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Help needed with BLI Mikado headlight

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  • Member since
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  • 333 posts
Help needed with BLI Mikado headlight
Posted by jcopilot on Saturday, June 3, 2023 6:23 PM

Hi,

I have a BLI Mikado from the first run.  I replaced the QSI decoder with a Soundtraxx Tsunami2 TSU-2200 decoder - the one that's shrink-wrapped in purple vinyl and has all the wires.

The engine moves like it's supposed to, it makes the sounds it's supposed to, but the headlight won't work.

The engine and tender are connected by 6 wires with a harness at each end to serve as plugs into the sockets in the engine and tender.  I cut off one harness and spliced the Tsunami wires to the wires coming from the other harness.  I was able to trace the origin of each wire and I'm confident I've identified them correctly.  As I said, the engine moves and makes appropriate sounds.

The original headlight bulb had 2 wires, each one ended in a pin to be inserted into sockets behind the smokebox front.  The sockets are at the end of wires leading directly back to the PCB attached to the socket for connection to the tender.  The bulb was burned out, so I cut off the wires leaving the maximum length possible still attached to the pins.  I have been using a Miniatronics 12V, 30ma bulb as the replacement for the original.

Here are some test results:

There is electrical continuity from the plugs to the end of their wires.

There is continuity from the end of one bulb wire to the end of the other bulb wire. The bulb lights up when attached to a 9V battery.

My multimeter reads 12V when the probes make contact with the sockets - whether the headlight is turned on or off. I know when the headlight has been turned on by the sound of the dynamo.

When the plugs are inserted into the sockets, the multimeter, connected to the bare wire ends, shows 10.xxV with the headlight turned off and 9.xxV with the headlight turned on.

I twisted the wires from the new bulb to the wires with the plugs, inserted the plugs into the sockets and tested the voltage at the splice - .04V whether the headlight was turned on or off and the headlight does not come on.

Does anyone have any idea what could be wrong? 

One person said that BLI might have used 'half-way rectification', meaning the headlight could be drawing power from the frame.  I have tugged at the headlight wires and they run uninterrupted from the PCB to the sockets at the front of the smokebox, so there can be no connection to the frame.

Someone else suggested that somehow the headlight is drawing power from the track, perhaps a wiring mistake, as an explanation for the same voltage whether the headlight was turned on or off.  I've looked.  The decoder wires are spliced to the correct wires from the harness and I can't see any exposed wires that could be making contact with the frame or other wires.

I use Decoder Pro to program my decoders and the Tsunami2 offers a choice between incandescent bulbs and LEDs.  I checked and incandescent is selected.

So, what could be wrong?  The new bulb lights when connected to a 9V battery.  I get 12V at the sockets, but the voltage drops dramatically when the bulb is connected.  And I get the 12V whether the headlight is turned on or off.

I emailed BLI for help in spite of this statement on their website:  IF YOU HAVE AN OLD QSI EQUIPPED LOCO THAT WE PRODUCED FROM 2001~2007, PLEASE NOTE THAT WE NO LONGER ACCEPT THOSE FOR REPAIR OR PROVIDE SUPPORT FOR THEM.  BLI has not responded.  So much for their customer support.

Any ideas?  All help appreciated,

Jeff

If it's worth doing, it's worth doing twice.
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Posted by wrench567 on Saturday, June 3, 2023 7:15 PM

  What wires from the decoder did you hook to the bulb? Should be white and blue wire.

     Pete.

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Posted by woodone on Saturday, June 3, 2023 8:51 PM

Well it's time to get modern - change the bulb to an LED.

PICK up power from frame- use a 1K resistor on the power wire (the one from the frame) hook up to the LED and the other LED lead goes to the white wire from the decoder.

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Posted by jcopilot on Saturday, June 3, 2023 9:18 PM

Hi Pete,

Thanks for asking.  I've double-checked - yes, I have the blue and white wires spliced to the wires from the bulb.

