PreSonus Eris E3.5 broke when turned on / teardown pictures

[wildiness]

After almost 2 years my PreSonus Eris E3.5 studio monitors broke when I turned them on. I flipped the power switch and the blue power LED didn't even turn on. I have turned them off and on less than 20 times during the time I used them. There are a few comments on other forums about these speakers blowing fuses when turned on.

I am under warranty for a few more days but decided to take off the back plate on the active monitor to see if I could repair it my self. The brown component(T2 AL 250V) by the red cables is the fuse and there is continuity across it, same for the black round thermistor. I also can't see any broken components or or smell any magic smoke. Caps all look good. All connectors are glued in with the nasty looking yellow glue so I am not breaking the board out further just yet. I think a lot of SMT's are hidden by foam on the underside of the board.

The amplifier chip is a ST TDA 7265 and the PCB versions v1.1 2018-05-04.

I don't think I can repair it but maybe some one else can spot the fault. Either way I could not find any pictures of the insides of this speaker anywhere else so I am posting these for future reference.

[status1]

As a general way trying to fix it I would start by looking over the solder connections of the through hole components especially the taller and heavier ones I would use a 4X loupe to look at the solder joints Because of vibrations they tend to crack the solder  That is the purpose of the yellow glue but sometimes they miss a spot or it's not enough

If nothing is found I would check for continuity and shorts than try to power it on an see where the power stops
If it's blowing fuses there is a reason for it

You may not be able to fix it but you may narrow down the problem area so perhaps someone could help out with a suggestion

[mrtrevisan]

Maybe I'd try to check wether the TDA7265 gets its supply voltage.
If it doesn't, I'd go backwards till I find a supply voltage (being careful), I should get an idea of what's the broken or "desoldered" component.
If the TDA does get a supply voltage, I'd then try to feed a signal into the line inputs and see wether it gets to the TDA input pins - and then output pins - as expected.
If you have a reasonable supply voltage reading and also input signal reading, but no output, I'd suspect the TDA has fried for some reason.

I also see there's a 3 pin TO220 device near the 400V 100uF capacitor. That too might be worth a look.
My 2 cents, hope it helps.

Cheers!
  Marco

[Audiorepair]

If there is no blue LED, then the power supply is not working.

If the power supply is not working because something is shorting it out, then you should hear some kind of ticking noises as it attempts to fire up then aborts.
Better still, connect a mains lightbulb in series with the mains input if you can, you will see if something is shorting the power supply by the flashing bulb.

[PeterL]

Old thread, but same speakers with the same issue here.

This seems to be a common issue for this product.

I started investigating the power supply, which wasn't working, then after a few powercycles while measuring on the primary side, it suddenly was working again.

So for now I can get the speakers working by turning them off for a few seconds, then turn them on again. You could give that a try also.

[netch]

Similar issue here. 2 years of troubleproof functioning and now refusing to turn on. The blue diod remains off ;(
Opened the back lid, have never seen such a messy board. What is the white stuff? Thermal paste? Whatever.
Checking for  obvious faults, the  multimeter beeps on the fuse and on the switch when it's on. So they seem ok. Visually couple of capacitors are swollen. Could they be the reason for not getting power on a diod? I suppose no, due to their voltage or..?
Any idea where to dig further? Could anyone reach the underneath of the board? I unscrewed everything but it doesnt want to come off. I'm afraid of breaking it if I'm to apply force. Thanks in advance!

[netch]

UPD: I changed two swollen capacitors and a small one which is 50v10uf in the powersupply section. All of them were way below the stated capacity. Now I hear light ticking noise coming from somewhere and the blue diode blinks at times, but that's it. I can not measure the supply voltage on TDA7265 as the voltmeter goes crazy. So I suspect something's wrong with power supply. Can i just change it? Or there is high probability that another component is shortening it out?

[rsjsouza]

The tick tick sound indicates there is a high current consuption taking place on the system and the switching power supply is failing to start. I would do a shotgun replacement of electrolytic capacitors, since the board may operate at high temperature and several of the capacitors seem to be third tier brands.

BTW, the "white stuff" is silicone glue to prevent the larger parts from becoming loose with transportation and operation of the product - a common feature of audio speakers, where the vibration of the bass will cause fatigue on solder points.

Good luck in your repair!

[GLouie]

There are reports of other brands of speakers (KRK, for one) having problems with the brown goop on the board turning conductive with age and causing similar problems. Maybe a thought after replacing the electrolytic caps. Make sure the replacement caps are low ESR for switchmode power supplies.

https://www.eevblog.com/2018/04/09/eevblog-1072-krk-rokit-6-studio-monitor-speaker-repair/

[djtimmy77]

Found this thread due to having a similar issue.  In my case I am certain it is simply the power switch itself, I have been having intermittent issues for a couple months, which I typically would solve by rocking the switch back and forth just slightly to get the monitors to stay on.  I was investigating a bit further and the rocker fell off with the slightest tug.  Going to look into replacing the switch with something more robust.

[djtimmy77]

The power switch is glued in pretty good so I bought an inline iec c7/c8 switch and bypassed the internal switch.  Back in business.

[bugijs]

Mine 2 caps looked exactly like that, I changed them, now the speakers work fine.

My issue was that the speakers where working, but making loud white noise and also dropping out when volume was turned up.

[shapirus]

Found this thread due to having a similar issue.  In my case I am certain it is simply the power switch itself, I have been having intermittent issues for a couple months, which I typically would solve by rocking the switch back and forth just slightly to get the monitors to stay on.  I was investigating a bit further and the rocker fell off with the slightest tug.  Going to look into replacing the switch with something more robust.

Haha, I'm joining the club.

In my case, the switch seems to be broken mechanically. It's stuck in the "on" position. I haven't yet taken the speaker apart, so no idea what happened.

I wonder if it's some standard type/size switch, or I'm out of luck if it has to be replaced. The rocker button itself looks quite standard, but the whole assembly I'm not sure.

Have you found anything to replace your switch with yet?

[shapirus]

I wonder if it's some standard type/size switch, or I'm out of luck if it has to be replaced. The rocker button itself looks quite standard, but the whole assembly I'm not sure.

So one of the plastic "half-axle" tabs simply broke off.

Thankfully, this type of switch is very common. I'm gonna order some from here: https://www.aliexpress.com/item/33058689541.html

Will post later to confirm that it's a direct replacement (or not).