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Showing posts with label voltage regulator. Show all posts
Showing posts with label voltage regulator. Show all posts

Monday, 30 March 2020

#60 MOTU 8M teardown

Well, this one's a "biggie" - i had been lusting after one of these for a few years now, but the price was (and technically still is) on the prohibitive side, retailing at ~$1300-1500, depending where you look. Fortunately though, i've been stalking eBay off and on for one of these, and a used one happened to pop up just the other week, on auction. To my amazement and delight, despite there being at least 6 other "watchers", i was fortunate enough to win it for the opening bid, ie. about half the price of a new one.


Sunday, 8 September 2019

#50 Philips HTS7201 Soundhub Home Theater (2.1) teardown & repair

This just came in, with the symptom description of "will no longer turn on". Fair enough, sounds like a power supply issue then. Apparently this retailed around $400-ish when new (according to a 2012 review i found online) - not exactly bottom-of-the-barrel, but it's still very much in the mainstream/consumer range, so i'm expecting crap caps to be the root cause. But time will tell.



Tuesday, 26 March 2019

#38 Focusrite Scarlett 18i8 (1st gen) teardown

Yet another "sold as faulty" eBay catch - a nice little(?) Focusrite Scarlett 18i8 USB audio interface. Which turned out to actually have nothing at all wrong with it.


Admittedly, i went against the first commandment of teardowns (ie. "Don't turn it on; take it apaaaah't!.."), but only because it was the first troubleshooting step, and it used the same drivers as my Scarlett 18i6 "daily driver".

Friday, 9 November 2018

#32 M-Audio (Avid) Fast Track C600 teardown & repair

This little bugger, an M-Audio / Avid Fast Track C600, was listed as faulty on eBay - description said it would no longer power up, regardless of it being bus-powered or having its own external power supply connected. Got it shipped for 30eu / $30, so why not?



Tuesday, 2 October 2018

#30 Double Dock Day - HP HSTNN-I11X and Dell PR03X (USB 3.0) teardown

Right, so i had been on the lookout for a cheap docking station for my Dell Precision M4800 for a while, and the other week i stumbled across and ad on a local website about a clearance sale from a university - docking stations, laptop chargers, some desktops etc. When i finally got to their premises, instead of the $5-10 prices i expected, the guy there said i could have them for some coffee-change into the tip-jar, so i walked out with two PR03X's for a mere 40-50 cents or so - me happy!


The HP dock though, was about 15$, but came with a ma-HOO-sive 230W power brick, which is for another project; expect a teardown of the brick soon. Sadly the dock wouldn't fit my HP Elitebook 6930p (only the later xx40 Elitebooks), but that doesn't mean we can't take a peek under the skirts, and then resell it to make some of the money back, right?

Monday, 19 February 2018

#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.

Tuesday, 14 November 2017

#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.