Need help finding a short!

Thread Starter

S70 Garage

Joined Jan 28, 2019
10
So i am working on adding an aux and bluetooth to my 1999 Volvo S70 T5m, with the stock radio and everything was going fine, all but one solder point was good, when the bluetooth controller(from a pair of wireless headphones) randomly stopped working and had a short. Not sure how since i left for 10 minutes to eat and didnt mess with it, but i came back and it just quit. And its going to be because of something stupid too, because its always my luck, but i cant seem to figure it out leaving me very frustrated.
 

wayneh

Joined Sep 9, 2010
16,114
ok, hmmmmmm. I just dont understa d why the board would randomly start shorting for no reason, though.
Well I haven’t seen anything yet to convince us that there is a short. All sorts of things could prevent the system from working. Sounds to me like it simply lost the connection and failed to pick it back up. My advice: Turn it off and back on again.
 

Thread Starter

S70 Garage

Joined Jan 28, 2019
10
Well I haven’t seen anything yet to convince us that there is a short. All sorts of things could prevent the system from working. Sounds to me like it simply lost the connection and failed to pick it back up. My advice: Turn it off and back on again.
Well, i have tried turning it on and off plugging it into usb and unplugging. Here is a picture, would like to have posted a video but it did not seem to let me. When it was working, the voltmeter wouldnt beep when placing the black onr to any ground.
 

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MrChips

Joined Oct 2, 2009
19,421
I am not convinced that it is a short.

A DMM "beeps" while doing a continuity test when the resistance detected is below a certain threshold.
Audio amplifier outputs are designed to have low impedance outputs. We do not know what is the output impedance of your bluetooth headphone amplifier.

The symptom in your situation is the device is not working. The cause can be anything.
Maybe it is not powered correctly.
Maybe it is not paired correctly.

Tell us more about what you were trying to do.
Where are your connections?
Show us more photos of the entire device and the other device.
 

Thread Starter

S70 Garage

Joined Jan 28, 2019
10
I am not convinced that it is a short.

A DMM "beeps" while doing a continuity test when the resistance detected is below a certain threshold.
Audio amplifier outputs are designed to have low impedance outputs. We do not know what is the output impedance of your bluetooth headphone amplifier.

The symptom in your situation is the device is not working. The cause can be anything.
Maybe it is not powered correctly.
Maybe it is not paired correctly.

Tell us more about what you were trying to do.
Where are your connections?
Show us more photos of the entire device and the other device.
So, what i am doing it adding an aux/bluetooth to my car. I had a pair of wireless headphones and took the board out of it. On the board, there is a Right+, Right-, Left+, and Left-. Right. So obviously, i found the Left and Right channels on the Casette player board in the radio. I soldered a wire to the right channel to the radio and that went to Right+ on the bluetooth controller. And left channel went to Left+, obviously. And Right- and Left - are the same thing so those went from the bluetooth controller to the gnd on the radio. Will add pictures too.
 

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wayneh

Joined Sep 9, 2010
16,114
After reading your latest post, I’d also test the connections into your system. Try another source such as the headphone signal from a phone, or just touch the wires and see if you can hear it.
 

Thread Starter

S70 Garage

Joined Jan 28, 2019
10
After reading your latest post, I’d also test the connections into your system. Try another source such as the headphone signal from a phone, or just touch the wires and see if you can hear it.
Right now nothing is connected, it is a bare board, and sometimes it will turn on and connect but it is still lighting up red saying there is a short. But it sometimes will turn on and connect.
 

Alec_t

Joined Sep 17, 2013
10,467
would like to have posted a video but it did not seem to let me.
How will a video of something not working be helpful?
Right now nothing is connected, it is a bare board, and sometimes it will turn on and connect
How can a bare board turn on? :confused:
What supply voltage does the board now have? The car system is 12V, but when the board was in the headphones wouldn't it have had a much lower supply voltage?
 
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Thread Starter

S70 Garage

Joined Jan 28, 2019
10
The bluetooth board has an LED indicator for shorts? That's surprising.
It is the charging light but it also reacting to a short.
How will a video of something not working be helpful?

How can a bare board turn on? :confused:
Well, if i plug it into usb without having the speaker wires attached to the board, my bad. But for a video, to show what i am doing and why i believe there is a short, with all the speaker teminals grounding to each other and whatnot(explained in a past post).
 

Thread Starter

S70 Garage

Joined Jan 28, 2019
10
How will a video of something not working be helpful?

How can a bare board turn on? :confused:
What supply voltage does the board now have? The car system is 12V, but when the board was in the headphones wouldn't it have had a much lower supply voltage?
Oh, and the batter was 3.7v, but i have it using usb that it charges with and removed the battery.
 
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