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Author Topic: Samson Ub7 Wireless Mic random shutting off.  (Read 424 times)

Jonathan Goodall

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Samson Ub7 Wireless Mic random shutting off.
« on: March 24, 2021, 05:12:56 am »

Hi
Longish post sorry

I am part way into a run of a musical and have run into an issue that I have not come across before.
We are using 4 Samson UB7 wireless units (Not top end stuff I know but these have performed flawlessly for multiple productions, more stable in fact than some more expensive AKG units that we have also used).
They have external aerials and I have not had drop outs with them however 2 of the 4 have randomly turned off midway into the first couple of songs. The back stage tech just had to repower them up and they were good for the rest of the show.
Each mic gets a pre show check, fresh batteries (eveready gold AA x 2) tested to be outputting no less than 3.1 volts before being placed into the pack, powered up and a line check done.
They are then powered down, closed again and taped shut so they canít pop out.
15 min before show they are placed on the talent, powered up and the lock switch engaged (this kills the power switch so it canít accidentally be powered off). Another line check is done at this point and one more just before curtain opens.
3 times now I have 2 separate units power off within 10min of the final check (one of them must have happened literally 20 sec after the final check as they said their first lines).
Each time all that had to be done was turning the pack back on and it was fine for the rest of the show.
The batteries still have plenty of charge according to the meter on the unit at the end.
I can swap out these units for another one of the same brand but I am at a loss as to what may be causing it. The hire company they come from says they have not come across the issue themselves soI am reaching out for any more ideas.
Next show is tomorrow night.

Thanks in advance.
Jonathan
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Ike Zimbel

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Re: Samson Ub7 Wireless Mic random shutting off.
« Reply #1 on: March 24, 2021, 11:42:05 am »

Hi
Longish post sorry

I am part way into a run of a musical and have run into an issue that I have not come across before.
We are using 4 Samson UB7 wireless units (Not top end stuff I know but these have performed flawlessly for multiple productions, more stable in fact than some more expensive AKG units that we have also used).
They have external aerials and I have not had drop outs with them however 2 of the 4 have randomly turned off midway into the first couple of songs. The back stage tech just had to repower them up and they were good for the rest of the show.
Each mic gets a pre show check, fresh batteries (eveready gold AA x 2) tested to be outputting no less than 3.1 volts before being placed into the pack, powered up and a line check done.
They are then powered down, closed again and taped shut so they canít pop out.
15 min before show they are placed on the talent, powered up and the lock switch engaged (this kills the power switch so it canít accidentally be powered off). Another line check is done at this point and one more just before curtain opens.
3 times now I have 2 separate units power off within 10min of the final check (one of them must have happened literally 20 sec after the final check as they said their first lines).
Each time all that had to be done was turning the pack back on and it was fine for the rest of the show.
The batteries still have plenty of charge according to the meter on the unit at the end.
I can swap out these units for another one of the same brand but I am at a loss as to what may be causing it. The hire company they come from says they have not come across the issue themselves soI am reaching out for any more ideas.
Next show is tomorrow night.

Thanks in advance.
Jonathan
A couple of things come to mind (albeit without ever having seen or used the systems in question).
1) Have you tried a bit of "shake-and-bake" to try and make the fault occur? If there are any faults in the battery contacts...cold/cracked solder joints etc. It can only take a very brief interruption of contact to turn something off, so giving a pack a good shake after it's made show-ready might tell you something. Try cupping a pack in your hands for a few minutes to simulate the heat from an actor's body for the "bake" part of the test.
2) Try cycling the power switch after you disable it. It's rare, but I have seen situations where a switch wasn't really in the position marked until it was moved there a 2nd time. In that case it was a mute switch. If the Tx was powered up with the switch in "Mute" it wasn't actually muted until the switch was cycled and the pack electronics caught the "Mute" command.
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Jonathan Goodall

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Re: Samson Ub7 Wireless Mic random shutting off.
« Reply #2 on: March 24, 2021, 02:05:17 pm »

A couple of things come to mind (albeit without ever having seen or used the systems in question).
1) Have you tried a bit of "shake-and-bake" to try and make the fault occur? If there are any faults in the battery contacts...cold/cracked solder joints etc. It can only take a very brief interruption of contact to turn something off, so giving a pack a good shake after it's made show-ready might tell you something. Try cupping a pack in your hands for a few minutes to simulate the heat from an actor's body for the "bake" part of the test.
2) Try cycling the power switch after you disable it. It's rare, but I have seen situations where a switch wasn't really in the position marked until it was moved there a 2nd time. In that case it was a mute switch. If the Tx was powered up with the switch in "Mute" it wasn't actually muted until the switch was cycled and the pack electronics caught the "Mute" command.

