Athearn has a PC board that it had included in some of the newer, non-ex-bluebox RTR locos. This has become available as part 90616, and it makes installing DCC in bluebox or RTR GP38-2s and GP40-2s a lot easier -- there are positive solder points, both an 8-pin and 9-pin socket, and the option of adding 1.5 v bulbs. The most recent run of GP38-2s has this board as stock, which makes these as easy to convert to DCC as any other Athearn RTR.

Here is a board installed, as yet without decoder, in an older RTR GP38-2 chassis:

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As is, this makes a DCC conversion a little easier, because it allows you to install the 90616 board and do the rewiring needed, but then test that install under DC, so you eliminate any debugging issues during the install where a wiring error might be the problem, rather than the decoder.

Here is a GP38-2 chassis with 90616 with a Digitrax DH126:

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However, I found that when you add an older RTR GP38-2 body, the 90616 doesn't quite fit. I had to hog out a rebate in the shell roof weight retainer to clear the 8-pin socket:

[attachment=19177]

For some reason, this isn't a problem in the latest-run GP38-2s with the 90616 installed. I also discovered that you have to be careful how you install the shell with a larger decoder like the DH126. I used Scotch Magic Tape to hold the decoder in a more positive position so it wouldn't catch on the shell:

[attachment=19176]

Here's the finished project:

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One thing I would suggest, as is also typically suggested when hardwiring a decoder the old way - that front light bracket isn't the most reliable source for pickup from the chassis. The couple of old BB locos I have, that piece is loosely riveted to the chassis and moves around quite a bit. A better way to get power from that side of the pickups is to drill a small hole and use a brass screw, then solder to the screwhead. BEST is to go right to the brash bushings - I have 2 RTR RS-3s (that already have the circuit board) and one was intermittent even after I soldered a wire to the metal sides of the truck frames. Wipers on the bushings is my next step with that one, in the meantime I got the second one and it worked fine out of the box!

--Randy

I agree and have done the screw on other conversions. Depends on whether my tap drill is either too dull or broken!

I've eliminated the frame ground altogether....


I've soldered track power wires right to the brass rivets on each truck axle plate.
ALL my BB locos run flawlessly w/DCC!