Replacement for MRC "Cab Control 55"

[nkalanaga]

Moderator:  This can be moved if desired.

My ancient MRC "Cab Control 55" handheld throttle died.  I have a spare, so am back in business, but does anyone make a similar throttle suitable for N scale?  MRC doesn't list them, or any other handheld DC throttles.

For those not familiar with it, it's an electronic DC, not DCC, speed control, that gets its power by wire from another AC or DC source.  The CC55 connects by a tether, with four wires, and has only the speed and direction controls, in a small metal box.  No momentum or braking effects, no meters, just a basic DC throttle.

My source is fine, so that's not an issue.  The power is getting into the CC55, so the wires are fine, but there's nothing coming out.

[peteski]

I saw your post about this in the Arnold thread.  Any way you could get a schematic diagram?  It should be an easy fix.  If this throttle needs external AC/DC power source that means it is just a fancy transistorized rheostat with a bridge rectifiier on the input.  Even though it supposed to have "electronic circuit breaker" the output power transistor is probably blown. Or possibly the bridge rectifier.

When you heard the pop, was there any foul smell (the type of smell when you let the smoke out of the electronic components)?

If it is simple enough, if you take close-up photos of the front and back of the circuit board, we should be able to "reverse engineer" it.

If you don't want to bother trying to repair it, try looking for these throttles on eBay. You might have to look for a while, but eventually someone will list one for sale.

[nkalanaga]

Thank you for the offer, but I doubt that it's worth fixing, cost-wise.  Schematics are out, as there's no documentation in the box, other than operating instructions. 

No, no smell, and after opening the case, no smell or visible damage.  I didn't try to take the circuit board out, so don't know what's on the other side.  I'll agree that it's probably a blown component, and some of the internal connections were still live when I tested them with a light bulb, so probably the transistor.  Wouldn't the rectifier be one of the first things power would go through?  I can't imagine how I could have overloaded it, as I've never managed to blow the breaker before.  My power supply is a Lionel HO power pack, rated for 1.25 amps and 16V AC, and the mechanical breaker blows on it before the MRC shuts down, even though its electronic breaker is only rated for 0.8 amps.   

I still have the Troller I repaired a while back, which had the bad pot, and another, heavier throttle that has an internal transformer, and may someday end up powering my coal company.  It doesn't have to be moved much, so wouldn't get tiresome carrying.  If I ever get around to finishing the cab-control wiring, the Troller will be the main standard gauge throttle, as it's rated for over an amp, and this one will go to either the narrow gauge or the MILW interchange.  Then I'll need the fourth throttle, although the MILW could be run from a fixed location.

I'll ask at the "local" hobby shop, which has a bunch of junk in the back, and they might have a similar throttle.  And, if all else fails, there's always eBay, but I'm not much for online shopping.

[mmagliaro]

These two places both make what appear to be nice DC throttles (probably better than what you had),
and they should function in place of what you had.  Caveat: I have never owned these.
I've only read reviews of them online, all of which have been good.

http://www.thegmlenterprises.com/id18.html

http://www3.sympatico.ca/kstapleton3/Index.html

[glakedylan]

in the past I bought dc transformers, power packs, whatever you wish to call them, just to salvage the speed control
then built my own in small plastic cases from Radio Shack, employing telephone wire/jacks to connect
fwiw

sincerely

[Ed Kapuscinski]

These were common in NTRAK layouts. I don't have a recommendation, but you might want to try looking for "NTRAK throttles".

[Rich_S]

Moderator:  This can be moved if desired.

My ancient MRC "Cab Control 55" handheld throttle died.  I have a spare, so am back in business, but does anyone make a similar throttle suitable for N scale?  MRC doesn't list them, or any other handheld DC throttles.

For those not familiar with it, it's an electronic DC, not DCC, speed control, that gets its power by wire from another AC or DC source.  The CC55 connects by a tether, with four wires, and has only the speed and direction controls, in a small metal box.  No momentum or braking effects, no meters, just a basic DC throttle.

My source is fine, so that's not an issue.  The power is getting into the CC55, so the wires are fine, but there's nothing coming out.

There is currently one for sale on eBay

http://www.ebay.com/itm/MRC-Cab-Control-55-DC-/261724522735?pt=Model_RR_Trains&hash=item3cefff48ef

[Sdynamo]

We've used these for DC control on our club layout and been happy with them:

http://www3.sympatico.ca/kstapleton3/851.HTM

[nkalanaga]

Rich S.  Thank you.  If the other hadn't mentioned the Sympatico throttles I might have bid on it. 

