Help with BLI MIkado

[jcopilot]

Hi,

I'm trying to replace the factory QSI decoder in my first-run BLI Mikado with a Soundtraxx steam decoder.  I found a Youtube video by Soundtraxx showing how to do it, but the decoder and wiring on their Mikado is much different from mine.

Their Mikado has 7 wires from the engine to the tender, mine has 6.

The headlight wires under the boiler are much longer than and allow the boiler to be kept away from the drive mechanism for easier access.  Mine has very short headlght wires and the boiler can hardly be separated from the drive mechanism.

The speaker in the video mentions testing the LED in the headlight, he uses a 9V battery with alligator clips and a 1K ohm resistor in line.  With that, his headlight lights up.  I can't tell if my Mikado has a LED or a bulb because it's hidden inside the smokebox and the wires get there thru a small hole in the bottom of the smokebox.  I can't see inside and can't access it to identify it or test for continuity.

Has anyone here opened a first-run BLI Mikado?  Do you know if the headlight is a LED or bulb?

One strange issue is that the wires from the headlight appear to join in a solder joint under the motor.  Can anyone verify that?  How does that work with either a LED or a bulb?

The wires from the engine to the tender have a plug at both ends.  I cut off the plug at the tender end to allow for soldering the Tsunami2 wires.  I've tried testing the headlight with a 9V battery with alligator clips and a 1K ohm resistor.  No light regardless of which battery lead I attach to which headlight wire.  Thinking it might be a bulb, I tested it with a 9V battery with alligator clips but no resistor.  Again, no light regardless of which battery lead is attached to which headlight wire.

I can identify the wires for the track power and the motor.  Out of 6 wires, that just leaves 2 so they must be the headlight wires, but the headlight doesn't light up regardless of how I test it.

Has anyone changed the decoder in a first-run BLI Mikado and can answer these questions?

Thank you for any help,

Jeff

[BigDaddy]

jcopilot

Thinking it might be a bulb, I tested it with a 9V battery with alligator clips but no resistor.

It should have lit with the resistor if it were an LED.  I would think a bulb, without the resistor should have lit, an LED would blow.

[gmpullman]

jcopilot

I can't see inside and can't access it to identify it or test for continuity.

It has been years since I installed a WOWsound decoder in one of my BLI 2-8-2s. I should still have the notes showing the wire assignments and I'll look later.

Have you tried to carefully pry off the smokebox front?

Mine was a Paragon2 (come to think of it, may have been a Blue Line I picked up for cheap) run so it has seven wires. The middle wire was for the chuff sensor IIRC. With the smokebox front off you have access to the LED and PC board and plug:

BLI_Mikado by Edmund, on Flickr

I'll take a look later to see what I did on the early Mikado back then. 
I didn't take that many photos of my decoder installs back then, either.

Good Luck, Ed

 

[Pruitt]

I have several of the original BLI Paragon Mikados. The headlight is a bulb, not an LED. You can very carefully pop off the smokebox front to access the headlight.

[jcopilot]

I didn't think of that - I'll try it.

Thanks.

[jcopilot]

I'll try that tomorrow.  Didn't think the smokebox front would come off.

[jcopilot]

To GMPullman and Pruitt - thanks very much for your suggestions.  You were right, the smokebox front is easily pried off and the light is completely accessible.

Thanks again,

Jeff