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Have a cab-1 that makes the beep sound when keys are pressed but will not respond to the command base. Have new batteries in there, cleaned the contacts on the board inside, all wires are soldered to where they should be.

When I press the keys to communicate with a TPC and/or rotate the red knob, no communication to the base or to the tpc. I even cleaned the inside of the crystal port and used a crystal from a working cab-1 and still nothing. It is not my power/tpc set up as it works with another cab-1 or cab-2. Had the antenna out and was next to the base. I have tried it all and narrowed down to a communication issue with the cab-1.

My question is... Is there a tuning knob inside the cab-1 like the one inside a command base? Wondering if that is the issue.

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So it used to work and now doesn't? As for tuning, although I don't know much about the CAB1, you would only need one side to tune to the other I would think. That sounds pretty far off to not work at all. A tuning issue would probably be iffy, not dead. So something pretty basic has happened to the CAB since another CAB works. Most likely the output fet or transistor.

A few side issues, so that in the future some poor soul does get confused.

- The Cab1 transmits to the Command Base, and there is no reverse communication. (The Command Base transmits to the track, and for at least TMCC, nothing replies).

- It is the red LED on the Command Base that blinks. The green is on when power is on. (Same for the next gen blue Base1L). I just tested both to make sure.

Correct Michael, I had the colors backwards, just actually looked at a TMCC command base.

The Cab1 transmits to the Command Base, and there is no reverse communication. (The Command Base transmits to the track, and for at least TMCC, nothing replies).

TMCC & Legacy are a one-way broadcast the locomotive never sends anything back directly.  The only way to get info from the locomotive is with the LCS system and the IR sensor tracks.

Last edited by gunrunnerjohn

John Will,

You actually made a mistake with green and red? Lol!
So, I did test it again and the red light blinks with a good cab-1 and nothing happens with the suspected bad one.

Someone suggested to make the crystals match up, they do. I swapped out the cab-1 crystal from another cab-1 that has become a parts candidate. I do have a few sets of alternate frequency crystals from the TMCC demo days when Chuck Hiram from Lionel gave me a few sets.

So, going to reopen this cab-1, clean the button contacts as most buttons beep but some do not.

So... give you an update on the cab-1. I just bought an original one in the white box and from what I see inside of it, the crystal socket is a white socket that hold the crystal. When I went to try it out, it would not respond to the base. All buttons work, just no base response.
First thing I did was look at the crystal socket as it is different with no plastic shelf underneath to keep it firmly in place. I bent the 2 pins slightly downward so they make contact with the metal tabs inside the socket. Works as if it was brand new which it is, just 25 years later, this cab-1 runs my trains!

I have another original cab-1 in the white box and when I opened it, the crystal socket is gray with a small shelf underneath so the crystal stays firmly in place.
I would think Lionel saw an issue there and replaced the original ones that had a white socket with a gray one and had an extra piece to hold the crystal in place.
This gets me thinking that the cab-1 that will not respond to the base could be not a broken trace but the crystal itself is not touching the metal tabs. Going to re-open that problematic one, bend the pins down a little and try it again.
P.S. I am not abandoning my cab-1s as they have been reliable now for 25 years but I do use a cab-2!!

Last edited by Ted Bertiger


So I was able to get this cab-1 red dial to work slightly as an engine would start off but that was it. With some heavy pressure on the knob, I was able to almost stop this engine. There is something obviously not sitting right with the 4 encoders. They are in there right, the small wheel is there with 1 set of encoder almost against it with the other set sitting a little farther. Can’t come to a conclusion.
Just might shelve both of them and as you said, they will become parts cab-1s.

If you get no response from the bad one, try the crystal from the good one.

I've used this on a few keypads, works like a champ.  KeyPad-Fix at Amazon.


I ordered this today from the bay for $5.99 plus shipping/tax. Do you put this on the rubber keypad or directly on the circuit board? I know you need to let it dry before using. I will be getting this in about a week.
Thanks, Ted

I have two CAB-1s that both do the same thing.  My layout is in an unheated garage (in California).  As the weather gets colder, the CAB-1s start working more and more poorly, until when they get down to about 60 degrees F they don't function at all.  If I leave them inside the house, so that they stay above about 65 degrees F, they work fine.

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