Potential Component damage if using long TRRS plugs.

[Mr-JimmyDeath]

Hello.

Awesome project, I keep getting asked to build these for people so have made a few now.

Whilst building/testing the E1 version I have spotted a potential issue regarding the TRRS connectors. I have found some TRRS plugs that are long enough that when fully inserted will project beyond the end of the PJ-322 socket (J12) and break diodes D11, D15. I have mitigated this issue by fitting SMD diodes under the PCB.

Suggest moving D11, D15 away from back of socket (or using SMD parts).

To a lesser extent this could affect J15 if accidentally plugged in there, so you could also consider moving R47 & C51.

Thanks, Regards

James

[UzixLS]

Hello.
Thanks for report.
Could you take a photo with inserted long TRRS plug?

[Mr-JimmyDeath]

Hello.

Pictures attached are:

1. Comparison with standard 3.5mm Stereo plug
2. Plug fully inserted into socket and projecting beyond. Clearly it won't work like this.
3. My temp solution of SMD Diodes underneath

Regards
James

[UzixLS]

Thanks for detailed photos. I've never seen so long plugs in wild.
Isn't mounted THT diodes would be strong enough to prevent long plug insertion?

[Mr-JimmyDeath]

Hi.

I was using glass 1N4148 diodes, one broke as soon as I inserted the plug. I did consider mounting them with the lead closest to the socket but then then you would need to insulate the leads to prevent them shorting to the plug which seemed a lot more effort than mounting some underneath.

Regards

James

[UzixLS]

Accepted, will be fixed in next revision.

[andykarpov]

BTW, what's the profit to insert a TRRS plug into the normal TRS socket?

[Mr-JimmyDeath]

There isn't if you are using D1 and earlier boards however, the E1 boards uses TRRS sockets, socket J12 will give you audio L & R plus composite video.