# Bachmann K-27 with Turbo Smoke questions



## jimtyp (Jan 2, 2008)

I'm installing a Turbo Smoke Unit in my B' K-27. The unit I have requires about 18v to put out good smoke. So I don't think I can use the old smoke unit wires? I assume the input wires to the original unit would be something more like 5v? I think I need to go directly to the left and right rail pickups in the loco?


Also, for the chuff part of the turbo smoke to work I need a ground. Any suggestions on what I could use as a ground in the loco (not the tender)? 


After I get this thing working I'll post some pics/video and how-to for anyone interested.


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## StanleyAmes (Jan 3, 2008)

Jim

On the main board at the top of the boiler rear are the locomotives raw DC + and - . This raw voltage is also abailable on the lower board that has the connection to the motor. This raw + and - come from whatever you have in the socket in the tender. SInce you are using track powered DCC this voltage is about 2 volts less then the DCC track voltage.

The control wire for the smoke unit comes from the tender and goes directly to the main board in the boiler.

If you need raw track power the best place to tap into it is on the lower board near the motor. Not sure where the voltage regulator is for the smole unit but I believe it is on the main board so I do believe the two wires going to it are indeed low voltage wires.

Hope that helps.

Stan


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## jimtyp (Jan 2, 2008)

Thanks Stan! What could I use for ground?


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## Greg Elmassian (Jan 3, 2008)

Is this the TAS unit? If so, you want to ground the chuff wire instead of having it chuff? 

Just curious, Greg


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## StanleyAmes (Jan 3, 2008)

Jim 

The locomotive DC- is the locomotive ground. I do not have experience with the specific chuff unit you wish to install. I believe others such as Greg have some experience with this smoke unit and can help you with which wire on the smoke unit is the raw voltage wires and which is the controll wire and which is used to trigger its chuffs. 

Stan


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## jimtyp (Jan 2, 2008)

Greg, yes, this is the TAS unit. For the smoke to work with the chuff I need a ground and a trigger. I was going to use either the optical sensor or magnet for the chuff input but also need a ground. 

Stan, which pin is the DC- in the loco? Should i use the pin marked M- (Motor negative)?


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## Greg Elmassian (Jan 3, 2008)

Jim... I ordered mine "for DCC"... it came with a full wave bridge, so I can hook it right to the rails... your "ground" would be the minus side of the FW bridge. 

The chuff wire just needs to be grounded to "chuff". 

I would use a magnet for the chuff, interfacing to the original circuitry might make you crazy. 

Regards, Greg


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## jimtyp (Jan 2, 2008)

Greg, yes mine came with the bridge also for DCC. Okay, for power I'll hook it directly to the rails. Got that done. 

Using the optical sensor for the chuff input might make me crazy but I'd like to try it first  With the boiler off I found the wires that provide the chuff from the optical sensors using a meter - one is blue the other is orange. If I hook up these two wires to the input chuff for the TAS, do you think that will work or cause problems? I may have to invert the signal with a NPN transistor just like I have to with the chuff input to the Phoenix P5. If it will work the other thing I need is a ground wire in the boiler.


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## Greg Elmassian (Jan 3, 2008)

I need to look at the K schematic again... how about you do the legwork and post the link? I'll look at the circuit. One problem with the circuit if I remember correctly is that it did not get all the way to ground, another problem is that it's powered from a different circuit, may have ground level problems, and also you will probably have to invert the signal... other than that it will probably be a piece of cake... 

Do you get my comment about going crazy? 

Anyway, find the link, and we can all hack at it... 

Regards, Greg


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## StanleyAmes (Jan 3, 2008)

Jim 

Forget about the schemantics and unless you are good with electronics do not connect directly to the optos. On the chuff circuit board on the cab end of the motor there are two diodes just before the wires going to the tender. Connect on the side of the diode that goes to the wires going to the tender. Simply use the transistor inversion approach you used in the tender connected the same way as you did to your P5 

If you want the smoke to be 2 smokes per revolution use one sensor. If you want 4 chuffs per revolution use both sensors. 

