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This is a fine A-A set of Rock Island E8s issued in about 2000 I think and all the internal components are Lionel TMCC of that vintage. Everything works bar one thing, which is the motorized roof fans on the lead unit, which these E8s had instead of a smoke feature. The motor (which is larger than a conventional smoke unit fan motor) will spin when connected to a depleted 9 volt battery, but it seems it is not getting power from the board(s) it is connected to. 

I have traced the black pair of wires all the back from the fan motor PCB (MDK-039) to another component I don't recognize, which is the white board shown below and has a number of wires connected to it and a couple of caps. I can't detect any voltage from the two black wires when power is applied to the track but it's hard to get a reading with wires so small and bunched up. Everything else seems to work however. 

RockIsland_E8

On the other unit, the fans spin whenever there is power to the track so I assume the circuit is connected direct to track power. 

I've managed to track down a replacement MDK-039 PCB although not the white board, but wonder if there's a simpler solution, such as some TMCC off/on function. I got this set used and it did not include a manual. Any thoughts? 

Incidentally, the belt and pulley system K-Line used for this feature is superior to Lionel's later gearbox on the VL Centipede, which rattles like there's no tomorrow - both are shown below:

RoofFanDrives

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@Norton posted:

Get a closer look at the board that powers the fan unit. If it has a regulator on it you can tell what voltage the fan motor runs at. Optionally measure the voltage on the fan motor that works. Easy to make another regulator board or use one of those buck/boost board off the internet.

Pete

This is what's on the Fan Motor PCB:

MDK-039

To be brutally honest I would not know a regulator from a schmegulator but I'll extract the motor from the mount it's in and see if I can read any voltage info from that. Fortunately I do know about buck/boost boards and have some spare adjustable voltage AC-DC converters small enough to fit in the body shell. I think you are saying use that to power the fan from track power, right? It doesn't matter to me if the fans spin whenever there is power to the track (although I had wondered about wiring them to one of the can motors so they only operate when the engine is moving).

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  • MDK-039
@Norton posted:

Can you read what is on those black devices to the right and foreground in your picture? 

Pete

Two of them have this printed on them: 2N 3904 - 006. The third to the left appears to have this: 7 MPS A14. That one is in the space marked on the board as Q3; the others are are in spaces Q1 and Q2. 

I assume that this is some kind of constant voltage board. Possibly dumb question but what happens if I connect this to track power?

P.S. Motor is a Mabuchi but no serial number or other ID on it:

Mabuchi

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Last edited by Hancock52

If the white coonector goes to the motor which I think it does then you should be able to connect to two black wires to a transformer, then monitor the voltage at the two pins in the white connector. That will verify if the board is bad or the motor is stuck, not uncommon. If you get nothing from the white connector then you will want to measure the voltage on the other board that works to determine what to use as a replacement.

Pete

Do NOT connect the motor to track power.  Since there is no smoke, I'd control the fans with the smoke output.  A simple DC power supply there will do the trick.  I'd probably use a variable power supply so you could adjust the speed of the fans.

John, meanwhile I have sent you an email on variable voltage AC-DC power supply boards you've supplied for me in the past. 

I'll have to hunt around for the smoke supply on the control boards but I think the problem is that there's no power coming from that source in the front unit, for whatever reason. (I haven't tried toggling the TMCC smoke control on/off but will do so.) I think I have worked out that the motor is only a 3VDC model. 

I am guessing they didn't use a common three terminal regulator is because they run that motor below 5 volts though they could have used another type of adjustible three terminal regulator. The roof fans turn at very slow speed even with the reduction provided by the pulleys. If we knew what the voltage coming out of that board is we could better provide options. 5v from the smoke fan may be too high or they could have used a 24 volt motor driven at 5v???

Pete

Last edited by Norton
@Norton posted:

I am guessing they didn't use a common three terminal regulator is because they run that motor below 5 volts though they could have used another type of adjustible three terminal regulator. The roof fans turn at very slow speed even with the reduction provided by the pulleys. If we knew what the voltage coming out of that board is we could better provide options. 5v from the smoke fan may be too high or they could have used a 24 volt motor driven at 5v???

Well, since it's a 3V motor, I suspect around 3V.    I wonder how much current it draws...

@Hancock52 posted:

 I think I have worked out that the motor is only a 3VDC model. 

 

 

Right, many thanks to both Pete and John for the insights. The good news is that the fan motor and the MDK-039 PCB it's directly attached to are both functional. The fault, whatever the cause, is that there's no power from the connection at the white board near the motherboard. I tried Pete's test powering the lead unit PCB from the transformer and that runs the fans.

Power output at both the lead and trailing units' PCBs measures slightly more than 4 VDC and the fans don't spin at breakneck speed. Toggling the smoke unit on/off keys (and a soft reset) has no effect on either unit although it makes sense to me as John suggested that the smoke outputs would have been repurposed for the fan motors. I have not tracked down K-Line diesel reset codes so I have not tried doing that. P.S. Even with a Legacy command base connected, the fan speed varies with transformer lever movement so I guess that it might not be command controlled at all. 

So, as the PCBs appear to be OK, and unless this might cause another issue, I'll wire the lead unit PCB to track power. I really don't know how the PCB is feeding DC to the fan motor as there's no rectifier on that board (but there are several diodes on it, which I'm guessing have the same purpose). 

Just as a matter of interest, opening up the trailing unit shows a set of electronics that I don't think I seen before (but I am no expert), especially the big blue caps. There is a tether between the units so I guess that this is a slave board arrangement of some kind:

E8s_Rear_Unit

Many thanks again.

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Last edited by Hancock52

Pretty sure the roof fans just go to track power, they are not controlled remotely. There might be switch to turn them off but not sure of that. My E8 is buried right now. The E8 motors are all driven by a single motor driver in the lead engine. I think the caps are there just to smooth out the power to the trailing engine.

I ended up putting a Cruise M in each engine driven by a single R2LC. Required new tethers though for the added wires required.

Pete

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