Recently, in one of our weekly Office Hours, we attempted to diagnose and repair a broken module that one of our students had accidentally fried. The Doepfer A-160 Clock Divider had been damaged after the system was turned on with the power cable connected in reverse, an all too common occurrence with some modules. While this was a great opportunity to review important safety procedures with our modules, I had a hunch that we might also be able to assess the issue, and possibly even repair it.
The student reported that the module had made a burning smell when the power had been turned on, so he quickly turned it off and adjusted the power cable fitting. Afterwards, the module powered on, but the only functioning output was the /2 division port and LED. The other division outputs were either malfunctioning or seemingly dead.
With electronics that are made of larger through-hole components like the A-160, fried components like burned resistors or blown capacitors are usually fairly easy to spot. An initial visual check showed no signs of obvious damage to any components on the board. It looked clean and new, despite the malfunctioning behavior of the module. It seemed that the only possible point of weakness that may not be obvious to the eye, was the integrated circuit upon which the module was based, the CD4024BE ripple-carry binary clock divider from Texas Instruments.
Locating a replacement chip online was easy, but I visited a local electronics store (support your local businesses!) and picked up a replacement chip made by Motorola for $2. At the following Office Hour, we popped the chip in place and powered it up, and to our shock and amazement, the module operated perfectly!
Of course, there is a lesson in this for all users, to double and triple check your power connections and when in doubt, do some research. The first (and hopefully most reliable) place to go would be the manufacturers website, where you might find the manual or specs for the module. Even an reference image of the back panel may tell you all you need to know. Another important reference will be the MuffWiggler forums, where other users may have discussed the same issues in the past. Chances are, if you are wondering, others have been there too. And don’t forget our omnipresent friend Google.
Have you ever fried a module? Tell us about it in the comments!