Digitrax DZ123MO older or new?

Last week I actually purchased my first DCC decoder from my LHS. I have a few MTL GP35's and wanted to start getting them DCC equipped.

The Digitrax DZ123MO decoder I purchased is that of a new batch as the LED is a white SMD. I recall the first batch of decoders utilyzed the T1 through-hole white LEDs.

For those of you Z scalers that have the MTL GP's and have purchased many of these DZ123MO's, what are your Pro's and Con's of these?

Does the older version provide a greater amount of light?

As I am new into DCC I greatly appreciate your inputs!!

Hobo Tim

 

You'll have to line the interior of the sheel with dark tape or the like as the LED lights up the entire shell. I used electrical tape and it worked OK.

 

i noticed in the newest GP35 release (penn central) they put black plastic inserts in the rear to avoid the lighting effect. they did this with the SOOs too, so mabey they're going to do it in all the GP35s from now on. i find this interesting, because the penn central shell is black to begin with, and i haven't observed any light bleed through on dark shells before.
dave f.

 

Tim,

The old boards put the light where it should be, close to the ends or light pipe locations. The new SMD LEDS are WAY back and produce much less light outut as seen from the outside. They also tend to create light bleed thru under the shell. While the old long T1 LEDs bleed thru a bit too, they were at the rear end or under the Cab roof (which had an additional black liner) so less noticeble.

There are two main issues tho: The LED location for installation and the board notches themselves. The older T1 LED is mounted on the top side of the baord and does not allow the cab shell to fit all the way down. You can grind the LED's right down to dang near the chip level but you still need to trim the Cab's black insert. The rear side is OK after filing. But most of us have simply turned the board over as it is symetrical. Unfortunately, this reverses the motor polarity (the DCC power feeds are "AC" so it doesn't mater). The fix is to change the CV for Normal Direction of Travel (NDOT) which is in most of the text step-by-step programming. But the LED's are not matched to that an you have to manually change their CV (F0F is now Reverse and F0R is now forward). Since you are new to DCC, that is a Function 'zero', not an 'oh'
The second issue is the mounting. The board notches are not in the proper locations. There are several comments about breaking this, filing that and board thickness. It is the same board thickness as the MTL board (an industry standard). The notches are in the wrong place. Some have made it easier by breaking off the front 5th tension post but the notches are still not correctly spaced. Breaking off the tensioning post could allow for the board to make it's way out of the posts or have intermittent contact, driving you more crazy. Simply fold the board on the side and reason where it would be if it was locked in place. File the two incorrect holes a bit more and it will more easily fit. NOTE: you can see the fine circuit board traces under the dark green solder mask. make sure you don't over file in that direction.
.

 

Hey Tim

Well its about time you got on the DCC band wagon!!!!!

Just kidding..... welcome aboard..

I have only had the older decoders (i bought a good supply a year ago), and use Jonh's (shamoo's) programing tricks and mine work great. He's got a list of the 5 or 6 CV's to adjust when putting the board in upside down that gets everthing perfect. You can program independent control of the front and rear light, so thet won't change over with the direction of travel, and can program MARs effects as well.

Hey John!!!!!! Hw about a little programing help for Mr. Tim!!!!

Tony B...
Wasatch Z Club

PS: If John won't post them, i'll dig them up out of my book and send then o you....