I have a DX 959 Galaxy with a manu date of 2010 and has no sound. It will transmit with good modulation but no sound from the main speaker or external and when switched to PA it won't make a sound either?? I checked for any bad connections nothing found.
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959 DX GALAXY-NO SOUND
- Thread starter hammer0630
- Start date
first question is whether or not the S meter in the radio is showing it receiving signals or not.
if it is, then it sounds like a bad audio chip. there are more possibilities than that, but IC chips do go bad.
a quick test you can do is to turn the volume on the radio all the way up, and touch your finger to pin 4 of the audio chip. (IC 8 located on the right side of the radio with the component side up and the knobs facing you)
http://www.cbtricks.com/radios/galaxy/dx959_mosfet/graphics/dx959_mosfet_sch.pdf
if the audio chip is still good, you should get a hum from the speaker with your finger on pin 4. (pin 1 is closest to the front of the radio, and yes, your finger will be too big to just touch pin 4. dont worry about touching the other pins)
if you dont get the hum then the next step is to measure the voltages on each pin of the audio IC. checking them against the service manual found here:http://www.cbtricks.com/radios/galaxy/dx959/graphics/dx959_serv_manual.pdf
if the voltages you measure are significantly different than the voltages that the service manual shows, then you can be pretty sure the audio chip is bad and just replace it.
be sure to read up on the proper way to replace a chip like this.
heat sink compound, isolated from the chassis and such.
good luck,
LC
if it is, then it sounds like a bad audio chip. there are more possibilities than that, but IC chips do go bad.
a quick test you can do is to turn the volume on the radio all the way up, and touch your finger to pin 4 of the audio chip. (IC 8 located on the right side of the radio with the component side up and the knobs facing you)
http://www.cbtricks.com/radios/galaxy/dx959_mosfet/graphics/dx959_mosfet_sch.pdf
if the audio chip is still good, you should get a hum from the speaker with your finger on pin 4. (pin 1 is closest to the front of the radio, and yes, your finger will be too big to just touch pin 4. dont worry about touching the other pins)
if you dont get the hum then the next step is to measure the voltages on each pin of the audio IC. checking them against the service manual found here:http://www.cbtricks.com/radios/galaxy/dx959/graphics/dx959_serv_manual.pdf
if the voltages you measure are significantly different than the voltages that the service manual shows, then you can be pretty sure the audio chip is bad and just replace it.
be sure to read up on the proper way to replace a chip like this.
heat sink compound, isolated from the chassis and such.
good luck,
LC
Hopefully someone can answer your question, which will help me with the same problem. I have an old Vintage Realistic TRC 55 with the same problem. PM if you get the solution, Good luck and 3's to ya,
555
555
Thanks for the good info! (I can't remember now if I tried a different mic so I will try again thanks 9C1Driver.) I am not at all good under the hood of a radio but what I thought was very strange is that it transmits aprox 4 watts and swings forward/audio and sounds good when monitoring on a different CB and receives a signal also as I transmitted from a handheld with and with out a antenna "to reduce transmit power" and positioned it in different areas and the Galaxy meter showed the different signal strengths.
certainly does sound like a bad audio chip.
do the tests i laid out in my last post, and let us know what you come up with.
if it does turn out to be a bad audio chip, we can definitely walk you through its replacement.
you will need a soldering pencil, some heatsink compound, and either a de-soldering bulb or some de-soldering braid.
all can be found at your local radio shack.
(if you are not too experienced at soldering, i would suggest the bulb, as radio shacks braid can be a bit hard to work with. IE-its not the best brand out there)
the chip can be found on ebay.
TA7222AP
Toshiba TA7222P Integrated Circuit Sipp | eBay
LC
do the tests i laid out in my last post, and let us know what you come up with.
if it does turn out to be a bad audio chip, we can definitely walk you through its replacement.
you will need a soldering pencil, some heatsink compound, and either a de-soldering bulb or some de-soldering braid.
all can be found at your local radio shack.
(if you are not too experienced at soldering, i would suggest the bulb, as radio shacks braid can be a bit hard to work with. IE-its not the best brand out there)
the chip can be found on ebay.
TA7222AP
Toshiba TA7222P Integrated Circuit Sipp | eBay
LC
I'm now in this same situation but with a galaxy 939. I receive the radio a couple of months back and just now getting time to take it out and put it to work.
Brand new I broke the original plastic on it and has a build date of 2008.
