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Please Help, Identifying and resetting a decoder that is acting funny? MRH product support
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New member 5 posts Ernest E Pike New member 5 posts
Ernest E Pike

So, I have an Atlas U23b with an unknown decoder in it.
I tried to set CV 8 to 8, had no effect, except when I read CV 8 it is now 8, or whatever value I last entered, Also tried all the other reset procedures could find, none worked.
Other funny things:
The headlight and mute are mapped together, so turning on the headlight also mutes or unmutes the sound.
When setting the speed to 0 from a slow speed, the locomotive continues to move, independently of the momentum setting, as if it is on speed step 1.
There are no markings I can identify on the decoder, see pic with shrinkwrap removed, sorry for the massive size.
Any Clues?
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blindog10 Prolific poster 3,315 posts
blindog10

Early MRC?

And if it is, the reset is programming CV125 to 1.

The other reset method, preferred by many, is to unplug it and drop it in a trash can.   IMNSHO.

I still have one MRC decoder in an F-unit.  For a while it sat dead, ignoring all efforts to reset it, until one day I recalled that giving it pure DC could wake it up.  Touched a 9 volt battery to its wheels, and sure enough, it woke up.  Runs bad as new.  Stills sounds like a vacuum cleaner.

Scott Chatfield
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barr_ceo Super User 3,255 posts
barr_ceo

Is that green plastic in the

Is that green plastic in the background the original shrinkwrap?    Color can be a clue....

Read my Journal / Blog...

!BARR_LO.GIFFreelanced N scale Class Digitrax & JMRI

 NRail  T-Trak Standards  T-Trak Wiki   T-Trak Wiki Pages
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Nelsonb111563 Moderator 2,265 posts
Nelsonb111563

Looks like MRC decoder

Try setting CV125=1.  That is usually the reset for MRC.

Nelson Beaudry,  Principle/CEO

Kennebec, Penobscot and Northern RR Co.
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danw Active Member 49 posts
danw

Older MRC decoder

I have always heard the reset for an early MRC decoder is a swift blow with a hammer. Older MRC decoders are junk. I heard of someone several years ago now who was displaying his trains on a modular layout at a weekend train show got 8 plug-n-play MRC decoders before the show, so he put all 8 into his locos.

By the end of the show, all 8 of the MRC decoders had failed. Yep, the best reset is a swift blow with a hammer.

DAN WILSON
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Ernest E Pike New member 5 posts
Ernest E Pike

That is not the original SW,

That is not the original SW, but it is the same color as what was on it when I got it.
Also, looking at the way the leads are soldered does not look factory.

 
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marcfo68 Frequent poster 656 posts
marcfo68

. . .

.. That is the MRC factory look they hide under shrink wrap   : -)

This decoder matches the 0001626  and as per instruction sheet, no CV125 = 1 reset.  Do a Google on MRC 1626, nothing but problems.

Marc

 
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