Classic UK Minitrix Models  -  Class 47
Lower Board
I recommend that you don't do this unless you really really need to - perhaps because the green wire has become detached, for example.

The reason is that there are 4 tags to release and these stick up on thin plastic stalks.  The amount of movement to release the clips is greater than can be safely applied without permanently distorting the thin stalks.  This will prevent them springing back into place.  The reason that they do this is because the plastic is old.  There may be tricks that you can use to help - eg a little heat directed on the plastic with a hair drier, might make the plastic less prone to damage.  But I haven't tried this.  I just know that if you are not VERY careful, these clips will either bend permanently or break.

But if you must do it.  The cocktail stick is pointing at one of the clips. A little downward pressure on the plastic box below the clip will help it to pull away as soon as the clip is released.  Apply a little leverage to move the clip towards the centre of the loco.  Do the front clip (say) first on one side, then the front clip on the other side.  Once both front clips are out, you don't need to release the rear clips - the box will move back and drop out.
Here is the black box removed.  There is nothing there to service - apart from the soldered wire.  No need to clean it.  The contact arc made by the sweeping arm on the bogies is easily visible and can be rubbed gently with fine wet and dry emery paper without moving the box.  The circuit board simply lifts (or falls) off.  So if you break those plastic tags by removing the black box unnecessarily, you will have to find another way of holding your loco together.

Maintaining Classic UK Minitrix Locos
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