Alesis Monitor One MK1 Passive occasionally cutting out

[FCTRdotNET]

OK, first of all, with a little research, you'll see that the REAL reason for all the RA series amp failures are the crappy DONG-WOO relays Alesis chose to use. RA-150, 300, and 500 all have the same problem. Simple solution for the RA-300 (providing you can solder/desolder or have a friend who does):

* Buy one NTE R25-11D10-12 (at $6.24)
* Disassemble the amp (6 screws on top, and four on the side, inside the heat sink fins, the inside screws)
* Carefully unscrew the power supply board (it's the one on the bottom with 4 screws and one screw that holds the rectifier)
* Using a 40w or higher desoldering tool (or solder braid), remove the black relay (8 contacts, total)
* Replace with the NTE one you bought
* Reassemble

Voila! One working amp! Total bench time? One hour. Also, check out the 10000uF 63v caps. If they are bulging or "rattle", replace them, too.

-=> Andrew
From Concept To Reality, L.L.C.

[Ichiban Rei]

That is awesome advice! I've actually upgraded to a pair of Tannoy Reveal 601Ps and the sound is leaps and bounds better than the Monitor ones I struggled on. I do notice that the right speaker cuts out at times at low volumes. Being handy with a soldering iron, I'll be upgrading the relay. Thank you SOOOOOO MUCH! I had figured this post was long dead and forgotten.

[emrr]

If the speaker is for sure doing this (does it with different amps driving it), it's probable that components on the crossover have sheared off due to vibration, and are making intermittent contact. The crossover is mounted directly to the jack plate on the back of the speaker. I have had to replace caps and resistors with legs sheared through on several occasions.

[Ichiban Rei]

Its not likely since the tannoy are new. It could be a defect tho. I'll switch their position and see where it cuts out.

[emrr]

Sure; just adding a general comment about monitor one problems I've seen.