Alesis M1 Active MII - power went out

Hi-

These are about 3 yrs. old, so no longer under warranty. I turned them on today and within a few minutes I heard a little "pop" (pretty much the same sound they make when they turn on), and the power LED was out -- one monitor only. I wasn't playing anything through them at the time.

I tried a different outlet & a different power cord, but nada.

I'm wondering if anyone knows what it might be, what kind of place I should take it for repair (assuming returning it to Alesis would be expensive, but I don't know), and what kind of expense I might be looking at.

Thanks-

-Susan

If not, there may be one inline inside.

Hi gustabo-

No, in fact I just checked the manual and it says "No user-replaceable fuse is required because nuisance tripping is eliminated". Well, I'd call this a nuisance!

Thanks-

-Susan

I just saw somebody here say "the fuse is good", so now I'm wondering if in fact there is a fuse of some kind inside.

Shoot, what a pain. I'll post at homerecording.com and see who they recommend in my area.

-Susan

I just read the blog gustabo linked to. Check it out, it might actually be your problem. If so, taking it to a local shop or even a community college electronics department would be a cheap repair job.

Send it to me and I'll try to fix it for you, I'm partial to anyone named Susan
(especially a Susan with a dog)





(edited for clarity)

Sent you a PM

bitflipper


The dog gets 'em every time.

LOL!

I took out the fuse and it "looks" fine to me -- there's a single unbroken filament in it.  I don't know if there's any other way a fuse can be bad, but I'm going to replace it anyway. Radio Shack says they have them (but I've heard that before...). I'll take it with me, of course.

The C8 capacitor doesn't look corroded to me, but there's some gunk next to the big black things:



I don't know how much if any of that is normal. I can't really detect a burned electrical-type odor, or if I can it's very faint and might well be in my mind.

BIG thanks to gustabo for being so generous with his time & expertise! All digits crossed it's the fuse after all.

Thanks again-

-Susan

Wow, that picture's huge, sorry! I thought I'd scaled it down...

Anyway, yes I very much enjoyed talking with you, too... <cough> "gustabo" <cough> -- must we keep up this charade ? It's nice to put a real voice with a name (one that doesn't sound like a male version of me ).

So do you think it's not even worth it to try replacing the fuse? There's nothing really "local" out here in the boonies, and as I said if the filament's not broken I don't know if I should bother.

I'll call around and see who might be able to take care of it, and maybe get an estimate.  I know it's hard when they can't be absolutely sure what the problem is until they see it, but I suppose they have tools for testing the different components.

As you can probably tell, this makes me nervous ! I used to have a guy not far away I trusted with this kind of stuff, but he went out of business a few years ago.

Anyway, thanks again, and I'll keep you posted.

-Susan

From that picture, it looks like you have some burned up circuit traces. And possibly a burned up diode (?) in the lower left of the red box.

If the diode went bad, that could possibly allow enough current to flow in the traces to burn them up. A number of things could have started the progression towards this end.... including the capacitor... usually burned up traces, caused by excessive current are a symptom of the problem and not usually the problem themselves.

If you look carefully, you should be able to figure out what trace connects what points together.... a tech  who is handy with a soldering iron can easily fix the traces, and then track down the offending part and replace it... a diode is a few cents, a cap is a few bucks... not expensive, but hard for the uninitiated to figure out what part is bad. Removal of the parts, and testing outside of the circuit is best.

Not a fun job by any means without a schematic of the circuit.


It looks to me to be in the power supply portion of the circuit....the metal heat sink looks like voltage regulator transistors......  bridge rectifier diodes setting above the bottom cap.... if a diode want out (shorted...not open) , the one below the cap......  it would allow current to flow and burn up the traces... if that is the case... a new diode.... repair the traces and it should work again.  Let's hope it's that easy. Be sure to check the board's backside for traces as well.


Best of luck.

Susan G


Hi guys-

It wasn't the fuse, that would've been too easy!, so I'm on the hunt for a recommended repair spot near here before I take gustabo up on his *very* generous offer.

Alesis wrote back: "On a component based level we would not offer repair support however I can recommend some 3rd party service centers which are familiar with our products for nonwarranty estimate repairs: " and listed a place in NJ and one in CA.  I've asked them if a circuit diagram is available.

I'm tempted to take the back off the other monitor just to see how different it looks.

What I wanted to avoid was taking it in somewhere and saying "It's broken, please fix it!", so all your feedback has been very helpful!

Thanks again-

-Susan

Yes... expensive electronics will always jump into the path of certain destruction to save a helpless 59 cent fuse.

here's some sites that might get you the schematic:

http://www.free-service-m...Service_Manual_L78229/


I googled >> Alesis M1 Active MII schematic  and not much came up....  I didn't poke around in the site above.... if I needed the schematic I would first call the company and ask for a PDF of the schematic....you might be surprised... they just might email it to you.

I have a few schematics that were sent to me by the factory as well as the repair shops....

FWIW it may be worth replacing C8 and R4 in the PSU even if these are not the immediate cause of your problem as your blue light is totally out. It seems to be a design fault that the heat from R4 dries out C8.

I had this happen in both of my M1 MkIIs withion 6 months. For one of them I bought a replacement PSU for lots of £'s and the other I replaced the two components for very few £'s. Guess which was the most pleasant!

To quote another thread

"The flashing blue LED and loss of sound on the Alesis M1 powered monitor is caused by failure of capacitor C8 (220uF, 35V) on the power supply board. It dries up due to its proximity to resistor R4 (47K, 2 W) which gets very hot. This is a design fault.

Remove the power supply board (4 corner screws and 2 mains connector screws) and disconnect the two plugs. Carefully desolder C8 and replace it. Its value is not critical (220 to 470 uF will do) but it should be a 105 deg. type, preferably at 50V.

Remove R4 and replace it with a similar resistor with its leads bent so that it is nowhere near C8, otherwise the fault will return. One end may be connected to one of the existing R4 solder pads (furthest from rear of board), and the other to the top end of resistor R3. Check that you have connected it correctly by inspecting the PCB tracks.

Replace the board and all screws and plugs before testing"