Need help with a Grotto i

[RVCJJ3J]

I just received a Grotto i through UPS that I bought online from a reputable seller I’ve made many purchases with and now the grill is fallen off or broken off I guess and won’t go back on. I’ve enjoyed a ML Dynamo for about 2 years but wanted to go with a .2 and couldn’t pass up this deal in the Grotto i. Now I can live with the grill off for now but what I can’t live with is there is no sound coming from the speaker. The LED on the back panel is yellow when switched to standby and green when put on any other setting yet there’s no sound. I checked the fuse in the AC receptacle and it’s fine. I’ve checked cables and everything else I know to do and no sound. Any ideas would be greatly appreciated.

 

[ttocs]

Your Standby mode being yellow, and the Auto/On modes being green is a good start.

There's quite a bit of versatility with respect to the methods of connection. Which method are you employing?

Looking in the manual lists the titles of each method possible. Please specify.

 

[RVCJJ3J]

I was using only multichannel hookup. LFE in. I’ve since found a problem. I opened the box by removing the driver and here’s what I saw
1. 4 wire posts on the the driver, each receiving red/bird combo. 3 were unplugged from the post I believe due to rough shipping by UPS.
2. Inside top of cabinet had a printed circuit board with an exploded capacitor and a 1-1/2” diameter circular hot spirit. Hot enough for black in the center out to over half until turning brown. Printed circuit board has to be replaced.
3. I believe this board is the crossover but I’m speculating 100%. Hooked everything back up after clean out and vacuuming inside of case and achieved same result as before. Yellow light then green.
4. I don’t believe the x-over to be UPS fault. Gotta speak with seller. Everything else inside box appears to be excellent with approaching sublime build quality. I’m so heartbroken it’s gonna be a couple days before I can get to work on it.

Appreciate the response.

 

[RVCJJ3J]

In case anyone is still looking through this thread I finally have an update. After removing the board from the speaker and contacting ML customer service I found out that it was the amp that had burned up and needed replaced. I talked it over and ML sent me the replacement amp and it arrived just after the holidays. On a side note, and I'm sure most of you already know, let me say that Martin Logan's customer service is second to none. I spoke with Josh who was knowledgeable, courteous and professional. I really mean second to none. After receiving the amp it took me several days to actually getting it switched out but I finally got it 2 nights ago. Unfortunately I'm still not getting the Grotto i to reproduce a signal and now when I power it on I get a really weird squeaking/screeching sound. It's definitely coming from the driver, which by the way is getting power now, or at least the cone is stiffening up when powered on unlike before the amp switch when it did nothing. The noise sort of sounds like an old sci-fi movie sound effect maybe. It sounds electrical and it pulses on and off with rising pitch(frequency). It's not too too loud and it doesn't matter where the level control is set. Also it produces the same sound when hooked to my receiver as it does when it's not hooked to the receiver. Also it pulses with no common frequency. Any ideas anyone? I'll be contacting ML's customer service today but if anyone here has any suggestions I'm all ears. Thanks in advance.

 

[ttocs]

My first guess would be that the screeching sound is a short in the audio path. This is from experience.

Once, when I was reconnecting the LFE cable onto the RCA jack on the sub (different brand), I didn't realize the sub was powered on. The RCA plug shorted when both contacts of the plug contacted just the outer ground casing on the sub's LFE jack causing a screeching sound. It got my attention real good!

 

[RVCJJ3J]

This noise occurs without the subwoofer being connected to anything but AC outlet. However I did try hooking a cable into the LFE In connection with a cable from my working Dynamo sub with no difference to the weird sound and also no audio signal from the speaker. From my limited research I think it may be a problem in the servo control circuitry but again that’s speculation on my part.

 

[ttocs]

I guess my point is that you might try checking for shorts within the sub in the audio path.

Or,

sumthin' else is afoot.

 

[RVCJJ3J]

Thanks for the tip. Going through the boards now looking for shorts. None of this would’ve been possible without the help of ML’s service department. They’ve went above and beyond what anyone could expect, Thanks Josh at ML. Not sure if anyone cares but I’ll keep this thread updated in case someone in the future has the same problem. Before I forget thank you too ttocs.

 

[RVCJJ3J]

Well sir thought I’d let you know that the problem was a short. Fortunately Josh from ML sent me a replacement wiring harness and it cleared the issue right up. I’m at this moment enjoying the best bass that I’ve ever heard from a home theater speaker. I’m hearing things that hadn’t been revealed until. A short in the chain will definitely grab your attention. Thanks everybody and good luck in your endeavors I’ll remain humbly yours....R

 

[ttocs]

Peferct!

I love it when a plan comes together!