It's probably not worth trying to repair a DH121 because replacements are so inexpensive.  It should be very easy to replace because the DH-121 decoders have a 'standard' 9-pin socket (not a NMRA 8 pin socket, but Digitrax standardized on these and IIRC TCS also uses them).  You should be able to unplug the bad decoder from the wire harness, and plug in a new decoder.  And new decoders probably use less space than a DH121 too!

Charlie

Yes, there are more modern and smaller decoders with the 9 pin JST connector. NCE and Digitrax have them. No doubt some others.

Go to the Litchfield site and look around. There are good descriptions of what exactly you will get. A little home work will go a long way.

Search Google for Litchfield Station DCC. I rather not post links to companies here. Save the links to Favorites for future use and to give to others.

Rich

Search Google for Litchfield Station DCC. I rather not post links to companies here. Save the links to Favorites for future use and to give to others.

Rich

It's never a problem to post a link to a company website here.  In the case of Litchfield Station, they are a sponsoring advertiser so their link is available on the MRH sponsors page and I've linked it here as well.

Ok, did not know and did not take time to look around for the posting of companies issue.

Some forums are run by people with tender sensibilities. Just trying to be careful.

Litchfield has been my DCC supplier of choice for over three years. The new owners are continuing just fine. I just received a new order of decoders and speakers.

Rich

I just noticed this question at the top.

"I have an older DH121 Digitrax decoder that the headlight circuit no longer works.  Is it possible it has a bad diode that can be replaced?"

What makes you think there is a bad diode? Since you sound like you are aware of the electronics invloved, you might be interested in the below comment.

You could even use the rear light option if the headlight circuit no longer works.

Did you try to reset the decoder to factory specs?

Just cause I can, I removed the shrink, unsoldered the 9 pin JST connector on this type of decoder and soldered in #30 NMRA colored wires for a more compact install in an older MDC Boxcab track cleaner for our club layout. Runs the open frame motor just fine pulling a John Allen boxcar with Masonite slider.

Your mileage may vary.

Rich

Ok, did not know and did not take time to look around for the posting of companies issue.

As long as your not advertising your company or trying to sell something it's usually fine.  When discussions turn to money changing hands, that's when the folks at MRH deserve to get a piece of the pie.  Otherwise it's usually OK!  Not too much moderation here at MRH as long as we remain somewhat on topic and keep it rated E for everyone. [smile]

Litchfield is a quality supplier.  I don't see that changing too much under the new ownership.

I would like to replace the docoder with a TCS decoder.   I could use more than one.   Is there a place where I

could order four or five inexpensively.

At least two of MRH's sponsoring advertisers sell decoders.

• Tony's Train Exchange
• Litchfield Station

At the top of this page there is a row of 'tabs':

Home - News/Events - Sponsoring Advertisers - ...

Click the 'Sponsoring Advertisers' tab. Then click the logo for Tony's or Litchfield to get to their websites.

Cheers,

Charlie Comstock

Litchfield has free shipping if over $75.00 and good prices for shipping even under $75.00. That has been my experiences for three years. Very prompt delivery also. They are in Arizona and I am in western Mass.

Rich

Hey mrich

I was going through stuff I forgot about after a move some years ago and found some unused decoders. Two are the DH121 Digitrax decoder still in package. Contact me off the list if interested. I have no use for them.

Rich