Fired it up, modulates well and sounds great on the receive radio across the shack. Went to do a receiver test and nothing..... The meter gives an s9 just where it should but no sound. Tried PA and nothing, talkback nothing.
Undressed the chassis, the board and all the joints look best I've seen in a galaxy in several years. Prodded about, touched up solder around the audio ic, regulator and towards the rear around the speaker/PA Jack's. Got nothing. Called it a night in the shack and came in to find this thread. Will do some more troubleshooting tomorrow.
Brand new I broke the original plastic on it and has a build date of 2008.
Fired it up, modulates well and sounds great on the receive radio across the shack. Went to do a receiver test and nothing..... The meter gives an s9 just where it should but no sound. Tried PA and nothing, talkback nothing.
Undressed the chassis, the board and all the joints look best I've seen in a galaxy in several years. Prodded about, touched up solder around the audio ic, regulator and towards the rear around the speaker/PA Jack's. Got nothing. Called it a night in the shack and came in to find this thread. Will do some more troubleshooting tomorrow.
Well fellas, I need some help. What voltages should I be seeing on the IC8(tda2003) audio amplifier?
In rx ic8
1- 1.26
2- .85
3-gnd
4- 6.22
5- 13.47
Q37
1- 12.69
2- 8.65
3- 13.38
With the volume knob up, squelch all the way down, rf gain all the way up, nb/anl off I should be getting something on the speaker jack but not getting anything.
Just doing some quick readings but will be getting the schematic up on the PC here shortly to see the direction to go
In rx ic8
1- 1.26
2- .85
3-gnd
4- 6.22
5- 13.47
Q37
1- 12.69
2- 8.65
3- 13.38
With the volume knob up, squelch all the way down, rf gain all the way up, nb/anl off I should be getting something on the speaker jack but not getting anything.
Just doing some quick readings but will be getting the schematic up on the PC here shortly to see the direction to go
Ok, did you put in an external Speaker in the Speaker jack?
Why?
Do you hear a thunk from the speaker when you power up? If so -Then a brand-new Audio Chip isn't the first thing on your list - but if you don't hear ANYTHING - then suspect speaker wiring more than the Audio Chip - push the chip down a few steps in your "gotta' do-this list"
If you hear a Thunk - check Squelch - see if that pot is dirty or can even set background hiss - pop noise from the open and closing of Squelch when you operate the control.
Ok, still no?
Then check to see if the EXT SP jacks switch contacts are "stuck" open - making no contact - it's the first thing the Audio Amp routes to past the CB/PA switch. This test is only for EXT Speaker - there is a common at the CB/PA/RB for the Speaker - which is also for PA - those route thru J18 from the front panel back to the main board - where it's common ground.
So, another test would be to simply jumper the "black wire" from the Speaker (-) terminal back to any foil ground and see if you hear the speaker - then you just have to figure out the wiring mess. (J18 is a good start)
Locate J10 and J26 - these sometimes get swapped - one goes to the Mic Board and handles the TX/RX switching (J26) while J10 is the Roger Beep - goes to the CB/PA/RB switch.
So, if you get TX audio - does Beep work?
Why?
Do you hear a thunk from the speaker when you power up? If so -Then a brand-new Audio Chip isn't the first thing on your list - but if you don't hear ANYTHING - then suspect speaker wiring more than the Audio Chip - push the chip down a few steps in your "gotta' do-this list"
If you hear a Thunk - check Squelch - see if that pot is dirty or can even set background hiss - pop noise from the open and closing of Squelch when you operate the control.
Ok, still no?
Then check to see if the EXT SP jacks switch contacts are "stuck" open - making no contact - it's the first thing the Audio Amp routes to past the CB/PA switch. This test is only for EXT Speaker - there is a common at the CB/PA/RB for the Speaker - which is also for PA - those route thru J18 from the front panel back to the main board - where it's common ground.
So, another test would be to simply jumper the "black wire" from the Speaker (-) terminal back to any foil ground and see if you hear the speaker - then you just have to figure out the wiring mess. (J18 is a good start)
Locate J10 and J26 - these sometimes get swapped - one goes to the Mic Board and handles the TX/RX switching (J26) while J10 is the Roger Beep - goes to the CB/PA/RB switch.
So, if you get TX audio - does Beep work?
Andy, thank you for the reply.
No sound at all on neither cb or pa, no internal or external, no thunk whatsoever.
Yes, the Roger Beep works on the receiving radio as well.
