#68 Alesis M1 Active Mk2 rehabilitation, part one

Over on the Badcaps.net forums, a thread was started all the way back in 2010, about power supply issues in these arguably "classic" low-cost active studio monitors. It even ended up being stickied just this winter, so it's been quite active and useful. It served as motivation for myself, to take up hunting for faulty ones - not sure if i had gone through three pairs, but at least two pairs i revived and sold off to a couple friends, some 7-8 years ago, and to this day i've yet to hear back about any further issues, so i take that as a good sign. In the mean time, i still contributed with thoughts and advice there, which helped lead to several successes.

Recently, a fellow forum member there got fed up with his failed attempts to revive his pair of monitors, and got himself a pair of new ones. In that context, we struck a deal for the Alesis'es, and a few weeks later, here they are.

#67 Audient iD22 part 2: the repair

 And now, getting back to the issue affecting this unit... As pointed out in the ad, the LT3439 apparently used to have a piddly little heatsink glued on top of it, but it got detached. Now, there's a chicken-and-egg type mystery here - did the heatsink glue fail because the chip overheated in the first place? Or did the chip get fried because the heatsink fell off? Regardless, investigation showed that one of the two switching transistors inside the chip seems to be stuck in a conducting state, despite the transistor itself not being shorted, though. But since it handles all the power for the analog circuitry, it's no shocker (no pun intended) that only the digital ins & outs work. 

#44 Ram Audio S6000 teardown & repair (rebranded as LD Systems SP 6K)

A good buddy and neighbour of mine had one of his amps kick the bucket in the middle of a gig (one i was helping out on, as well). On the bright side, noone noticed, only when turning-off time came. The beast in question was one of his two LD Systems SP 6K amps (rebadged Ram Audio S6000).

#28 Active full-range surround speaker project (BN96-12832 & TPA3118)

Since the "unofficial" theme of this blog seems to be repair, recycling and repurposing (more or less), i finally got around to getting knee-deep into this idea, which i started devising quite a while ago - a pair of "slimline" surround speakers.

Disclaimers:
 - No, these are not meant (or supposed) to be "hi-fi". More just for a bit of "ambient noise", if you will, for movies with 5.1 soundtracks. That, and possibly alternative monitoring for checking mixes.
 - No, these are not meant to go terribly loud. Due to, let's call them, physical constraints, they'll be placed at the corners of my sofa (right up against the wall, opposite the TV and the "mains"), so no huge SPL's are required.

#27 Samsung 5V 1A ETA0U81EBE USB travel charger

This one's a quickie, but i figured i might as well document it.

A friend passed me this a few weeks ago, not quite sure why. I don't recall it being mentioned as dead, only not-used. Either way, last night i wanted to charge the battery inside my modded M-Audio Fast Track, in preparation for a local gig next week. Upon plugging it into this thing, the power LED flashed up for an instant, then nothing. I figured it might not like the USB data lines being tied together, as they often are, in chargers; it powered on and worked well with another charger. But that prompted me to crack this one open.

#26 Cheap & easy DIY LED light panels

Recycling's all the rage nowadays, right? Right..? Well, either way, freebie raw materials for projects are always welcome, that's something i'm pretty sure we can all agree on. Now, i'm not admitting to be a hoarder, far from it, but i kinda-sorta couldn't bring myself to throw away the dead (read: cracked) laptop LCDs that i had replaced for various clients at work. And what with "finally" expanding this blog onto YouTube, i figured i'd need some extra lighting for the workbench. Catching my drift yet?

#25 Behringer ADA8000 "Ultragain Digital" revival

I got my hands on one of these Behringer Ultragain Pro-8 Digital a few months ago, as faulty (as in, totally dead) for about 50$ shipped. Having done some preemptive googling before going for it, i was expecting the transformer to be toasted. Sure enough, that's exactly what the problem was - one half of the center-tapped primary measured in the hundreds of kohm, so pretty much open-circuit (as opposed to the 50-odd ohms the remaining good half measured).

Initially i was planning on finding / getting a "drop-in replacement" toroidal transformer, ie. similarly sized physically and power-wise, but with less insanely-high secondary voltages. The stock one, according to some "inspection notes" i found online, seems to have had roughly 2x20VAC windings for the analog +/-15V (meaning the voltage regulators had to "burn off" uselessly much power / voltage), 12VAC for the 5V regulators, and a whopping 58VAC winding for the phantom power regulator. That's about a 50% overkill across the board. One can only wonder just what possessed them to spec the transformer quite like that, especially since it must've been a custom order - you'll rarely find retail units with more than two (identical) secondary windings, and when you do, expect to pay a pretty penny for'em.

#20 SM Pro Audio TB202 power supply repair

<Some sort of continuation from another post>

Buuuuut that brings us to what might as well amount up to the proverbial "elephant in the room" - the power supply. No markings or label anywhere on it - if i didn't know any better, i could almost say it never had any (no adhesive residues or anything). Fortunately, it was held together with four Phillips-head self-tapping screws, so "disrobing" it wasn't unecessarily traumatic. That being said, what greeted my eyes, sort of WAS.

#11 sE Electronics sE X1 rebuild

It's been a good few years since this mic (sE Electronics X1) came into my possession. As many others i have, i bought this one as faulty. The main problem was, it was noisy as hell (think wind-noise, or the sound of blowing straight into a microphone).

Once i had another capsule to test this with (a temporarily removed capsule from a Shure KSM27), i figured i'd hook it up to the X1 to see whether the capsule was the source of the noise. Nope, the noise was still there. After i ruled out the (stock) capsule, i replaced it with a 100pF styroflex capacitor, for minimal hassle (and risk of damaging a capsule) during subsequent testing of the electronics.

#6 Canon EOS 400D / Rebel XTi troubleshooting & repair

I got this old EOS 400D from a friend for about 35 bucks. She said it won't power on, even with a fully-charged battery. Might as well have a crack at it, eh?

On the outside it seems to be in pretty good shape. A bit of dust here and there, but hey, it's about a decade old, whaddya expect? Battery checks out fine, reading 8.15v, so that's definitely not it.

As chance would have it, between being offered the camera and receiving it, i did some digging around online, and i came across this little story here (scroll down to the second half of it). Could i (also) be fortunate enough to only need to swap out some fuses?