BOSE Solo 10 Help - No Power Up - Pics + PCB Part List

[Pingo]

You're welcome!
That 21-2 chip is a wild guess, but with my poor knowledge of these parts I do not see another alternative for this so-called secret chip. but it could be decisive, for a possible repair!
incidentally, it could also be that the FAN chip is broken only. furthermore, it is sensible to measure all the conceived parts, before switching to parts exchange!

Cheers

 

[Jordan3Dtek]

Ya my honest hope is only the FAN chip, or something I ordered lol. I will definitely try my best to find the offending chip for knowledge, and so I can help you and possibly many others. Might even be able to start an ebay listing with a repair kit if we can find out exactly what is the offending component is, and a certainty that its occurring somewhat frequently.

**Just wanted to add; Got the board here and I am testing short to ground on pin 5 and 4, the Pin 5 is ground and pin 4 is FET Output, so I think that is correct far as I know.**

 

[Pingo]

We will see if we can bring a solution for the people with this complaint! It is a very common problem with these devices and that looks very coincidental!
But operating hours will certainly also play a role in many cases. Incidentally, these chips are super sensitive to failures. So do not forget your anti static wristband when soldering these chips.

Greeting from the Netherlands

 

[DarkRye]

Hello Folks!

Sorry to perform post necromancy, but I am diagnosing my own Bose Solo and need only minor assistance you can provide from your own intact units:

This unit does not power on or react. Initial inspection at the inputs to the Bridge Rectifier (BR1201) looks good 120V. There is no output across the other two terminals. I removed the faraday cage and found a burned SMD element next to the BR1201 that is likely the follow up problem to replacing the bridge.

In the absence of schematics, has anyone identified what the bridge and SMD components specs are?

Best,
Rye

 

[dave9]

^ The PCB should have a letter/number designating the burnt component. The first letter of that is a strong hint what it is. I can't see the pic very clearly but first guess would be a (c)apacitor or (d)iode.

Based on your description of "no output across the other two terminals", assuming you had switched the meter to DC volts since it would then be DC, it suggests your bridge rectifier is fried. You could substitute any standard bridge rectifier in the same package size with a 200V or higher rating, and amps in that size would surely be enough, but odds are high it has a part # on the side that you will see when you remove it and then you have a target for a closer to exact replacement or a cost effective equivalent.

 

[DarkRye]

I've made some progress actually, the Bridge Rectifier was burned as well.

Part Identifier "China 1409J GBL06" with spec "DIODE, BRIDGE RECT, 3A, 600V" according to a service manual previously cited in this discussion. This exact part is manufactured by Vishay (GBL06-E3/45), please note that the package size "4-SIP, GBL" matters because this is a through-hole mounted part (http://www.vishay.com/docs/88609/gbl005.pdf).

In better pictures of an undamaged PCB, it looks like a resistor with the marking "750" on the top. This leads me to believe it is one of the two "75 OHM, 0603, .1W, 5%" spec'd resistors, but when I removed it I noticed that its physical size is 3.2*2.5 mm which corresponds with a Metric: 3225 or EIA: 1210 in the BOM. I inspected a nearby "471" resistor which correctly measures as 470 ohms, but also fails to correspond with the BOM specified size. I believe the other "750" marked resistor, if it is present, is beneath the DSP Faraday cage which I am hesitant to penetrate.

I think I will just order a "75 OHM 5% 1/2W 1210" from Panasonic to replace it.

I realize that the package size of a resistor basically doesn't matter when the more pertinent specs match and the part will fit on the footprint, but I was hoping for community insight and to provide some information for folks looking for answers in the future.

// EDIT: Correct the specification of the Panasonic replacement part.

 

[DarkRye]

Follow up: I have a working and broken speaker with the same PCB now which is great for testing and identifying problems. So the visibly damaged diode rectifier, 750 Ohm resistor, and FAN chip have been replaced. When I plugged in the speaker, the 750 ohm resistor blew up again. The diode is OK and the FAN ship looks okay.

The current draw through the resistor much have exceeded the 0.5W rating. There are two transistors in series marked, "FCB 7N60" controlled by the FAN chip upstream of the damaged resistor. On the working board, the resistance across the terminals is substantial and consistent. On the damaged board, both transistors read different values. This leads me to believe these chips need to be replaced. I will likely need to replace the FAN chip again to be sure it is OK.

The silk screen label reads, "HS1201" and "HS1202," but I have not found the corresponding component in the BOM referenced earlier in this thread. Based on the "F" logo, this appears to be a Fairchild 600V 7Amp MOSFET TO252 (D-PAK). I verified that the component fits the dimensions described in the most recent revision of this component (https://www.onsemi.com/pub/Collateral/FCD7N60-D.pdf).

Because these appear to be drop-in replacements I will order a handful and see what happens.

 

[DarkRye]

I am back to report that replacing those MOSFETs did not have the desired effect.