Jeff

If it's worth doing, it's worth doing twice.
  • Member since
    December 2001
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Posted by mvlandsw on Sunday, June 4, 2023 6:36 PM

Does the Tsunami2 TSU-2200 decoder have built in resistors on the lighting outputs? Could the original headlight bulb been rated at less than 12 volts? 1.5 or 3 volts?

Mark

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Posted by ricktrains4824 on Friday, June 9, 2023 10:57 AM

The TSU-2200 should not have built-in resistors, but did you reuse the BLI light board? It might have included resistors on it...

 

Ricky W.

HO scale Proto-freelancer.

My Railroad rules:

1: It's my railroad, my rules.

2: It's for having fun and enjoyment.

3: Any objections, consult above rules.

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Posted by jcopilot on Thursday, June 15, 2023 9:57 AM

I don't know if the TSU-2200 has built-in resistors, I suspect not because there is 12 volts at the sockets.  And standard practice is to add a 1K resistor if using a LED with no exception for the TSU-2200.

Thanks for your input.

 

If it's worth doing, it's worth doing twice.
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Posted by jcopilot on Thursday, June 15, 2023 10:00 AM

My mikado did not have a light board.  There's a PCB right above the harness in the engine to connect the wires to the harness, but beyond that, the wires leading to the headlight are loose and free to move, there's no PCB between the harness connection and the headlight.

Thanks.

 

If it's worth doing, it's worth doing twice.
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Posted by NVSRR on Thursday, June 15, 2023 1:12 PM

I know you tested the bulb on a 9v battery.   Did you bulb directly to the new board to see if the board will power the bulb.    I'f it did. Then you could eliminate the bulb and board. And just look for a short. In the bli wiring Between the two.   To me it sounds like that might be where the issue is.   Some kind of frounding short allowing a constant voltage in. 

shane

A pessimist sees a dark tunnel

An optimist sees the light at the end of the tunnel

A realist sees a frieght train

An engineer sees three idiots standing on the tracks stairing blankly in space

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Posted by scott7891 on Friday, June 30, 2023 7:44 AM

jcopilot

I emailed BLI for help in spite of this statement on their website:  IF YOU HAVE AN OLD QSI EQUIPPED LOCO THAT WE PRODUCED FROM 2001~2007, PLEASE NOTE THAT WE NO LONGER ACCEPT THOSE FOR REPAIR OR PROVIDE SUPPORT FOR THEM.  BLI has not responded.  So much for their customer support.

 

Yeah, you self-owned from your own statement. 

You ignored their policy while on top of it expecting them to have knowledge about troubleshooting a new decoder that isn't even theirs to work with an almost 20 year old engine.  Their techs are only versed on THEIR products and current ones at that, not 3rd party products or BLI's own dated tech.  There is a reason warranties are limited to only their products and not others.  That would be like buying an aftermarket part for your car from 2007 then going to the dealer to troubleshoot a non-OEM part then getting mad when they can't help you because you brought them a part that isn't theirs to service that is on a vehicle way out of warranty.

You start messing with third-party products be prepared to fix things yourself.  Send it to a professional DCC Installer you would get more help from them.

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Posted by Tophias on Monday, July 3, 2023 8:48 AM

Did you try contacting Soundtrax?

Regards, Chris

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Posted by wjstix on Thursday, July 6, 2023 9:34 AM

jcopilot
And I get the 12V whether the headlight is turned on or off.

That's the odd part, it does sound like something isn't connected correctly. If you go back to the tender and take the blue and white wires and splice in a connection to the bulb - so it's connected directly from the decoder to the bulb - does it light up? If so, then maybe the harness connection isn't correct somehow. 

Some engines I've seen will run 12V wires to the headlight / number boards, but in the smokebox area have a small lightboard that reduces it to say 1.5V or 3V for low-powered light bulbs or LEDs. As someone suggested, it could be the bulb you're replacing wasn't a 12V bulb so that's why this one isn't lighting, but that doesn't explain why you're getting 12V readings at the final outputs - assuming that's where you're measuring.

CV61 controls headlight brightness, 0 to 255. Maybe check that?

Just as a "check everything", note as programmed at the factory, the decoder only will light the front headlight when the engine is set to go forward, it's out in reverse.

Stix

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