SOLVED - Need help with Focal Solo6 Be repair?

[chilidawg]

Actually, the via for the resistor is underneath the 22uF/35V capacitor, so the wire can't poke through.

 

[Khron]

Ah, fair enough then. Still, i'd kinda prefer avoiding wires "flapping around in the breeze", sort of out of principle

 

[chilidawg]

The old principle don't fix what's not broken still applies?

If I wanna go the extra length, I could probably tack it on the board with a drop off non-acidic, non-conductive silicone glue.

But for now, the monitor is working nicely. Had both of them connected to my phone headphones out and I was listening to some music. Also recorded a short demo video but it has too much background noise from across the street (my neighbor is installing a steel fence and awning, so the workers are grinding a lot)

Well, I gotta admit, they did sound great, despite the cheapish construction and the low-quality PCB.

Anyway, thanks for all the help.

 

[chilidawg]

Khron, just to let you know that I shortened the jumper wire (and also saw what my solder tip has done previously to that yellow box film capacitor, ahahaha, oops! if I have 220nF in my bin, I would have replaced it too)
Wire is now flat on the board, but not touching any components at all. Cleaned up the dirty flux as well..

Since then, I haven't turned it off. I'm abusing it and pushing it to the limit, just to see if it is going to crap out at some point, but so far so good, even thermal wise. First time trying this HY410 thermal paste.

Video has 10s of copyright audio material, since I was playing some random songs on YouTube. If we're not allowed to have that kind of content here, feel free to remove it.

 

[alphasnk]

Congratulations Chilidawg you've made it!!

 

[fazer]

Way to hang in there Chilidawg.

 

[chilidawg]

Thank you all

 

[chilidawg]

Btw guys, just a quick question.

This is the main fuse they use for this monitor. In case someday it blew up and I will have to replace it, do you know what type of fuse it is? I can't tell just by looking at it. I think it's a slow blow type, but I could be wrong, because most of the slow blow fuse that I see being sold in this country has a twisted wire inside the container, unlike this one.

 

[Khron]

Read the markings on the end-cap.

[current rating] A [letter] [voltage rating]

The "letter" may be "F" for "fast", or "T" for "time delay", or just missing, for whatever qualifies as "normal".

 

[chilidawg]

Thanks, had to Google'd about fuse, and what T1.6A L meant, confirmed it's a time delay slow breaking fuse.

Hard to find that kind of fuse here. I guess I will have to tell my friend to order up some from Aliexpress to keep as spares.

 

[ccaudle]

Hard to find that kind of fuse here.

Where are you located? That is a very common type of fuse which has been used for many decades. They come in different diameters and lengths, so you need to know the physical dimensions as well as the current rating, but any electronics distributor will have them, and even most hardware stores, at least in North America.

 

[Khron]

Looks like a pretty normal 5x20mm fuse.

 

[chilidawg]

All I could find locally is a ceramic version for this size, same amperage and voltage rating.
Seller claimed it's a Littelfuse time delay slow blow fuse. Ordered a few and will test them to see if they'll work.
For a glass version, in this size, only fast acting fuse apparently.

Red color radial fuse however, is a different story. I can get plenty of time delay slow blow radial fuse, so I was thinking if someday this glass fuse blew up, and there's no direct replacement to go in the IEC fuse cartridge slot, I will have to do a bit of modification to make it work.

 

[nOw]

Hello there good people, I haven't been here for a few years. Not in the pro audio world anymore.

Yesterday a friend brought in a pair of Focal Solo6 Be, and one of them has a bit of an issue. It has a super loud hiss and produce random crackling noise. Happens with or without a connection to the input.

I thought it might have something to do with the power supply, like a failing filter cap perhaps, but nope. They're all tested ok with values are still tightly close. I can't check for voltages because of the way it's assembled together (a garbage design for a thousand bucks of studio monitor, imho), at least not without damaging something in the process or getting myself electrocuted since there are both live AC voltage and high current high DC voltage running on the board.

There are two amps inside: one for the woofer using two pairs of MOSFETs combined together with a 2-way active crossover I think (all SMD parts), and one for the tweeter using an obsolete amplifier IC (National L4780TA), I don't see any physical damage with both circuits, and the speaker still outputs audio very well. Just not usable at all for listening. I haven't tried to isolate from which amp the issue might be generated because the driver cables are too short, and I don't have AWG18 cables at hand to extend them to the board. I could dismantle the drivers off the wooden box, but that will probably freak out my friend. Last time I changed the broken ON-OFF rocker switch, he was sweating like a bucket while watching me doing it, sooo afraid that I would somehow damage the speaker, lol.

Without a schematic, this repair effort is probably futile, but regardless, any kind of help is appreciated.

Hello there good people, I haven't been here for a few years. Not in the pro audio world anymore.

