Sunday, January 1, 2017

Designed to fail: AKG DPT-70

This is a bit of a rant post. Maybe I'll make a series.

Today's subject is an AKG DPT-70 digital wireless microphone transmitter. We have two of these, and a few months back, one of them was really quite loud and adjusting the level on the transmitter didn't do anything. It was clear that the connection between the outside control and the actual pot inside was broken.

Today I finally got the thing home and cracked it open.  Take a look at this.  If you wanted to design something to fail, this is how you'd do it.



A sturdy looking external control, linked to a pot inside via a 1.5mm plastic hex shaft.  Clearly these need to be treated very carefully to avoid snapping the shaft.

Since I can't effectively 3D print a 1.5mm hex shaft, I'm just going to leave the exterior control off so the pot inside can be accessed, and I will leave a tool to adjust it in the storage box. I found a bit in one of the cheap "precision screwdriver" sets I have lying around that fits (actually about 1.47mm, 1.5 is too tight) and printed a little knurled handle to fit it into permanently.