Do not connect anything to the motor wires use the wires labeled + and - which are J1-7 which is the - or ground and J1-6 is the raw + or positive. The rectifier is already there for you to use. 

All the connections you need are on that lower board which is easy to get to. 

Stan 

Stan


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## Greg Elmassian (Jan 3, 2008)

Stan, I think you are overlooking some of the things I mentioned. But, go for it, if it does not work, then you can explain the differences in the ground potentials. 

Jim, I gave you my best recommendation, use a magnet and pickup... if you want to use the existing chuff circuitry, I think some more investigation is in order. 

Since Stan has chosen say "forget about the schematics" obviously he knows exactly how to make it work. If you follow Stan's advice, please be sure to ask Stan if you have problems. 

Regards, Greg 

(Stan, it was ME that was going to look at the schematics, and I AM good with electronics, and the implied insult is registered, but just go ahead and make it work for Jim, that's all that counts)


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## StanleyAmes (Jan 3, 2008)

Greg

No insult intended. Poor writing on my part. While you can look at scemantics I do not believe from talking that Jim understands them. From your notes I was underthe impression he needs an 18 volt +, a Ground. and a ground trigger.

The connections on the lower board are exactely the same as the connections in the tender. I use these connections for adding things to the locomotive since they are so easy to get at.

The ground potential should be the same if these connections are used.

Stan


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## jimtyp (Jan 2, 2008)

Greg, these are the schematics that Bob Grosh put together for the K-27: 

 Wiring 

 Interconnection  

Yes, it may make me crazy and harder than just magnets, but if I switch to magents I'd need to convert the P5 to use magnets also as I would like to have the puff and chuff in sync. Hopefully I can learn some electronics from this also 

Where is Bob these days anyways?


Stan,


I have 2 wires left to hook up for the smoke unit. These are the ones that give it the puff and chuff. If I hook up these wires to a reed switch (one wire to each end) and run that over a magnet I get the puff in sync - pretty cool. Now I just need to do the same with the trigger from the optical sensor triggers. So I'm not sure if I need ground or common + to complete the circuit when the optical sensor fires?

Also, you are saying to use the connections on the board marked PCB08 in Bob's Interconnection diagram? I don't see a diode, do I need to look at the underside of the board?


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## Trains West (Oct 4, 2008)

what is wrong with hooking it to the chuff on pin five of the board ?

I did a 2k2 board to this pin and it worked great .........


it is just a ground like a reed switch


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## jimtyp (Jan 2, 2008)

Scott, I have done this also for the P5, it does work great. However, I was looking for something in the boiler because that is where I have the smoke unit, and I didn't want to run another wire from the loco to tender.


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## Trains West (Oct 4, 2008)

why would you have to run them back they are there now ...

if you look on pcb05 board the orange and blue are chuff 1 and 2 you can tap into either one all of the electronics should be on the pcb08 boards .......


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## Greg Elmassian (Jan 3, 2008)

It think Scott has it right, although the jumper to connect the 2 chuffs is on the tender board I think. If it is in place, I think you can use either board. 

But the chuff outputs are positive going, and the chuff input on the TAS is negative going, so that's where you need the transistor to "invert" the chuff signal. 

Otherwise, the smoke unit may run all the time, and only "stop" when you actually want a chuff. 

Regards, Greg


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## jimtyp (Jan 2, 2008)

Thanks Stan, Greg and Scott!! It's working  I'll post a review of my findings in the Product Review. The puff and chuff is pretty cool, and this unit does put out a fair amount of smoke. My wife came down to the basement from upstairs and said she could smell the Yack fat candle I was burning all the way upstairs and was afraid I was going to set the smoke alarm off  

I ended up using the optical sensor. I didn't connect directly to the chuff trigger, which is marked "A" on optical sensor connection on PCB05, but followed the circuit and connected into it after the diode that Stan suggested. Because I needed to invert the signal I set up the same PNP transistor that I have in the tender for the input into the P5. For a ground I used the optical sensor "B" connection on PCB05. 

The puff and chuff are now in sync! Going to make for some cool slow start videos


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