Modifying The Uniden BC23A (Auto Power Off)

[JASII]

With so many Uniden owners using amplified external speakers, I have wondered if anybody here has modified the Uniden BC23A amplified external speaker? I love the speaker, but I don't care for the Auto Power Off function. I sometimes miss a little bit of audio while the speaker "wakes up". Does anybody know how difficult it would be to remove that functionality?



Uniden Accessories: Bearcat 15-Watt External Speaker

 

[k1xd]

I have a BC23A Speaker connected to a Uniden Homepatrol Scanner. Seems like the first word or two gets clipped off by the 'auto power on' feature of the speaker.

I modified my speaker to stay on all the time. Basically, if you take apart the speaker and trace out the circuit, the on-time is controlled by a 220uf capacitor, C7. C7 is charged up by incoming audio (358 op amp and diode on output side to C7) and discharged through a 82K resistor to ground. I put in a pull-up resistor, 10k ohm from the plus side of C7 to Vcc on the 358 amp and the speaker stays on... no clipped words. What this does is to hold C7 above the threshold to switch the speaker off.

I'll post a picture of the mod this weekend...

 

[ranchboy]

Please post! Who in there right mind would design a scanner speaker like this? It's totally useless with the auto shutoff feature! The first two seconds are usually the most important part of the transmission!
Thanks

 

[JASII]

I am also hoping that you can post more information on this.

 

[k1xd]

Will post info this weekend!
I've got a second one to modify.

 

[W8WCA]

I just rec'd one of these BC23A speakers (I ordered thru Amazon from pcrush-outlet) - and it has a Volume Control WITH On/Off in it on the side.

So maybe Uniden has recently changed them?

The Manual even mentions it is volume and power switch.

I see WalMart still has them and I could have saved a few$ too!
http://www.walmart.com/ip/Uniden-BC...ereo-Plug-for-Scanner-and-CB-Compact/22153733

That Photo shows the Volume Control too.

 

[W8WCA]

Ok installed and even though it has power switch. It has power savings. The light goes out after only 20 or so seconds of quite air time

Sent from my SM-N910T using Tapatalk

 

[W8WCA]

I have a BC23A Speaker connected to a Uniden Homepatrol Scanner. Seems like the first word or two gets clipped off by the 'auto power on' feature of the speaker.

I modified my speaker to stay on all the time. Basically, if you take apart the speaker and trace out the circuit, the on-time is controlled by a 220uf capacitor, C7. C7 is charged up by incoming audio (358 op amp and diode on output side to C7) and discharged through a 82K resistor to ground. I put in a pull-up resistor, 10k ohm from the plus side of C7 to Vcc on the 358 amp and the speaker stays on... no clipped words. What this does is to hold C7 above the threshold to switch the speaker off.

I'll post a picture of the mod this weekend...

I will give this a try this weekend.

If no Photo's posted by then I will post a couple

Tkx @k1xd

 

[bill31089]

Does anyone have pictures of this I'm a little confused about this

 

[k1xd]

Modifying The Uniden BC23A Speaker ( Auto Power Off Disable )

Do this MOD at your own risk....

1. Remove the four screws securing the rear housing.
2. Remove the three screws securing the PCB
3. Remove the PCB and orient solder side up.
4. Attach 10k resistor.

Auto Power OFF will be disabled... Amplifier is always ON.

 

[SergioLopez]

I do make the mod and still working, following the recommendations of k1xd.

 

[n4srv]

Are you saying that this mod worked for you? I am getting ready order this speaker and need to know if I should order some resistors, what watt did you use?

 

[slicerwizard]

Use the smallest wattage you can find. 1/8W is fine.

 

[n4srv]

Thank You for the fast reply!

 

[elrod]

Not trying to hijack this thread but has anyone come up with a way to disable the auto shut off on a radio shack 21-541A speaker? I know there was a thread in here somewhere that I can't seem to find now.
I also remember that someone had said that the mod was for a different model rs speaker.
Anyone?

Chuck

 

[DAThomson]

BC23a- ongoing, schematic?

I know this thread is a zombie now, but am curious if anyone ever found a schematic for this unit- I would like to build into it the ability to input from multiple radios and it looks like it would be easy enough, but some of the SMD components (resistors) are not designated and I would like to be able to match the impedance with the additional inputs by inserting closer to the op-amp instead of just cascading another matching transformer at that point...

 

[J20]

Thanks to the diagrams and info on this speaker mod jist did it to one today. Seems to work well

73s

 

[0BRETT]

Any long term issues identified with this mod at all? I'm about to do it myself. I use this speaker in the car and miss too much initial audio on transmissions.

Im going to also install a DC and audio socket so I can remove the speaker from it's installed location if necessary and use it inside my house.

 

[voyger522]

Modifying The Uniden BC23A Speaker ( Auto Power Off Disable )

Do this MOD at your own risk....

1. Remove the four screws securing the rear housing.
2. Remove the three screws securing the PCB
3. Remove the PCB and orient solder side up.
4. Attach 10k resistor.

Auto Power OFF will be disabled... Amplifier is always ON.

I tried this.but my speaker shuts down after awhile & red light goes out.if I unplug the power for a short time it will come back on ut goes out again.any ideas? I got four I want to do.

 

[voyger522]

I tried this.but my speaker shuts down after awhile & red light goes out.if I unplug the power for a short time it will come back on ut goes out again.any ideas? I got four I want to do.

I remover the resistor.speaker works as designed again.i figured the resistor has the wrong value.i ordered resistiors like the one in the photo.