Lionmaster SD90 TMCC smoke problem

Without knowing the specific model, it's hard to be specific, Lionel has a number of smoke unit designs.

For common dumb smoke unit, the middle wire goes to frame common.  If you look at the PCB traces on top of the smoke unit, you'll see that it goes over to several of the mounting screws.  It's likely that it's already receiving it's ground through the smoke unit mounting bracket.

If it's something else, a model number and perhaps a picture of the top of the smoke unit would be useful.

Hi John,

Yes sorry that was dumb of me!  Its 6-28201 with one of the 610-4572-200 SQl/DSL/8 OHM smoke units.

Thanks

MIKE

I'm somewhat at a loss how it runs the fan in conventional and not in command.  I don't happen to have one of those here to look at, I don't remember how that particular smoke unit is wired. 

I think that one gets track voltage, heater voltage from the regulator, and common.  Track voltage feeds the fan regulator circuit.

Question, where do the two wires that are connected to?  Trace them out and see where they're connected.  I'm pretty sure one of the three wires is frame ground.

Thanks John,

I will investigate tomorrow -its early evening here and I am off to a meeting.

CHEERS MIKE

Mike,  I have that same smoke unit in a Lionel PA. The black wire on the 3 pin connector is  AC common from the regulator. On the PA, the fan motor receives power from a connecton to the motherboard. The heater resistor receives power from the AC regulator through the smoke on / off switch. If you have a voltmeter, measure the inputs to the smoke unit board. Accross pin #1 ( fan motor regulator, red wire  and pin #2 ( common, black wire  you should read about 13 vac. Accross pin # 3 (heater/resistor, other red wire  and pin # 2, you should read about 3.6 vac. Hope this helps.

That sounds about right.  Perhaps that wire broke off the smoke regulator, they are pretty tenuous there.

Mike here is a representative diagram for your unit.  This is based on the smoke unit not having any chips other than the diode and regulator to make DC for the fan.

If the unit was acting up before the wire came undone it may be the ACREG has gone bad.  I would make sure the (normally Brown) Serial data has a good connection to the mother board.

What you have is AC in Red for the heater and AC Ground for both heater and smoke fan DC power.  The 3rd wire is the AC in Red for the Fan DC Power.

Because the smoke unit only provides half sine wave to make DC power for the fan you may have an issue.

If you read your instructions there is some guidance on setting smoke levels.  So a reset may be in order.

I also have seen issues where a unit remembers the last TMCC Command when in conventional, until conventional power is cycled on and off again.  Hope this helps.   G

Hi John, GGG and lightningstrip. Thanks for all the advice. I took another look at the engine just now. I have found a second broken wire - again black but thicker gauge. It was covered with a piece of shrink wrap but had evidence of solder on it. It was lying on the chassis botton tucked under the bottom board.

So at the moment I am stumped. What I can say is it runs in TMCC with everything except the smoke fan. In conventional the fan definitely works and it smokes like mad - I tested it again after the comments! Weird - I wonder if someone has played around with the wiring to fix something for conventional running only - I have an email into the vendor to find out.

Living over here I take pot luck buying from the bay if the price is right and just occasionally it goes sour!

MIKE

Mike,

  Did you do a re-programming using Aux1 8

Bill

Hi Bill - Yes I did thanks. I am going to look again at the answers above and have another look later when hopefully I will have a bit of time.

AS always everyone - thanks for your interest in my train problems!

MIKE

Pictures would help at this point.  G

Hi G,

Since I last posted I decided to run the engine on a long test - this led to another problem appearing. The thing would just slow right down and then hesitate/move forward in short jerks.

I thought it was me so tried it several times over the weekend - same outcome. There were no flickering lights as in possible signal loss from the TMCC set up - so in the end decided to remove more of the internals to try and understand what was happening.

Short answer - in addition to the second exposed broken wire I mentioned earlier it looks as if the wiring has seen some work.After some experimentation I am now at  the position where with all the boards and plugs checked and secured the engine runs perfectly in TMCC with Odyssey off - I have no idea why I didnt thi k the switch position mattered.

I have also heard form the vendor who admits he bought it second hand  and only ever ran conventional.

So in conclusion someone has tinkered with all this presumably to get good conventional running. I freely admit my electrical knowledge is almost zero but at least I now have a great looking engine that now runs great in TMCC and for now I am going to live without smoke and accept the the vendors gesture to make the deal right.

Thanks for all your interest.

MIKE 

Sounds like ODY was causing some of the issues.  Have you checked the flywheel and tach.  Clean them if dusty.  G