Thanks for the suggestions.
I have definitely tried the first one after the first time it happened. Couldnít get the issue to reproduce itself but did notice that, due the the design of the battery basket, one of the two batteries were a bit sloppy for my liking and tapping the transmitter sharply could get the battery level indicator to drop by a bar momentarily but never completely off. I have packed out that side of each basket and that stopped that happening any further.
Iíll try suggestion 2 tonight.

Cheers
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Russell Ault

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Re: Samson Ub7 Wireless Mic random shutting off.
« Reply #3 on: March 24, 2021, 04:04:23 pm »

{...}
They have external aerials and I have not had drop outs with them however 2 of the 4 have randomly turned off midway into the first couple of songs. The back stage tech just had to repower them up and they were good for the rest of the show.
Each mic gets a pre show check, fresh batteries (eveready gold AA x 2) tested to be outputting no less than 3.1 volts before being placed into the pack, powered up and a line check done.
They are then powered down, closed again and taped shut so they canít pop out.
15 min before show they are placed on the talent, powered up and the lock switch engaged (this kills the power switch so it canít accidentally be powered off). Another line check is done at this point and one more just before curtain opens.
3 times now I have 2 separate units power off within 10min of the final check (one of them must have happened literally 20 sec after the final check as they said their first lines).
Each time all that had to be done was turning the pack back on and it was fine for the rest of the show.
The batteries still have plenty of charge according to the meter on the unit at the end.
I can swap out these units for another one of the same brand but I am at a loss as to what may be causing it. The hire company they come from says they have not come across the issue themselves soI am reaching out for any more ideas.
{...}

A few more questions:
  • Why are you powering the packs down between soundcheck and the show?
  • Like Ike mentioned, are you sure the lock switch is actually working properly on those packs (i.e. have you tested that it actually locks the mute/power button)?
  • Are you doing anything to lockout the lock switch (or the gain knob, for that matter)?
  • Have you tried swapping those packs to different actors to see if the problem follows the pack?
  • How are the packs mounted on the actors?
  • Have you ruled out moisture as a potential cause?

A couple more procedural things to try:
  • IMNSHO, TXs shouldn't have power switches (or mute buttons). If I were A2 on a show and handed those TXs, the first thing I would do is turn on the lock switch, verify its operation, then tape the switch out so that it can't be thrown. Given that these are hire stock and that the switch is pretty exposed I'd also consider throwing a little deoxidizer into it and working it back and forth, just to be sure.
  • Once a TX has been powered up and tested, as an A2 the last thing I want to do is change anything; if it ain't broke, don't fix it. Powering it down to save batteries only opens the door for weirdness and mistakes, and it encourages the use of power buttons (which, as I say, shouldn't exist).
  • Battery terminals are a prime place for moisture-related corrosion (perhaps especially on down-market hire stock), and giving them a good cleaning with a deoxidizer would be high on my maintenance list at the first sign of this kind of trouble. (I know you've done a shake test, but for a lot of electronics the momentary interruption caused by vigorous shaking isn't long enough for the device's PSU capacitors to discharge to the point that the device shuts off, whereas having a battery sit "just so" for a moment on a bit of terminal corrosion will do the trick. I was A2 on a show back in 2019 where our wireless comm packs kept spontaneously rebooting (and they took a good minute to boot up), but we couldn't figure out what the problem was because they'd never reboot when shaken. One day I was talking to carpenter and out of the corner of my eye I noticed their pack reboot a moment after they'd stopped moving. Sure enough, giving the battery terminals of all the packs on the show a good clean made the problem go away overnight.)
  • You are wrapping your packs to keep out moisture, right?

-Russ
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Jonathan Goodall

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Re: Samson Ub7 Wireless Mic random shutting off.
« Reply #4 on: March 24, 2021, 06:58:31 pm »

A few more questions:
  • Why are you powering the packs down between soundcheck and the show?
  • Like Ike mentioned, are you sure the lock switch is actually working properly on those packs (i.e. have you tested that it actually locks the mute/power button)?
  • Are you doing anything to lockout the lock switch (or the gain knob, for that matter)?
  • Have you tried swapping those packs to different actors to see if the problem follows the pack?
  • How are the packs mounted on the actors?
  • Have you ruled out moisture as a potential cause?

A couple more procedural things to try:
  • IMNSHO, TXs shouldn't have power switches (or mute buttons). If I were A2 on a show and handed those TXs, the first thing I would do is turn on the lock switch, verify its operation, then tape the switch out so that it can't be thrown. Given that these are hire stock and that the switch is pretty exposed I'd also consider throwing a little deoxidizer into it and working it back and forth, just to be sure.
  • Once a TX has been powered up and tested, as an A2 the last thing I want to do is change anything; if it ain't broke, don't fix it. Powering it down to save batteries only opens the door for weirdness and mistakes, and it encourages the use of power buttons (which, as I say, shouldn't exist).
  • Battery terminals are a prime place for moisture-related corrosion (perhaps especially on down-market hire stock), and giving them a good cleaning with a deoxidizer would be high on my maintenance list at the first sign of this kind of trouble. (I know you've done a shake test, but for a lot of electronics the momentary interruption caused by vigorous shaking isn't long enough for the device's PSU capacitors to discharge to the point that the device shuts off, whereas having a battery sit "just so" for a moment on a bit of terminal corrosion will do the trick. I was A2 on a show back in 2019 where our wireless comm packs kept spontaneously rebooting (and they took a good minute to boot up), but we couldn't figure out what the problem was because they'd never reboot when shaken. One day I was talking to carpenter and out of the corner of my eye I noticed their pack reboot a moment after they'd stopped moving. Sure enough, giving the battery terminals of all the packs on the show a good clean made the problem go away overnight.)
  • You are wrapping your packs to keep out moisture, right?

