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Low Volume

avcat

Member
Apr 27, 2005
16
0
11
West Virginia
When the Volume on my RCI 2950DX is set to max the audio
sounds like its set at about at about one third. Can't hardly
hear it.

Any suggestions?

Thanks

Avcat
 

I have heard a few complaints about that problem. Some of them will have no receiver audio at all.

The culprit usually turns out to be a transistor that completes the ground circuit to the internal speaker AND the external speaker jack, both.

If you won't be using the PA function, simply shorting across it will probably take care of the problem. The callout number is Q73, and it's located immediately to the front of the external speaker jack.

It's a surface-mount part, like nearly everything in that model. Not a project for a beginner.

Somebody should shoot a couple of pics of this one. Gotta figure there's a place to put a jumper wire that wouldn't risk damaging the other nearby parts. Haven't run into one of those first-hand, yet.

73
 
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My 2950DX

I see this is a old post, but my 2950DX volume is now starting to fade away? what was the out come of that jumper? what should I short across from the ground? any Pics? this surface mount is a pain in the butt! Is there a simple fix?

thanks for any info!
 
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I see this is a old post, but my 2950DX volume is now starting to fade away? what was the out come of that jumper? what should I short across from the ground? any Pics? this surface mount is a pain in the butt! Is there a simple fix?

thanks for any info!

If the transistor "Q73" is your problem then the jumper will most certainly fix your problem, but be aware that you will not like the outcome if you intend to use the "PA" function.
If you are careful you can just temporarily jumper the transistor just to see if that is your problem.
Then, if that is the problem, and you want to fix it properly you can find out the device number or part for Q73 and secure a proper replacement.
Once you have the proper part you have part of the problem fixed.
The rest of the problem is removing the offending part and installing the replacement part without damaging it or the radio.
Surface mount component replacement is not for the inexperienced or the timid.
 
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You got that right. There have been many SMT 2950's destroyed by truck stop shops "trying" to install a good buddy echo board.
 
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Hell Just use a echo mic, I have a SA 117. works ok I guess, But yea I already ordered the TN2510 ? I think it was? Q73.. now I can solder pretty small stuff. I have the correct tools to do it, OK,? where do I cross the transister gate draw or where? I am not understaning where to short the pa? and or test cross the transistor?

Thanks

I also ordered a new audio chip Common one!
 
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Any Help? where do I jump the Q73 to test it, and where do I jump through pa?

Find connector or header pin labeled 'J2' and take a small jumper wire and touch it to the center pin of 'J2' and the other end of the wire to circuit board ground.
Be careful and make certain that what you think you are doing is actually what you intend to do.
If your volume does not come back or get louder then Q73 is not your problem.
 
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gee I cant find J2 for the life of me?

Sometimes things are hard to find.

This might be of some help; J3 is the speaker connector.
And it is possible that J2 might be near it.

But, if you can't find J2, but you can find J3, then follow one of the traces from J3 and if it goes to the external speaker jack the go back to J3 and put your jumper test wre on the other pin of J3.( the one that does not go to the external speaker jack)
If Q73 is, or other components associated with Q73, the problem then your volume should go up when you jumper this pin to ground.

Alternately you can (with volume turned not turned up very high you can mementarily touch one of the terminals on the speaker itself with the grounded wire ( but only momentarily as to avoid causing the audio output ic to become damaged) and if the volume goes down then touch the wire to the other speaker terminal and if the volume goes up then Q73 or associated circuitry is most likely the problem. (if the volume goes up in this case then it is not unsafe to keep the wire in contact with this pin for as long as you need to convince yourself that this is conclusive )
 
OK, I think I did this correct to lead to No differance in it? any one think it could be a weak TA7222? Audio chip?




Sometimes things are hard to find.

This might be of some help; J3 is the speaker connector.
And it is possible that J2 might be near it.

But, if you can't find J2, but you can find J3, then follow one of the traces from J3 and if it goes to the external speaker jack the go back to J3 and put your jumper test wre on the other pin of J3.( the one that does not go to the external speaker jack)
If Q73 is, or other components associated with Q73, the problem then your volume should go up when you jumper this pin to ground.

Alternately you can (with volume turned not turned up very high you can mementarily touch one of the terminals on the speaker itself with the grounded wire ( but only momentarily as to avoid causing the audio output ic to become damaged) and if the volume goes down then touch the wire to the other speaker terminal and if the volume goes up then Q73 or associated circuitry is most likely the problem. (if the volume goes up in this case then it is not unsafe to keep the wire in contact with this pin for as long as you need to convince yourself that this is conclusive )
 
OK, I got louder Volume big time,, I pulled the external speaker plug out a little and held a probe there on speaker ground, then took the other end to chassie, WOW IT GOT LOUDER! But bad sueal out of speaker with that jumped! so could it be that ity bity transistor Q73?


Thanks all for info
 
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OK, I got louder Volume big time,, I pulled the external speaker plug out a little and held a probe there on speaker ground, then took the other end to chassie, WOW IT GOT LOUDER! so could it be that ity bity transistor?


Thanks all for info

The chassis is not always ground.
It could be Q73.

CR4 - Thread: BST-80 FET NXP replacement?
http://www.supertex.com/pdf/datasheets/TN2510.pdf

Mouser Electronics
DIGI-KEY
Are a couple of places, but there are many others that will sell you these types of parts.
If you scrounge enough electronics from the dumpers you will find something with a mosfet that will do the job, but you could aslo order the correct part from someplace...... should be very inexpensive..... S&H will cost more than the part.
Maybe someone on the forum might do you a favor and put one in an envelope and mail it to you. (just a thought)
I would if I had one handy.

It looks to me like you could stack one on top of the other and increase the current handling by decreasing Rds (on)

Remember, if you don't have the skill for this type of work, it could be very easy to damage the new part or the pcb.(or both)

If you attempt this and make it all the way through, then inspect the pcb board after you are done to make sure that there is no errant solder any where else on the board that might have fallen from the tip of the soldering iron.(could short something out and cause it to not function correctly or damage other components when the radio is then powered up)
 
OK thanks, I found the TN2510, on ebay but it is (TN2510N8 -TRANSISTOR,N-CHANNEL DMOS FET,100V,3A,1.5 OHM RDS #230845298143)

I have a very pointy solder station. Hell when I got it, the book said it was great for SMT. . to make it easier to get to, I just need to unsolder the power plug to get out of the way, also never fount J2? MIA!

Thanks


The chassis is not always ground.
It could be Q73.

CR4 - Thread: BST-80 FET NXP replacement?
http://www.supertex.com/pdf/datasheets/TN2510.pdf

Mouser Electronics
DIGI-KEY
Are a couple of places, but there are many others that will sell you these types of parts.
If you scrounge enough electronics from the dumpers you will find something with a mosfet that will do the job, but you could aslo order the correct part from someplace...... should be very inexpensive..... S&H will cost more than the part.
Maybe someone on the forum might do you a favor and put one in an envelope and mail it to you. (just a thought)
I would if I had one handy.

It looks to me like you could stack one on top of the other and increase the current handling by decreasing Rds (on)

Remember, if you don't have the skill for this type of work, it could be very easy to damage the new part or the pcb.(or both)

If you attempt this and make it all the way through, then inspect the pcb board after you are done to make sure that there is no errant solder any where else on the board that might have fallen from the tip of the soldering iron.(could short something out and cause it to not function correctly or damage other components when the radio is then powered up)
 

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