HD AV Pack - non-working optical output

[tiertop]

My HD AV Pack is no longer outputting a working optical audio signal. The receiver acts as if nothing is connected.  The AV box is producing the red light but it is noticeably dimmer when compared to my TV's optical output. I tried  two optical cables and two XBoxes.  Inside the HD AV pack, the optical audio section is on a mini PCB and has a  tantalum cap, as shown in the photo. Could this cap be going bad and causing the LED to dim?

 

Edited April 24 by tiertop

[Bowlsnapper]

2 hours ago, tiertop said:

My HD AV Pack is no longer outputting a working optical audio signal. The receiver acts as if nothing is connected.  The AV box is producing the red light but it is noticeably dimmer when compared to my TV's optical output. I tried  two optical cables and two XBoxes.  Inside the HD AV pack, the optical audio section is on a mini PCB and has a  tantalum cap, as shown in the photo. Could this cap be going bad and causing the LED to dim?

 

Not much to replace there... There's a ceramic capacitor, but I think those rarely go bad... Maybe try replacing both that and the SPDIF LED module?

[PRince404]

Could also be a broken wire inside the cable not making it detect signal perhaps? 

[tiertop]

A few more photos.  It is so incredibly basic inside.  I had to repair the green component output years ago because the horrible molding caused a wire to eventually break. They charged $50 for this!

I don't know if I think a wire is broken.  Moving the cable around while it's operating doesn't affect anything.  Analog audio and component video are working fine.

A cap replacement is easy to find but I'm not sure how to shop for an emitter.

Edited April 24 by tiertop

[MadMartigan]

Looks like you’ve started to lose strands here. I’m assuming this is the cable that the case has ruined, as you mentioned. I don’t see anywhere else that I would personally start my troubleshooting. If you’re capable, I’d repair that connection and see what happens.

Edited April 25 by MadMartigan

[Bowlsnapper]

1 hour ago, MadMartigan said:

Looks like you’ve started to lose strands here. I’m assuming this is the cable that the case has ruined, as you mentioned. I don’t see anywhere else that I would personally start my troubleshooting. If you’re capable, I’d repair that connection and see what happens.

@tiertop Expanding upon Marty's post here, it may be possible that there is a short or something fishy about grounding that is causing attenuation/dimming in the LED or blocking the data signal from reaching the transmitter entirely. Definitely look at ALL the wiring in there.

[tiertop]

1 hour ago, Bowlsnapper said:

@tiertop Expanding upon Marty's post here, it may be possible that there is a short or something fishy about grounding that is causing attenuation/dimming in the LED or blocking the data signal from reaching the transmitter entirely. Definitely look at ALL the wiring in there.

Thanks for the tips.  I will look over it again.  It is of course possible the cabling has hidden damage too. But all the visible wiring looks ok.

The optical port is rather worn out though. It had a broken solder joint and the little door barely closes. I wonder if an electrical arc from a broken solder joint could damage it.  The port connection also has a lot of play in it.

I dug around Digikey and found a replacement emitter assembly that looks remarkably similar to the original,  and also bought a replacement cap. We'll see what happens!

[Harcroft]

That capacitor is just to smooth power goes into the SPDIF port. It has nothing to do with the actual signal itself.

Start by cleaning the AVIP cable and port connections. It's possible you have some dust causing poor contact.

Try connecting a generic high intensity red LED between the outer legs of the existing SPDIF port and directing that into your SPDIF cable. If that works but the port does not, it's the SPDIF port burning out.

Also try using the SPDIF output from the xbox to another device like a cheap Cmedia CM6206LX USB sound card or Turtle beach DSS. Try another device with SPDIF audio out to your current sound system (again cheap CM6206LX sound card is great for this).

[tiertop]

12 hours ago, Harcroft said:

That capacitor is just to smooth power goes into the SPDIF port. It has nothing to do with the actual signal itself.

Start by cleaning the AVIP cable and port connections. It's possible you have some dust causing poor contact.

Try connecting a generic high intensity red LED between the outer legs of the existing SPDIF port and directing that into your SPDIF cable. If that works but the port does not, it's the SPDIF port burning out.

Also try using the SPDIF output from the xbox to another device like a cheap Cmedia CM6206LX USB sound card or Turtle beach DSS. Try another device with SPDIF audio out to your current sound system (again cheap CM6206LX sound card is great for this).

Good ideas.  

I removed the cap from the circuit and intensity didn't change. I was wondering if it was possibly failing and becoming a short.

I will grab a toothbrush and clean up the connector.  I'm not sure why I didn't think of that.

I have a new cap and SPDIF port on the way. The SPDIF port was very worn out from decades of use anyway.  I don't have any high intensity LEDs around to experiment with unfortunately.  I do have an old PC SPDIF bracket but didn't really feel like desoldering it as that port won't fit well with the XBox adapter anyway (I have it for an old nForce MCP-D motherboard ).

Edited April 25 by tiertop

[tiertop]

So it turns out that my problem was a bad optical cable. In fact I have two bad optical cables. I suppose after all these years I finally wrapped them up too tightly or something and broke the fiber. That's why the output was dim.

I did replace the capacitor and the toslink port and they work perfectly. The original port was so worn out that the connector wobbled around in the socket and the keying was not very effective anymore.

Edited Tuesday at 01:56 AM by tiertop

[Bowlsnapper]

35 minutes ago, tiertop said:

So it turns out that my problem was a bad optical cable. In fact I have two bad optical cables. I suppose after all these years I finally wrapped them up too tightly or something and broke the fiber. That's why the output was dim.

I did replace the capacitor and the toslink port and they work perfectly. The original port was so worn out that the connector wobbled around in the socket and the keying was not very effective anymore.

Man, I am stoked to hear this. I'm happy that you got the issue fixed!