-Russ

Thanks.

The initial preshow battery load and line check takes place a good hour and a half before start time hence why they are powered off after the first checks (that was the way I was taught back in the day I guess).

The actual lock switch is something I will have to investigate further, I had not noticed any issues with them not working.

The gain pot is flush oon the side and has tape covering it to prevent movement but no, the lock out switch (countersunk) has not been covered.

Due to the look the Director wanted, the transmitter is on top of all clothing and well away from the skin,  centre back.  Previously when under clothing i place them in nitrile gloves to protect against moisture however in this case they do not have such protection.
I have considered moisture as a cause but there have been no physical signs that the packs are damp, they have plenty of ventilation and as it seems to happen very early in the show before they have worked up any kind of sweat (it's 90% lit by LED so little heat from lighting) it seemed unlikely.

After the first time I did go through and clean all contacts and give the internal contacts a light buff with a fine grit emery board.

I'll have a double check of the switches tonight.

Thanks for the suggestions.
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Russell Ault

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Re: Samson Ub7 Wireless Mic random shutting off.
« Reply #5 on: March 24, 2021, 09:55:52 pm »

{...}The initial preshow battery load and line check takes place a good hour and a half before start time hence why they are powered off after the first checks (that was the way I was taught back in the day I guess). {...}

I'm not sure what the situation is there, but here the only reason we'd prep and check mics that long before top of show is if Hair & Wigs has more work than will fit into the Equity half-hour. (I've worked on at least one show where, between the Hair schedule and a very long preshow fight call, my first mics had to be delivered 1.5h before curtain; mercifully those are exceptions, although I'm sure the actors appreciated the extra on the their paycheque.)

If you're not mic'ing actors until 15 minutes before curtain, do you need to be running mic checks that early? (Heck, do you even need to be at the venue that early?) To be clear, I'm not sure this is necessarily contributing to the issues you're having (although I suppose it might be if the packs have some weird fault that shuts them off X amount of time after being powered up for the first time, which seems unlikely but isn't strictly speaking impossible), but for me once a mic has been tested I want as little to happen to it as possible.

-Russ
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Jonathan Goodall

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Re: Samson Ub7 Wireless Mic random shutting off.
« Reply #6 on: March 24, 2021, 10:44:04 pm »

I'm not sure what the situation is there, but here the only reason we'd prep and check mics that long before top of show is if Hair & Wigs has more work than will fit into the Equity half-hour. (I've worked on at least one show where, between the Hair schedule and a very long preshow fight call, my first mics had to be delivered 1.5h before curtain; mercifully those are exceptions, although I'm sure the actors appreciated the extra on the their paycheque.)

If you're not mic'ing actors until 15 minutes before curtain, do you need to be running mic checks that early? (Heck, do you even need to be at the venue that early?) To be clear, I'm not sure this is necessarily contributing to the issues you're having (although I suppose it might be if the packs have some weird fault that shuts them off X amount of time after being powered up for the first time, which seems unlikely but isn't strictly speaking impossible), but for me once a mic has been tested I want as little to happen to it as possible.

-Russ

Yip hair on this one takes an age.
Also I am the only dedicated Audio person in the show so I have to check and prep and do everything from the band to fitting the microphones to the talent. One of the stagehands has acted as the on-the-spot person when it hit the fan.
« Last Edit: March 24, 2021, 10:48:24 pm by Jonathan Goodall »
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Jonathan Goodall

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Re: Samson Ub7 Wireless Mic random shutting off. UPDATE
« Reply #7 on: March 29, 2021, 03:22:46 am »

Yip hair on this one takes an age.
Also I am the only dedicated Audio person in the show so I have to check and prep and do everything from the band to fitting the microphones to the talent. One of the stagehands has acted as the on-the-spot person when it hit the fan.

Update.

Ended up swapping out the problematic unit with another one and finished off the last few shows with no further issues.

Thanks for all the suggestions.

Cheers
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ProSoundWeb Community

Re: Samson Ub7 Wireless Mic random shutting off. UPDATE
¬ę Reply #7 on: March 29, 2021, 03:22:46 am ¬Ľ


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