driving just the smoke motor, very few of those motors draw more than 40ma.

Could be fine, just a heads-up on the limitations of that little part.

Great information. You're right, I could be on the edge of the regulator's capacity. I will watch it and if it fails then replace the R2LC and lighten the load on it.

I guess that explains the reason for the additional power supply.

Ken

Ken if the R2LC regulator fails, just replace it. No need to get a whole new board. $1.00 vs $40.00. Your choice.

Pete