Max and Sdynamo:  Those look interesting.  The price isn't bad, although I wonder about shipping costs to the US, and the higher amperage would be very handy for my mainline.  I could use this and the Troller I have for my BN and narrow gauge, both of which use multiple units, and the spare MRC and ??? throttles for the MILW and coal company, which only need one unit at a time.  Thank you!

[mmagliaro]

You're very welcome.

I am afraid I don't have a lot of first-hand experience with throttles, as I have only
ever built all my own throttles.   It began as a teenager in the 70s, when I didn't have any money,
and I realized that by just scraping
old TV sets  for transistors, rectifiers, power cords, and other components, I could make a nice transistor throttle
for nothing!  The only money I had to lay out was for a case to build the thing in and maybe the knobs!

There are a great deal of really nice throttle circuit schematics online for free.  If you are reasonably handy with soldering up
a handful of components, even just using tag strips and point to point wiring (no etched PC board needed),
they are really easy to make.   That's just something else you might consider.

Good luck!

[nkalanaga]

I built one in electronics class in high school, so know that I can do it.  But building electronics has never been one of my favorite chores.  I took the class because they required a vocational class, then found out that my typing class also qualified. 

To this day I prefer mechanical to electronic devices for my railroad, and most of the "electronics" are relay-based.  Even my signal system, controlling the standard-narrow gauge junction and entry bridge, all in the same area, is all relays.  The bridge "detection circuit", showing whether it's closed and locked, is an old telephone relay, with multiple SPDT contacts, but no coil.  It's "thrown" by a slide-bolt gate/door latch, fitting into a hole in the benchwork, and pushing on the relay's "magnetic lever", while at the same time locking the gate in place.  The coil was recycled for wire years ago.  The rest of the circuits are DIP relays and DPDT slide switches, with one pole powering turnout frogs, and the other the relays.  Very much prototypical for the early 1970s, but not exactly state-of-the-art by today's standards!

That telephone relay is one of the few useful things I got from electronics class.  The teacher had a relay rack with a couple dozen relays, many with the connections damaged, that he was selling for a dollar or best offer.  I was the only taker, so got it.  A few actually work, but they run on 28V, so aren't much use to me.  The rest have a lot of very fine copper wire, and the contacts.

[randgust]

One of the reasons I still like DC as much as I do is the PSI 550 cabtroller; I think that throttle was probably as 'state of the art' in the DC world as I've ever seen.   The momentum and braking on it is just great (including something that works like a train brake handle), and there's something just cool about doing a brake set too hard and getting a penalty application - which it will do - and also that you can actually 'power brake' against the brake application with a throttle increase.    Having run actual locomotives I find this great fun.    I have yet to find a 'pushbutton' world throttle that is as much fun to use - shut off the throttle and coast - set up a brake application at the top of the hill and hope you got it right - bail off the brake and hit the throttle coming into the bowl and floor it headed back uphill....

I've had one of them since the late 70's and just picked up a second off of Ebay, they are pretty rare.   I've also got a couple home-brews that I made and the 'woodsman's axe' CAMA train controller basic transistor throttle.   But when you're cruising for old DC throttles, add that to your hunt list, I think you'd enjoy it.

[nkalanaga]

Everyone:  One of the members, who shall remain nameless because I don't know if he wants to be named, has graciously sold me an unused one at a very nice price - the postage.   I will certainly keep all of your suggestions in mind for when I need another, which I will, if the layout is ever fully wired...

[Freight Train]

I second Ken Stapleton's Varipulse controllers. Have used a pair he built for me in 2005 and they have worked faithfully for me since. They are transistorized with a variable momentum  you can set to your liking. He also at one time had these available in kit for at a lower cost you could build yourself. Been a while since I've been on his website so you might check out what he has to offer. Also had a pre-built circuit to control track side signals in conjunction with Kato turnout controllers.

[nkalanaga]

He still lists the kits.  The signal controller I don't know about, not having Kato turnouts OR much in the way of signals.  Mine are all controlled from the slide switches that work my turnouts, or from various other contacts, with relays to interlock some of them.  No detection circuits, or "block signals" as such, just junctions and the entrance bridge.

I'm still trying to figure out how the prototype would signal a standard/narrow gauge junction, with a "pointless switch", where both routes are available all the time.  Just don't try running a mixed-gauge train through it!  In my case the frog has to be switched to avoid shorts, so the signals indicate that, and only route is cleared at a time.