Restore Mickey Mouse!

Thread Starter

johndoe45

Joined Jan 30, 2010
364
My girlfriend has a talking mickey mouse that she wants me to try and fix.
:D

So here are the circuit boards. The voltage isn't making it to all of the connectors. but I am getting the 6 something volts from 4 C batteries from the connector and on the beginning of the board.

Any help would be appreciated. Like where to test for voltage points.
I have a copper wire soldered to ground of input connector as in bottom picture so i can alligator clip my DMM to it.
 

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hgmjr

Joined Jan 28, 2005
9,027
The presence of the bare copper wire so close to other connections has me concerned. If you have some insulating electrical tape it would be a good idea to put a small piece on the area of the board beneath the wire to avoid the possibility of a short between the bare wire and one of the exposed connections on the board.

hgmjr
 

KJ6EAD

Joined Apr 30, 2011
1,581
The first step would be careful visual inspection. Look for cold solder joints or cracks in the solder around component leads. Pay special attention to areas of the board that are subjected to mechanical stress such as the connector headers, near mounting holes and any thin sections such as that finger of board in the corner and around any large or heavy components. This board was wave soldered so the header pins are a likely spot for cold joints. Flux and reflow anything that looks questionable.
 
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Kermit2

Joined Feb 5, 2010
4,162





Looks suspicious to my eye, but pictures are hard to use for solder joint exams.
check that closely. Also consider changing out the large cap near the power pins, just for good measure. As stated by others, the problem will probably be due to solder breaks or shorts from long handling of the item.
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
i have resoldered a lot of joints.

Is an 4-7 esr high for a 3.3 uF capacitor?

Because on the chart for the Blue ESR I think it says 10+ is bad

the silver thing circled above. is it a capacitor? has no label. i fixed the wire on circled one two posts before but it is connected by a trace anyway.
 

tom66

Joined May 9, 2009
2,595
i have resoldered a lot of joints.

Is an 4-7 esr high for a 3.3 uF capacitor?

Because on the chart for the Blue ESR I think it says 10+ is bad

the silver thing circled above. is it a capacitor? has no label. i fixed the wire on circled one two posts before but it is connected by a trace anyway.
Looks like a crystal oscillator, if that is shorted to a pin then it will not oscillate so there will be no sound.
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
ok here is what i got so far. replaced some caps. resoldered some joints.

also, the red is a pnp transistor.

the number on it says

A966
O :. 7G

the black pin is 0 volts. so i think this component is bad because the Low Voltage Audio Power Amplifier LM386-1 is not getting the supply voltage (circled in white). Yellow is trace from the 0 volts to Vs of amplifier.

EDIT: However. I just removed it. Tested it with analog ohmeter. From base to emitter. one reading. Base to collector one reading. collector to emitter no reading. So it is fine. So what else could cause no voltage to the amplifier Vs???
 

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