No headphone output from electronic drum kit, should I replace capacitors but which ones?

Thread Starter

Bassquake

Joined Feb 16, 2018
41
I have a Session Pro DD505 electronic drum kit which no longer has sound coming out of headphone jack. The Line Out Left and Right outputs are fine though.

I replaced the headphone socket to rule out a connection issue.

I suspect its the caps as it worked for a while, then the sound started "blipping" and failing, and now no sound. They all look fine. But am not sure which ones to replace. Maybe the bottom 6?

I've attached some photos of the device.

Help appreciated.
 

Attachments

Thread Starter

Bassquake

Joined Feb 16, 2018
41
I've never tested ICs before but looking at some tutorials, I did the following:

  1. Device is off.
  2. Set multimeter in Diode mode
  3. Put black on pin 4 (bottom right of chip as its ground apparently)
  4. Then red on all pins and jot down multimeter values. Results shown in image attached.

Let me know if need to test differently. Thanks.
 

Attachments

Thread Starter

Bassquake

Joined Feb 16, 2018
41
Ok, I think I found the issue. After poking around some more (literally!), I found if I pushed using plastic tweezers on the black resistor (I assume its a resistor) marked on the photo below, the sound would return!

So I thought I'd resolder its joints if its a cold join but it immediately broke which tells me the resistor was already damaged. One of the sides contacts came clean off.

I assume its a resistor so hoping you guys can tell me. And how can I find out its value as I can't get a reading on it.

Edit: Looking at the text box next to those smds it looks like its L3 (attached pic). Is that a diode?
 

Attachments

Last edited:

MrChips

Joined Oct 2, 2009
21,869
A component with identifier L3 would be an inductor, not a resistor.
Turn the power on and measure the DC voltage at the L3 left side pad with respect to ground.
Then do the same with L3 right side pad.

Do the same with L1 and L2.
 

Thread Starter

Bassquake

Joined Feb 16, 2018
41
I get no measurements on L3 right side, on the left it flits around 0.03 - 0.04.

For L2 and L1 its flits between 0.45 and 0.46 on both sides for those.

Multimeter is set at 20.
 

Thread Starter

Bassquake

Joined Feb 16, 2018
41
Unfortunately I had a mono headphone on when poking around. I tried pressing the other smds but still no Left channel. I do hear a slight blip on the Left channel whenever I jump L3 if that means anything.
 

Thread Starter

Bassquake

Joined Feb 16, 2018
41
Do you have another amplifier to hand for poking at the inputs and outputs of the chip?
Not sure what you mean. Do you mean connect the output of the TDA1308 chip to an amp? If so, I assume from the spec sheet its pin 1 and gnd would be the Left channel?

No sound on the LEFT channel could be a completely different problem.
Yeh its a pain, I fix one issue and there's still another!
 
Top