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Looking for replacement rear wiring board / harness for MTH premier  rear passenger car . I have sent a couple requests to MTH but no response.

7A2FEF0D-7D7E-44AE-9078-7C855108301CInterior ceiling lights work ok , but rear marker lights ( three) are not working.

Any one know how to determine part number as I find MTH parts site difficult.

Would this part be available Elsewhere?

Any suggestions helpful.

allan.bisback@gmail.com

 

 

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Last edited by Al B
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I just happen to have mine apart for LED lighting of the overhead lights and passenger addition.  I’m planning to keep the incandescent lights for the marker lights and drumhead.  Didn’t realize that board had a bridge till I read your post and flipped it. Now, I just have to figure out the best way to wire in the LED regulator.  Maybe John will pipe in. 

Here’s a parts list/exploded view for an older set that I found using product search.  The chassis for recent releases is different, but the CV board appears to be the same.

https://mthtrains.com/sites/de...loded/20ps11086e.pdf

 And the part.

https://mthtrains.com/ag-0100010

The parts list says an exchange is required, but that’s not mentioned when you bring up the part.

IMG_4874

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Last edited by Lehigh74

All that's on that board is four diodes, seems pretty easy to troubleshoot.  I think maybe the bulbs are 3V bulbs and they route the power to the main lighting through that board and use the diode drops to supply the correct voltage to the bulbs.  I've tossed several of these putting in LED's, and that's the way they worked.

The extra 3V lighting is connected to be in parallel with the series diodes, they limit the voltage to around 3 volts.

I tried to decipher the board.  Not sure if I got it, but yep, the markers are in series with the overhead lights.  And the diodes aren’t a bridge, but are in parallel with the markers. 

So what led bulb should I get that I can stick in the hole where the marker lights are now?

Will these work?

GPW05W 50PCS Clear 4mm 12V 70mA Miniature Pre-Wired Grain of Wheat Bulbs Warm White for Model Train Layout or Architectural Project

Correct, the diodes are just a series string to generate a fixed 3 volts for the markers.

I would not use the ones you specify, 12V at 70ma is a pretty hot little bulb, and a 4mm bulb is doubtless too big for where the tiny bulbs are now.  I'd also be afraid of melting the shell with almost a watt of power dissipation right against the plastic.

What I do is dispense with all of those pieces and use LED's.  I wire them in series and tap them off the main LED strip with a series resistor.  The series resistor is tuned to adjust the brightness of the markers and drumhead LED's.  There is no danger of melting anything, and I can choose any size LED I need to get the job done.  Drumheads typically get flat surface mount LED's to give a wide light pattern for even lighting.

I’d like to get LED bulbs that I can sick in the existing holes.  Looks like the existing ones are 3mm diameter X 7mm long.  This one may work.  It also looks like it has the resistor prewired in and so could be wired in parallel.

https://www.amazon.com/dp/B07H...ref_=lv_ov_lig_dp_it

May also try the flat surface mount LED for the drumhead, but I don’t know where to look.

Do you have a PN or spec for the flat surface mount LED?  And for the resistor and 3mm LED if you don’t think the ones I linked will work?

3mm flangeless LED's are the ticket, that's what I use for many of these bulb replacement issues.  The Amazon ones are NOT flangeless.

Are you looking for white or red for the rear markers?  As for the SMT LED, you may have all you'll ever need if you've ever used LED strips, the 3528 LED is what I use for most of the drumhead applications.  Just take some off some unused chunks of the strips.

The markers are lanterns with red and green lenses so I’m looking for white LEDs.  The drumhead is on an open platform on a Madison car.  Not sure if I can make an LED from a strip work, but I’ll give it a try.

 I think I answered Al’s question about the CV board part number yesterday, but I also think I highjacked his thread.  I’m still not sure exactly what to get, but rather than continue to highjack the thread, I’ll see if I can find one where it’s been covered before.

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OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

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