Behringer B2030A repair

While one worked perfectly as described, the other was doing a little more than just "buzzing". On power-on, it popped incredibly loudly, hitting the internal amp's limiter before dying down to a moderate buzz over a few seconds. Occasionally, the buzz would die down to near-inaudible levels (but never entirely) and it would work perfectly. Most of the time, the buzz remained constant and the woofer would make a demonic scream every time something remotely bass-heavy was played. In retrospect, I should have recorded this.

A little bit of research (and I mean a little) led us to believe it could be caused by radio interference from a long wire internally controlling the front status LEDs. We quickly pulled the front plate off and found the small set of 4 wires we believed to be responsible. We unplugged them and powered it back up, only to find there was no boom or buzzing! We thought we'd found a ridiculously easy fix. To verify our solution, we reconnected the LEDs and powered it up, only for the boom and buzzing to return. Feeling quite chuffed, we re-disconnected them, put it all back together, and set out to make some nice cables for them, as I didn't have any long RCA to 6.5mm TRS cables.

If you glance ahead at this recount, you'll notice there's a little more to go. That's because we had just gotten unlucky during our initial testing. We returned with our freshly crafted cables, keen to set up the monitors in my living room. However, upon powering them on, we were immediately greeted with the same, quite obnoxious, boom followed by the buzzing. We decided to call it a day and planned to return two days later to have another crack.

Instead of trusting the first Reddit post we found, which referenced a 2010 Fixya.com post with a single answer from 2011 about a different model (the B2031A, not our B2030A), we gave it a little more thought.

• The issue persisted with no source. It only needed power to reproduce thus it wasn't a bad source or interference in the cables.
• Similarly it wasn't a ground loop because there was only one ground. Nothing to loop.

A well know problem to the Behringer Truth B2031A speakers is radio interference and noise. I had the same problem with mine and found a solution on a forum!

If you open the speakers, you'll see a cable from the main board that runs to the 2 lights at the front (on/limit LED's). It functions as an antenna… Disconnect it and your speakers are silent, finally. (OK no leds, but I can live with that). — Anonymous

The forum that the anonymous Fixya.com user referenced is lost to us, but it's clear now we neither had the same speakers nor the same issue.

We theorised that the large boom and fade-out could be caused by a capacitor behaving badly. The internet seemed to think that bad capacitors can cause all sorts of odd issues, so it wasn't unreasonable that one was also the culprit here. Additionally, being 20-year-old speakers (the previous owner had kept the original documentation, dated 15 April 2004, 6:30am), it wasn't unreasonable that something had died or was dying internally and was due for replacement. This would also explain the lack of issues when we first tested them, having them unplugged for some period of time may have been enough to discharge the capacitors and avoid the issues, quickly powering it back up after reconnecting the LEDs would have been too fast for them to discharge again.

With no practical way to test the capacitors while still on the board, we chose to focus on the two large capacitors that showed visible signs of wear.

Before beginning our second day of attempting to restore these speakers, we stopped off at the closest Altronics store to pick up some replacement capacitors and discharge resistors. This was about a $10 shot in the dark, but we didn't feel like driving 40 minutes just to pick them up from a specialist store when we could get them on the way. And good thing we did - after de-soldering the two large capacitors, it was clear the damage was not just superficial. We're not entirely sure what happened, but there appeared to be significant corrosion which had potentially killed them.

Unfortunately, one pin broke off during removal so we were unable to test the damaged capacitor. The cleaner-looking one failed our resistance test, unable to hold a charge³.

A little cleaning and a quick soldering job from a mate with a steadier hand than mine, and we soon had two freshly attached capacitors.

After wiring the pre-amp and input source (my headphone amp and phone), we stood a safe distance back and powered it on. We were greeted by a relieving silence. No boom and buzzing was a fantastic start. We fired up some tracks to test it, the first being "Holly" by Sick Love, a personal favourite of mine, and put the speaker through its paces.

Convinced it was working perfectly, we promptly went for a well-deserved swim to cool off, waiting to close the speaker back up until we were no longer sweating profusely.

The pair of speakers has been sitting on my desk and serving me very well since. I love them. For approximately $90 in speakers and parts, plus about the same in food, cables, and other miscellaneous items, I think they turned out great.