Yesterday a friend brought in a pair of Focal Solo6 Be, and one of them has a bit of an issue. It has a super loud hiss and produce random crackling noise. Happens with or without a connection to the input.

I thought it might have something to do with the power supply, like a failing filter cap perhaps, but nope. They're all tested ok with values are still tightly close. I can't check for voltages because of the way it's assembled together (a garbage design for a thousand bucks of studio monitor, imho), at least not without damaging something in the process or getting myself electrocuted since there are both live AC voltage and high current high DC voltage running on the board.

There are two amps inside: one for the woofer using two pairs of MOSFETs combined together with a 2-way active crossover I think (all SMD parts), and one for the tweeter using an obsolete amplifier IC (National L4780TA), I don't see any physical damage with both circuits, and the speaker still outputs audio very well. Just not usable at all for listening. I haven't tried to isolate from which amp the issue might be generated because the driver cables are too short, and I don't have AWG18 cables at hand to extend them to the board. I could dismantle the drivers off the wooden box, but that will probably freak out my friend. Last time I changed the broken ON-OFF rocker switch, he was sweating like a bucket while watching me doing it, sooo afraid that I would somehow damage the speaker, lol.

Without a schematic, this repair effort is probably futile, but regardless, any kind of help is appreciated.

I’ve had this strange loud crackling hiss coming from one of my Focals. I sent it to the only Focal certified technician in my country who decided it was the tweeter amp and replaced it. Two weeks later the noise came back with no input connected. He suggested replacing all the electronics which I did not agree to since it would cost $1000. Focal wrote to me and said it is not protected from the 4g/5g networks. The other monitor has had no such interference only the one which used to come and go. After 3 months of no problems, the noise came back this time it is constant. I even tried it in a different location and it still made noise. Any suggestions or help would be greatly appreciated.

 

[Disco Volante]

rant/ Sounds like you have encountered an instance of "certified technician without troubleshooting or actual repair capabilities". Most of these so-called techs are only able to do the most basic "open-enclosure-unscrew-unplug-replace-boards". Drives me bat shit crazy. I had the entire motherboard on my fancy-welder replaced by a certified Fronius repair agent for $1k. They wouldn't even give me the old board, so I could have fun troubleshooting it...
/rant

Read page 2 of this amazing post. A very stubborn member chilidawg found the fault in his monitors with only a DMM...

Cheers, V

 

[nOw]

Thank you for your reply. Presently I have the speaker at another service technicians shop. So far he has determined there is a heating problem and is trying to track it down. I will update when I have more info

 

[chilidawg]

Thank you for your reply. Presently I have the speaker at another service technicians shop. So far he has determined there is a heating problem and is trying to track it down. I will update when I have more info

I compared every components readout on my DMM.

Speaker A vs Speaker B.

Comparison was done offline first without power applied (checking resistance of every freaking resistors, checking for a short through and short to ground of every semiconductors) then went on with measuring voltages.
I video recorded everything on my phone. A lot easier than writing down on papers.

The differences I got with the voltages between the two speakers that actually revealed a specific location on the problem board where I was finally able to find the exact fault.

And btw, the good speaker that I used as a reference at the time, is now producing crackling noise every now and then, while the repaired one remains trouble free. I have to do this comparison all over again to find out why it's cracking.

 

[elskardio]

And btw, the good speaker that I used as a reference at the time, is now producing crackling noise every now and then,

I've been having this issue with one of my Solo6. My local authorized dealer said they replace the whole backplate + amplifier when this happens. $500... this is non sense

 

[nOw]

Focal Solo 6be update. The monitor is once again back at the original technicians shop getting another tweeter amp replacement. Really not 100% sure how or why the 1st replacement went south The good news is after purchasing these 6-7 years ago the store is willing to buy them back! In return I’m going to upgrade to the 3way Focal Trio 6. I was totally blown away when I heard them and hopefully will have next week!
Thank you everyone for your feedback.

 

[chilidawg]

Focal Solo 6be update. The monitor is once again back at the original technicians shop getting another tweeter amp replacement. Really not 100% sure how or why the 1st replacement went south The good news is after purchasing these 6-7 years ago the store is willing to buy them back! In return I’m going to upgrade to the 3way Focal Trio 6. I was totally blown away when I heard them and hopefully will have next week!
Thank you everyone for your feedback.

I don't think the problem is with your tweeter.

I just re-opened the "good" speaker that I used back then as a reference to repair the bad one because it is now going bad.

I measured the woofer amplifier power MOSFETs. Gate and Source pins are identical, however, on the Drain pins of the negative signal I don't have DC, but on the Drain pins of the positive signal I have 170mV DC (apparently also goes randomly to 0.5V, sometimes 1V) That's why the woofer is making a constant crackling noise and the cone moves and makes a loud pop upon powering on and off.