Transport LEDs issue

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Hi all

I’ve got an issue with the row of transport LEDs - all was working correctly when I first completed my build but shortly after the bottom row, except Play, were all lit in the stopped state (see first image).

It turns out the green Play LED was blown so I replaced it today with a Blue one (no greens left over) and now the stopped state is correct, but the blue Play and white Pause LEDs won’t light when pressed. Both these LEDs are working (tested in situ with a multimeter) and all the buttons are functioning correctly, so this is only an LED issue. Video clip attached below to illustrate.

I’m a bit suspicious of the right hand as you look down (+ve, I think) leg of the Play LED as the solder is sitting poorly on the board and won’t flow through to the top even with flux paste. Feels like I may have damaged the pad.

If this is the case, would this cause the non-lighting Pause LED as well? And is there another point on the board I can jump the Play LED leg to if the pad in question has been damaged?

Many thanks!

Video Here

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Let’s see if it can be debugged.

Are all switch functions working? That would rule out an issue with the low/sink side of the matrix
Were the LEDs reinstalled with correct polarity? The anode goes into the pad with the circle, the cathode to the straight line.

The LED anodes in the bottom rows of five are connected from left to right through the circled pads; you could try to bridge them.
Likewise, the LED cathodes are connected in columns; you could try to bridge the upper/lower LEDs through the pads marked with lines.

It can also be an issue with the LED forward voltage. The current might preferentially flow elsewhere if the Vf is too high for a white LED.

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Are all switch functions working?

Yes.

Were the LEDs reinstalled with correct polarity?

Yes. And the LEDs are tested working.

The LED anodes in the bottom rows of five are connected from left to right through the circled pads; you could try to bridge them.

I’ll try this with both the Play and Pause LEDs individually and together.

It can also be an issue with the LED forward voltage. The current might preferentially flow elsewhere if the Vf is too high for a white LED.

You’re beyond my electronics knowledge here… are there any voltage readings I can take to provide any evidence for this?

FWIW, everything worked when I initially completed the build. The situation in the picture with all the transport LEDs list when in the stopped state happened on switching the seq on one time. A couple of times the LEDs would revert back to working correctly at the time, which mad em think it was a soldering issue so I reflowed everything. This morning I got round to preoiperly testing and the Play LED (a green) was blown. I’ve replaced it with a blue and now we are as per the above. One issue fixed, a new issue evident. I don’t have any insight into what blew the green Play LED in the first place.

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Andy For President.

Bridging both the Play and Pause LED anodes was the solution!

I’m sorry ( @Hawkeye ) for sullying the original design with jumper cables but I hope I’ve at least done a neat job 😅 The blue Play light is actually quite fetching…

Many thanks for the swift help, as ever.

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Very cool! It was your idea to bridge the pads 🙂
Hardly noticeable with the black wires, very clean bodge!