Makita DMR110N Repair - Now Turns On - No Sound

[Skezza]

I'm trying to repair a Makita DMR110N for a friend. It originally did not turn on. It was dropped from a reasonable height and failed. When I got it apart, a transistor had blown up. Same transistor as in this link:
https://maker.pro/forums/threads/replace-blown-component-makita-radio-dmr104.293953/
Which is a 2SB1143.

I swapped this out for a new one, and the device now powers up and operates correctly visually (all buttons work etc) however there's absolutely no sound whatsoever. You can hear that the speakers seem to be receiving a small amount power as there's a very very faint amount of noise which is common with powered radios, amps etc, but no matter whether I use aux, or dab radio, or FM, there's absolutely no sound whatsoever.

I've attached some images that show the component which I've replaced and also the rest of the PCB's. Are there any known failure points? I've reflowed the ET2314 which is a digital audio input processor and also what appears to be the amp chips solder connections, but this has made no difference as of yet.

Any suggestions? I was thinking of replacing the ET2314 but it feels like I'm just guessing.

I've uploaded some photos:

This is the transistor I've replaced, the same as the one identified in the other thread.

Reflowed the below:

 

[Martaine2005]

Do you have a function generator and scope?
I would get the data sheets of the ICs and see if signal is present at the input and also at the output.

 

[73's de Edd]

Sir Skeeza . . . . .
BOY ! . . just how many of those variants of the Makita Job Site units / boom boxes have we had posts of . . . . . . . but with their owners, actually being more savvy with hammers and nail guns, rather than basic electronics.
In my looking at your very last photo . . . . the speaker driving audio output module is being glaringly evident with its massive heat sink.
I emphasize the physical mass of that heat sink, since it would be most effective in giving a GOOD STRENGTH jarring of the MULTI connecting leads of that hybrid power module I.C. to its circuit board foils solder pads.
I wonder what the chance of that STRONG of a flexure of those pins, might have resulted in the opening up of a solder "ring joint" that was in the process of developing due to a minimal factory flow soldering layering along with actual usage . It being HOT while running while COLD on turn off, could have resulted in time related, progressive formation of that type of joint. The massive jolt encountered, then opened up a critical progressing ring joint .
ASIDE . . . . . .EXPERIENCED OBSERVATION . . . .this condition is additionally, particularly time related to wire wound and larger metal film resistors leads solder junctions.

FRACTURED SOLDER RING JOINT . . . . 101




Phase II . . . . .
If that was not found to be the case . . . . . . I am suggesting audio signal tracing . . . . . . considering your capabilities and what you have that could be used to do that.
Hint . . . . .
Do you have a VCR and TV or small portable combo and a 3 ft long patch cord with RCA connectors at both of its ends and a wire leaded 0.1 ufd capacitor.
If not having small units . . . . . . could you set up radio work shop on a card table close into the "BIG" TV & VCR.

73's de Edd . . . . .

As a pre pubescent teenager, I clearly remember my first time using a condom . . . . . . I put my balls in there too .
To add further to the mind rattling nervous confusion, when I pulled down her panties , 2 fabric softener sheets fell out

.

 

[Alec_t]

IC1 looks over-cooked.

 

[Bluejets]

IC1 looks over-cooked.

Looks like some kind of varnish to me.

 

[KevM]

I have just fixed one of these Makita DMR110 radios. The display would turn on and tune to a station but there was no sound. The fault was the 1000uf 35v amplifier power supply smoothing capacitor (not the 1000uf speaker capacitors) going short circuit and that smoked the surface mount feed resistor. Replacing the capacitor and guessing at 2.2 ohms being a safe resistor replacement resulted in the radio working again.