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MX-1000 stopped working after I cleaned it!

woodhous

woodhous

New Member
(posted on another thread but reposting it here - thanks @avionic!).

Hi All! I'm another newbie audiophile who's got a MX1000 on the fritz (picked it up for a song (400 bucks) on eBay listed as not working - although shown as powering on), because I thought it would be a fun project!

Got it home, plugged it in, and turned it on. It was working! All three channels were good and clean crisp sound was coming out!

That said, the power button was stuck 'on', internals were a disaster. The primary circuit board was an utter mess and filthy. I took it apart to clean it (super carefully) with a brush, compressed air, and iso alcohol. Additionally, during shipping the speaker binding posts were utterly crushed and are completely shot. So I've ordered replacements.

The catch is, I put it back together, and now...no sound. The meter is reading correctly and it's powering on still. But it's not going into protection mode when it first powers on, and there's no sound out of any channel.

Any ideas what I did or where I should start my troubleshooting. I'm feeling like a real idiot.

Thank you!
 
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could be a bad solder joint making for intermittent connection. If it’s in both channels, it’s got something to do with power. Couple of suggestion:

Try using a chopstick to tap and push components, especially around the relays.

Do a visual inspection of the solder joints. Use good light and a magnifying glass. These can be hard to see.

EDIT: Don’t feel like an idiot. It’s highly possible that this is exactly the same problem that caused it to be sold as not working. The chances are that the fix will be easy, since you already know it works. It might be hard to find, but the outlook is way better than one with toasted outputs.
 
Semanon said:
could be a bad solder joint making for intermittent connection. If it’s in both channels, it’s got something to do with power. Couple of suggestion:

Try using a chopstick to tap and push components, especially around the relays.

Do a visual inspection of the solder joints. Use good light and a magnifying glass. These can be hard to see.
Click to expand...
Thanks Semanon. Yeah there's no sound at all now, after there being perfect sound from A/B/C before I took it apart to clean it.

That definitely makes me think it must be a bad solder joint somewhere that I accidentally loosened up?
 
I don’t know that amp, but someone will be along shortly with some specific advice on where to look.

Speaker select button might also be a candidate for cleaning.
 
woodhous said:
The meter is reading correctly and it's powering on still. But it's not going into protection mode when it first powers on
Click to expand...
When you say the meter is reading correctly. Do you see the meters going up and down when playing music?

Can you clarify what it does when powered on in regard to protection mode. It should be in protection mode on start up. Protection light on for about 15 seconds or so. Then you will hear relays click and the protection light will go off. Is this what happens?

Also, channels are L and R. Speakers A, B and C are not generally referred to as channels.
 
Asmodeus2112 said:
When you say the meter is reading correctly. Do you see the meters going up and down when playing music?

Can you clarify what it does when powered on in regard to protection mode. It should be in protection mode on start up. Protection light on for about 15 seconds or so. Then you will hear relays click and the protection light will go off. Is this what happens?

Also, channels are L and R. Speakers A, B and C are not generally referred to as channels.
Click to expand...
Hi Asmodeus!

Thanks for the help. Sorry if my explanation was bad (I'm still learning the ins and outs!).

When I first powered it up (pre-clean), everything worked - relays clicked, protection mode went off after about 5 seconds or so. Essentially what my (working) M85 does.

Post-clean (but I will say that the speaker binding posts for A/B/C are toast and I am replacing them), no protection mode on start up, no relay click.

I've recorded a quick video for reference!

Thank you so much!

EDIT: I forgot to mention, in this video, the meter is NOT working. However, earlier today the meter was working when I was playing music through my pre-amp into the MX1000 (although there was no sound coming out of A/B/C. I was getting normal meter action (going up and down). Now the meter is reading null and not moving. So strange!
 
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Well, certainly looks like something in the protection circuit is amiss. I am suspicious of the damaged speaker terminals. The boards that they are connected to have the speaker protection relays on them. There is also very little clearance for these boards. If you haven't already, please check that these boards are not pushed back or moved in such a way that they are touching something that they shouldn't. Or that the boards themselves are not damaged. Cracked or components dislodged or something.
 
Ditto on fixing those speaker binding posts. I would absolutely not fire up an amp with those damaged.
 
Semanon said:
:lurk:
Click to expand...
Ha! Sadly it's way more complicated to put in new binding post than I thought...hoping to get through it this weekend, but having to create a new mounting board for the posts, solder together the posts to new copper wires then solder those to the PCB. A bit crazy over here...
 
Ok new binding posts are in (not perfect, but I've never done something like that before!).

Sadly nothing still. No sound, no relay click, and no meter. So I should go troubleshooting in the protection circuit?

Before:
IMG_8844.JPG

After!
IMG_8901.jpegIMG_8902.jpg
 
woodhous said:
(posted on another thread but reposting it here - thanks @avionic!).

Hi All! I'm another newbie audiophile who's got a MX1000 on the fritz (picked it up for a song (400 bucks) on eBay listed as not working - although shown as powering on), because I thought it would be a fun project!

Got it home, plugged it in, and turned it on. It was working! All three channels were good and clean crisp sound was coming out!

That said, the power button was stuck 'on', internals were a disaster. The primary circuit board was an utter mess and filthy. I took it apart to clean it (super carefully) with a brush, compressed air, and iso alcohol. Additionally, during shipping the speaker binding posts were utterly crushed and are completely shot. So I've ordered replacements.

The catch is, I put it back together, and now...no sound. The meter is reading correctly and it's powering on still. But it's not going into protection mode when it first powers on, and there's no sound out of any channel.

Any ideas what I did or where I should start my troubleshooting. I'm feeling like a real idiot.

Thank you!
Click to expand...
OK-- When the binding posts got smashed , did the relay board get broken ? I suspect it got cracked. I suspect broken traces on the relay/binding post circuit board.
 
avionic said:
OK-- When the binding posts got smashed , did the relay board get broken ? I suspect it got cracked. I suspect broken traces on the relay/binding post circuit board.
Click to expand...
Not that I can tell. I just spent a good chunk of time with it soldering in the new binding posts and it looks ok to me. No cracks or anything!

It also was working before I took it apart to clean, so I assume it was something I did then like a total newbie :(

I guess I could go through circuit by circuit on there and see if anything registers as open?
 
Iso alcohol is both flammable and electrically conductive. Any wet residue can screw things up, be sure everything is completely dry of it before powering it up.
 
Odd that you have no power light when you have meter lights. I believe the 1000 lights and meter are very similar to the 80/85 in that if there's a meter board issue you might have a broken circuit to the power light. I just had an 80 returned to me with that issue and the meter board was cracked and 11 traces were open due to shipping morons. Could you have a couple of issues with this one? Speaker board and meter board? Cracks can be very difficult to see at sometimes. Perhaps it was making connections and the disassembly caused already present cracks to open?
 
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