Arturia microFreak
This is the first Arturia in my workshop. As a rule, I don’t take on repairs of instruments from this company, or others for which schematics are nowhere to be found online, because repairing a device without a schematic is a real gamble—especially since it is usually difficult to identify the types of damaged components (particularly integrated circuits). But I took this little one in out of curiosity, hoping I might be able to make some progress.
The instrument produced no sound at its audio outputs apart from noise, crackles, and various artifacts. After opening it up, I discovered that the output operational amplifiers were not being powered correctly. The positive supply voltage was only +3.8V, while the negative supply voltage was a surprising +0.3V, even though both should have been at approximately ±6V.
The culprit turned out to be a faulty TPS65135RTER integrated DC/DC converter, a specialized chip commonly used in such designs to provide symmetrical supply voltages for audio circuits. Its negative rail was effectively shorted to ground due to a failure of an internal MOSFET. I replaced the converter IC, a couple of SMD ceramic capacitors, and an SMD inductor, bringing the device back to life.
All in all, not bad… 🙂
