WMD Pro Output Repair

I noticed that the nuts on the 1/4 inch TRS output jacks of my WMD Pro Output module were loose.  These get a lot of use, so I wanted to snug them up.  I am always careful not to over tighten nuts.  I used a 1/2 inch socket wrench and applied minimal torque.  The top one went fine, but when tightening the bottom one, it sheared off.

Side view

Shear point

I was surprised, because of the reputation of WMD for high quality components.  Notice in the side profile photo how these jacks have special lugs for PC board mounting.  The are standard sized TRS jacks and I happened to have some Switchcraft 112BX jacks on had.  The 112BX are similar to these jacks, except that they have solder lugs for panel mounting.  Whatever metal that was used for the barrel was very weak and could not stand any torquing down.

The Repair Job

I removed the front panel and disassembled the module.

To remove the three old jacks I first cut the pins going to the board.  I then removed the remains of the pins by heating and picking them out.  Finally, a solder sucker cleaned out the holes.  Now I had to figure a way to adapt the 112BX lugs to fit the board.  To do that I cut down their lugs to preserve the clearance between the panel and the board.  I soldered bus wire to each of the lugs.  Then I mounted the three jacks into the panel, tightening them snugly.

New jacks

In the panel

Then I reassembled the whole thing and soldered the wires.  There is a little skewing of the angle of the board, due to the wires not fitting perfectly.  I did not want to put bending forces on the board.

Final assembly

 

The module is again working, although I discovered a bit of intermittence on the right output.  Investigating that seemed to indicate it happened when the board was flexed, but the problem resolved itself.  Ironically, while doing this repair I realized that I probably do not need this module.  I can take outputs directly from the L-1 Stereo Output Mixer, either from its left and right outputs or from its headphone jack.  Those are unbalanced, but my cables are eight feet or shorter to the mixer.  Thus, I am considering removing the WMD Pro Output from the box to make room for 6 hp more of modules.

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