Saturday, 22 January 2011

Modding the Behringer - episode two

Welcome back. A quick update on the repair of the Behringer Ultracoustic ACX900:

One of the failed components on the Behringer was the switched 3-pole jack input on channel 2 which, being plastic, had sheared off at the base of the threaded bit. Our replacement (below) has a metal socket instead of a plastic one. Why this hadn't been fitted in the first place is a secret known only to Behringer. After all, channel 1 has a metal jack so why not channel 2?

Getting the old socket out was a nightmare. This is a double-sided circuit board with plated-through holes and lots of densely packed surface-mount components on the reverse (not visible here). The process of removing the old socket also removed some of the plating, so when we put the new socket in we weren't sure if there was anything left to solder the contacts to.
There are six miniature selector switches on this circuit board - four latched and two press-to-make. Two of these switches are shown below. Each switch is operated by a little button made of some kind of translucent plastic shit that fractures when you touch it (not a good quality in a button). Being custom-made to fit the Behringer console, these were not replaceable items (Maplin had never seen the like) and so we shored them up with glue from a hot-glue-gun. They won't fracture again, and they still transmit light from the indicator LEDs on the board. Bless the inventor of the hot-glue-gun. Get yours now and you will never regret it. A million uses.

The electronics sorted, the final step was to put the amp back together again. Below we are applying eff-off double-sided adhesive tape to secure the brown vinyl covering and to hide all evidence of our Great Hairy Leader's aggressive jigsaw-assisted entry. What you can't see in this pic is the wonderful new internal bracing behind the access panel, which is made of the finest seasoned Spanish oak, courtesy of Actreo Hardwoods (thanks Adam).

Rear view below. All done. You'd never guess we'd been in there, would you?

The moment of truth! We plugged it in and hired a crazy fiddler to take it through its paces. Sounds as good as new but we know it is technically sounder...

And finally - never a silver lining without diamonds falling out of his bum, our Great Hairy Leader made a beautiful bread board from the leftover Spanish oak.

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