big boy 6-11436 issues 4005

The antenna is fairly easy, that is a JST-ZH 1.5mm 2-pin connector.  I have pre-made cables with those connectors.

Hard to say what is going on as far as your failure, but I'd start by unplugging the two smoke units from the RCMC as well as the two from the SFC board and running that way and see if any of the other stuff triggers the failure.  If that test is successful, carefully measure ALL the resistances of the smoke units, make sure there are no errant connections.  The smoke resistors should be around 8 ohms, and they must NOT connect to any of the other three leads on the smoke unit.  The thermistors should measure in the 45K to 60K range, they share a common with the smoke motor.  The smoke motors should run with 5VDC and draw an absolute maximum of around 50 milliamps.

@gunrunnerjohn posted:

The antenna is fairly easy, that is a JST-ZH 1.5mm 2-pin connector.  I have pre-made cables with those connectors.

Hard to say what is going on as far as your failure, but I'd start by unplugging the two smoke units from the RCMC as well as the two from the SFC board and running that way and see if any of the other stuff triggers the failure.  If that test is successful, carefully measure ALL the resistances of the smoke units, make sure there are no errant connections.  The smoke resistors should be around 8 ohms, and they must NOT connect to any of the other three leads on the smoke unit.  The thermistors should measure in the 45K to 60K range, they share a common with the smoke motor.  The smoke motors should run with 5VDC and draw an absolute maximum of around 50 milliamps.

as to measuring things I'm dumb as thumb tack on that part on how to do it and what is and or where is SFC board I know of 1 close to the whistle steam smoke unit but haven't a clue which connectors to unplug and there are 2 boards there an upper and a lower one

and are you saying you sell those antenna wires premade or just that you've made some for yourself?

and thanks for replying

Based on this being a "new" rcmc, I'd guess there was a reason for its replacement. Could you provide any back history?  Were there any flashing cab light codes?

Also, when using the MTH 4000, (it has a built in amp meter) did you notice any higher than normal amp draw while in various engine states?  I.e., smoke on, smoke off, whistle blowing, moving forward, etc.

It might be a pinched/crimped wire causing an issue.  I'd check the cables and see what you can see. It might not be a dead short, but I have seen where a small wire defect can cause issues like this.

As John mentioned, disconnecting the smoke units, might help narrow where the problem is.

Dave G

@gunrunnerjohn  okay I removed both smoke connectors at rcmc and the other 2 from am guessing the sfc board there are 2 boards right behind whistle smoke unit the lower board is where i removed the other 2 connectors ran engine for 20 minutes blowing horn all I wanted to and can change engine speeds as i wish no stopping or loss of commands from remote to engine and steam whistle never once cut out as a side note the metal bracket holding those 2 boards was lose as I could pivot it side to side so tightened it does it act as a ground by chance?

so do I now add one smoke unit only and see if that one creates my issues again or?

thanks for your help so far

Before adding any smoke units back into the mix, make SURE that all the wiring to those smoke units and the smoke units themselves don't have any pinched wires, shorted elements, cross connections between the fan & thermistor with the smoke resistors, etc.  The boards do not take kindly to any connections to the frame or having the unregulated heater voltage connected to the fan/thermistors.

@DaveGG posted:

Based on this being a "new" rcmc, I'd guess there was a reason for its replacement. Could you provide any back history?  Were there any flashing cab light codes?

Also, when using the MTH 4000, (it has a built in amp meter) did you notice any higher than normal amp draw while in various engine states?  I.e., smoke on, smoke off, whistle blowing, moving forward, etc.

It might be a pinched/crimped wire causing an issue.  I'd check the cables and see what you can see. It might not be a dead short, but I have seen where a small wire defect can cause issues like this.

As John mentioned, disconnecting the smoke units, might help narrow where the problem is.

Dave G

this makes the 4th rcmc replacement this engine eats them faster than smoke units eat up smoke fluid all 3 prior just stopped working period I was told to get some tvs? diodes and I did to see if electrical spikes are causing rcmc failures

I never looked to see what z4000 readings were at time of issues

I've checked for pinched broken wires found none other than the 2 antenna leads breaking away from solder joint to metal pins I have a love hate relationship with those antenna wires why they used aluminum looking wires I'll never know

see post to gunrunnerjohn above with smoke units disconnected issues all gone now to find the actual culprit or is it possibly the board itself seeing I'm not savvy other than checking track voltage using a voltmeter haven't a clue as to how or what settings on voltmeter to see if readings are correct for those connector pins etc

Here's a schematic of what a Legacy smoke unit with thermistor looks like, that should allow you to check and see if anything is amiss.

@gunrunnerjohn posted:

Here's a schematic of what a Legacy smoke unit with thermistor looks like, that should allow you to check and see if anything is amiss.

I haven't a clue as to how to use voltmeter to check if above schematic to see if readings are good bad or gremlins running amuck

as a update things went sideways after connecting any smoke unit's yesterday loss of control of engine again and the cab light no longer works! am thinking I can use a 1.5 aa battery to see if bulb is bad

so prior to that when I connected the blowdown smoke unit I got 8 cab light blinks in all this time never had that issue  did an engine reset cab lights still blinking  had to power it all off tried again same issue so removed connector at sfc board connected smoke whistle and got 6 cab light blinks meaning smoke whistle had issues again in all this time never had any of this happen until yesterday as for main dual smoke no cab light blinks so I walked away frustrated

today I powered it on tried a few different base to remote channels no help ran engine with only dual smoke connected used whistle sparingly and at 13 minutes kind of sort of lost engine control but if I advanced throttle knob to a  really fast speed I could gain control again unless I pushed the smoke whistle button and I noticed when this loss happens the red light on remote shines brightly so is it possible I'm really fighting a cab2 command base issue? I'm thinking of removing it and try using the tmcc cab1 and base to see if issues go away what's your thoughts on all of this?

I have both smoke whistle and blowdown disconnected so they play no part in todays gremlins  also when this loss of control from cab2 to engine transformer power does not increase or decrease and amps stay at 1.5 whether I have control or not

again thanks for your help gunrunnerjohn

@gunrunneerjohn all smoke units are functioning with an exception according to wiring schematic from lionels website for big boy whistle smoke connects to sfc at J6 and aux smoke to J5 so when I ask for whistle smoke I get blowdown smoke and if I ask for blowdown smoke I get whistle smoke!

so I thought okay maybe schematic for a newer version of big boy so switch smoke whistle to J5 etc and no smoke at all and  now I've lost capability of setting engine ID using remote when i push id number and set no whistle no nothing and if I hold startup or shutdown key on remote I no longer get voice commands to startup or see ya shutting down 

so is J5 actually the blowdown and J6 for whistle smoke I'm really confused with all these gremlins running amuck

It wouldn't surprise me if they had the smoke connections reversed.  Since you can pretty freely interchange any 5-pin Legacy smoke unit with another, no harm done, just plug them where they work right.   I routinely move a connection to see if it's the smoke unit or the RCMC/SFC that's the problem.

I can't say what is going on with your rig, the 2014 version of the VL-BB had a lot of moving parts!

@gunrunnerjohn PV you via email sent today

unsure what happened to engine now powers on when track power applied cannot program nothing best guess rcmc went poof or the antenna wires gave up

I did however fix the track signal issue seems one of the wires came loose from wire nut from command base so at least a win on that part

Any progress?  Good or bad?