I was probing around the working board and discovered that the 75 Ω resistor (incorrectly called 750 above) is NOT what I thought it was. On the working board, the resistance across this resistor is close to zero. Furthermore, the component appears to be "75|||" or 75M" or "75X"

According to: https://community.bose.com/t5/Home-Theater/Bose-Solo-Tv-Speaker/m-p/246924#M21609
It is R075, 2512 SMD Resistor 1W 0.075 ohm 0.075R R075 1% 2512 Chip Resistor High Precision

Lets see if that solves it.

 

[marathony]

Hey Guys, I know this is an old post now but wondering if you guys manage to fix your units? I am in the same boat as you, have managed to open the unit and measure DC output so power supply seems to work ok. But that's where I seem to get stuck. Any help would be greatly appreciated.

 

[DarkRye]

I put a fair bit of money into mine. I wish I had a schematic and gerber because I kept finding other problems up-stream. I can power up the speaker with a 24V supply, but the AC to DC is not reliable.

 

[marathony]

Thanks for getting back. oh ok so your unit actually works! That means your power supply is faulty. Maybe on load your power supply fails. might be worth doing a mod and bypassing the power supply, and having a brick outside? also could you show me the points you input 24v? I might just do that to see if the problem is the same. If it is I might just do what I said and get the unit functional. I have seen this is many Bose products now that their powersupply over time fails. Poor quality components or over engineered design I would think.

 

[DarkRye]

I've had a busy few days - if you're willing to stick around till the weekend I will happily show you where I got.

 

[marathony]

That fine, I'm in no rush. This is just a side project hoping to get some experience and possibly a fixed device. And if I can manage to do a mod or fix it I'll post my finding here so others have a chance to save their units. Seems like a lot of people are in same situation with these Bose products.

 

[dave9]

I don't have all the info specific to this amp in front of me, but if the bridge rectifier doesn't check out, seems simpler to just replace that than to try to devise an alternate PSU you have to tap into the circuit.

 

[marathony]

At the moment we don't know where the problem is. My board is not turning on at all but DarkRay's board is. So I'm going to first find out if it turns on with external power if it does then I know something is wrong with powerfully side, even though I get 24V but sometimes you could have 24V but under load power supply could be plating up and I don't have expertise or schematics to work out what could be wrong. This particular board has some kind of check built in so if it doesn't have certain things in place it turns the power off before the unit fires up. So I have thinking Wirth my limited knowledge to just attache external 24V supply and start using the unit. If anyone has more knowledge on the power supply side we can work together and try figure out the problem.

 

[marathony]

I've had a busy few days - if you're willing to stick around till the weekend I will happily show you where I got.

Did you get a chance to take a look? also how many amps you set the power supply to?

 

[cesposito00127]

Hi guys!
I'm in the same situation like all of you. Could you please let me know if any step on are been done?
Tks

 

[marathony]

Hi guys!
I'm in the same situation like all of you. Could you please let me know if any step on are been done?
Tks

I'm stuck and was waiting on DarkRye to show me where he supplies 24v so I can try it on my board. He did say he was going to let me know when he gets a weekend free.

 

[DarkRye]

Hi folks,

Sorry for the delay - it's been busy at work and I've been trying to sort out my home office.

First thing to do, if you have a precision power supply, is try to power up the speaker with the 24V rail.

• Provide 24V 0.2A to the six capacitors, (+) is center, (-) is the exterior also marked with black line on capacitor.
• My system draws about 0.130A and played the power connected chime.
• I was able to power on the speaker with my remote, confirming that all systems above the power supply are operational.

Regarding my previous progress, I traced the AC power from the outlet through the bottom of the board to determine where the 120VAC dropped. Originally the 120VAC was available at the input to the bridge rectifier (see post #26 in thread). Around the same time, I replaced a resistor and FAN chip.

Today, I reflowed the FAN chip to ensure continuity and attempted to power up the system from the wall. The AC fuse blew at some point (pictured in red in photo_2021-04-04_17-41-06.jpg) so I wasn't able to make much progress. I replaced it with a wire short today to continue diagnostics. Instead, the same resistor (R075, 2512 SMD Resistor 1W 0.075 ohm 0.075R R075 1% 2512 Chip Resistor High Precision) exploded.

So what is my plan? Remove the burned resistor, plug in AC again, and look for problems between the AC wall input and DC power stage.

Not sure if anyone else has any better ideas or components known to fail, but that's where things are on my end.

 

[DarkRye]

Follow up - removal of the freshly burned resistor has restored 120VAC to the bridge diode inner pins and the outer pins report 160VDC. I would prefer to install a fuse before doing more work, though the likelihood of it burning out is quite high as the damage has not yet been diagnosed. I have marked these points on the PCB for reference.

I connected the 24VDC rail to the board to trace where the 24VDC rail begins and where it goes. I noticed that the voltages across the diode are wrong (D1301, D2PAK SMD/SMT Dual Common Cathode, STPS10170CG-TR). There is negligible voltage drop in either direction despite its design as a silicon diode. So that is either a new failure, or one I was previously unaware of. I did not replace the chip described in post #19, so it is possible that the root problem is isolated to the switching circuit.