Lightspeed Mic connection issue

LDJones

LDJones

Touchdown! Greaser!
Gone West
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Jonesy
Last night I settled into the CRJ for a night flight from MSP-LAN and plugged my Lightspeed Zulu.2 into the comm jacks. But no matter what we tried, I couldn't get the mic to work. We tried everything, reconnecting, cleaning, etc. Headphones were fine, just no mic connection. Finally, we decided to head out without headsets which is a bit of a pain.

Once en route I asked the captain to try my headset on her side. She did and it worked just fine. I plugged in her classic DC clamps into my side and they worked just fine.

I've flown with these headsets in several dozen different CRJs and dozens of GA aircraft and have NEVER had an issue ever.

Any speculation as to the culprit?
 
Mic sensitivity possibly set too low on the headset to break the squelch setting in the right seat on the com panel in that plane?

There is a mic sensitivity micro screwdriver level under the windscreen.

Did you switch back then try your Lighspeeds in the right seat after you got the DC's to work? Could have also been a internal contact on the panel that was not making contact initially.
 
From what you're describing Jonesy, you make the statement that "no matter what we tried" - you appear to have done the basic troubleshooting already. So I'll surpass the squelch, and contact point failure.

Also, since you used another headset that worked, I'm going to suggest two items to try:

1) Check the smaller PJ-068 (smaller connection) mic plug on your headset. Make sure that it is not bent at any of the conductor zones (between black bands). If it is bent, I would not recommend attempting to bend it back unless you are confident in success. You would need to have either me or Lightspeed replace that connection.

2) Since you said they worked in other similar RJ's I don't think there is an AC crossfeed problem that those headsets sometimes have. Having said that, there may be a low power issue on the co-pilot jack that is not delivering enough current for the mic bias. So while it would be enough power for the 1980's DC mic, there's not enough for the slightly more advanced cardioid mic. This problem would be a maintenance issue to bring up for the A&P to check for dirty or low power current to the jack.

9 times out of 10 it ends up being something simple, but those are 2 options if you've already tackled the other tests.
 
Shawn said:
Mic sensitivity possibly set too low on the headset to break the squelch setting in the right seat on the com panel in that plane?

There is a mic sensitivity micro screwdriver level under the windscreen.

Did you switch back then try your Lighspeeds in the right seat after you got the DC's to work? Could have also been a internal contact on the panel that was not making contact initially.
Click to expand...

We swapped planes for the return flight this morning so didn't get to retry it. Where's the sensitivity adjustment?
 
Archammer said:
From what you're describing Jonesy, you make the statement that "no matter what we tried" - you appear to have done the basic troubleshooting already. So I'll surpass the squelch, and contact point failure.

Also, since you used another headset that worked, I'm going to suggest two items to try:

1) Check the smaller PJ-068 (smaller connection) mic plug on your headset. Make sure that it is not bent at any of the conductor zones (between black bands). If it is bent, I would not recommend attempting to bend it back unless you are confident in success. You would need to have either me or Lightspeed replace that connection.

2) Since you said they worked in other similar RJ's I don't think there is an AC crossfeed problem that those headsets sometimes have. Having said that, there may be a low power issue on the co-pilot jack that is not delivering enough current for the mic bias. So while it would be enough power for the 1980's DC mic, there's not enough for the slightly more advanced cardioid mic. This problem would be a maintenance issue to bring up for the A&P to check for dirty or low power current to the jack.

9 times out of 10 it ends up being something simple, but those are 2 options if you've already tackled the other tests.
Click to expand...

Thanks for the insights. Who knows if/when I'll get that plane again. Hopefully others will experience it and get a chance to write it up for MX.
 
LDJones said:
We swapped planes for the return flight this morning so didn't get to retry it. Where's the sensitivity adjustment?
Click to expand...

If you find that adjustment is necessary after other tests, there is a little round cap right in the middle of the 4 case screws on the mic bell. *This cap likes to pop off and get lost VERY easily so be extremely careful. User your fingernail and it should come out fairly easily.

You can adjust the very small white flat-head screw (gain adjustment potentiometer) depressed inside. Be very careful and adjust only 1/4 turns between tests.

Clockwise a quarter is more sensitive (higher gain)
Anticlockwise a quarter is less sensitive (lower gain)
 
Last edited:
Archammer said:
If you find that adjustment is necessary after other tests, there is a little round cap right in the middle of the 4 case screws on the mic bell. *This cap likes to pop off and get lost VERY easily so be extremely careful. User your fingernail and it should come out fairly easily.

You can adjust the very small white flat-head screw (gain adjustment potentiometer) depressed inside. Be very careful and adjust only 1/4 turns between tests.

Clockwise a quarter is more sensitive (higher gain)
Anticlockwise a quarter is less sensitive (lower gain)
Click to expand...

Thanks for the tip.
 
LDJones said:
Thanks for the insights. Who knows if/when I'll get that plane again. Hopefully others will experience it and get a chance to write it up for MX.
Click to expand...
Did you write it up?
 
The Lightspeeds also have internal dip switch settings for various wiring configurations. Could be that com panel did not like the current configuration.
 
...also just call Lightspeed tech support. They are super helpful and I am sure they have heard it all and may have an answer for ya.

800-332-2421
 
Shawn said:
...also just call Lightspeed tech support. They are super helpful and I am sure they have heard it all and may have an answer for ya.

800-332-2421
Click to expand...

I will do that tomorrow.
 
Shawn said:
...also just call Lightspeed tech support. They are super helpful and I am sure they have heard it all and may have an answer for ya.

800-332-2421
Click to expand...

I did talk to Lightspeed today and they said it's likely a problem with the grounding of the mic jack on that side of that particular aircraft and probably only manifest itself with an ANR headset. She told my I could flip the two mic bias switches inside the batter box to OFF and it would probably work, at the cost of some Bluetooth mic audio quality when NOT connected to a wired audio connection.

Good to know!

Loren
 
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