The is a drop-in Rectify speaker for all Atlas EMD AEM-7 locomotives.
 
How the speaker installs depends on which production-version of AEM-7 you have.
 
For early, 8-pin Classic models, the speaker installs in the roof-top resistor-pack detail. Simply pop the top casting off by pressing the four pins inside the shell. Solder wires to the speaker, press the speaker into the resistor-pack casting, feed the wires through the hole and snap the casting back onto the roof.
 
You can then either use a small 8-pin decoder plugged into the stock motherboard (if you can find room to place the decoder) or replace the stock board with a Nix Trainz Decoder Buddy and 21pin decoder.
 
For current-production Master models with the 21-pin board, the first speaker can be installed under the PCB (where the stock speaker resides) using short wires. A second speaker can be installed in the resistor-pack just like the Classic model noted above for a dual-speaker installation. The third set of photos show basic installation procedures.
 
The speaker comes fully assembled and tested.
 
Dimensions: 6mmH x 19mmW x 23mmL