It receives according what the meter on the radio says, and it transmits too.
Worked and cleaned both jacks, even swapped the i.c.with a brand new identical one and made no difference as voltages were the same as before. Removed bezel, Chased wires to the pa/cb switch looking for suspect connections or pinched wire, chased the tone control switch as well and found nothing. Volume control feels ok and all plugs are tight as they should be.
I get no voltage at the speaker or p.a. solder pads in either mode.
I ran out of time and juice tonight. Tomorrow afternoon I'll try grounding the - speaker terminal and check the j18 as you mention.
I appreciate your help and will report back tomorrow.
No thunk? And replaced IC?
But USE J4 (ODD COLOR/White Plug) on the main Volume/SQ/RF Gain
(From a 939 - -30Z board)
This may be more of a routing wire problem
But USE J4 (ODD COLOR/White Plug) on the main Volume/SQ/RF Gain
(From a 939 - -30Z board)
- the speaker is not getting hooked up
- This means the CB/PA/RB switch at the front panel might be goofy - locate J4 / J9 (odd colored plugs/jacks) these are part of that mess - just examine them - make sure they aren't broken or otherwise oddly assembled - or don't look like the others - these route Audio and MIC functions to and from this board.
- RB GROUNDs to enable it (That is Roger Beep function)
- J14 on main PCB also utilizes that CB/PA/RB switch - it turns on or off the various Audio / Volume or PA Amp - but also turns on or off the RX to be "AGC'd" and Detected - so look for 8V on AM at J14 when in CB Mode, but OFF in PA - can be set to ON (but SHOULD BE OFF) in RB (RB works thru the other POLE of this switch) if it's stock - so if someone worked in this area - that effort shows up here...(what I mean by this phrase is that the RB function is possible - but to set it up requires you -the tech- to do this)
- What I've seen done - was done in error - the RB function if it's GROUNDED will kill a lot a traces from the Dead short it causes on the 8V line in one pole. This takes out several diodes (or can) because of the power push - but if it opened up the switch - you don't hear any audio because the switch may have opened up.
- So, look for this...
- - the EXT SP and PA jacks pin labeled DG s/b CG
- - those are the first things the Audio Amp ties into but it has to find GROUND to return thru - so, that is at the front panel switch.
- - you can always work a speaker into the output of the Audio Amp - thru C177 - that big output coupling cap
- you should be able to take a simple speaker and hear audio right at that caps output
- - if you don't hear noise or hiss - locate the CB PA connection to its front panel switch (J18)
- - This is so you can install a simple speaker to check and if you DO hear speaker - it means Audio's fine, you just have to locate the issue in the slide switch to Knob assembly
- - Just Keep Audio disconnected at J18 you can pull it off the main board and prevent a further problem of potentially blowing the Audio amp from a no-load or shorted condition you aren't able to find yet.
- I'd start looking to see if you can find speaker output by tracing and continuity checking that C177 to the EXP SP jack - make sure you see a short - if you don't then the foil opened up or the CB/PA/RB switch board is causing this - as it may not be bad, just needs reflowed solder to finish up the connections and or remove potential shorts..
Last edited:
OK Andy,
Got to spend just a little time on it this evening and this is what was doable with time.
This mosfet board with the tda2003 has a slightly different layout so there are a few differences.
You mentioned continuity check from c177 to speaker jack at j18 but in this case I believe it would be c184 to j18 and I verified continuity from c184 to j18 on the solder side.
J18 on the front panel pcb has nothing at all on any of the modes (cb/pa).
I sprayed out the cb/pa/rb switch with cleaner and air and changed nothing. Removed the front panel pcb that has control knobs and wire jacks to inspect solder traces, plugs etc. All look fine and reflowed suspect joints.
Reflowed joints around j4 and found a spot on the main pcb that doesn't look right.
That's about all I had time to do so tomorrow will take another jab at it. I've added a few pictures below just for reference.
Got to spend just a little time on it this evening and this is what was doable with time.
This mosfet board with the tda2003 has a slightly different layout so there are a few differences.
You mentioned continuity check from c177 to speaker jack at j18 but in this case I believe it would be c184 to j18 and I verified continuity from c184 to j18 on the solder side.
J18 on the front panel pcb has nothing at all on any of the modes (cb/pa).
I sprayed out the cb/pa/rb switch with cleaner and air and changed nothing. Removed the front panel pcb that has control knobs and wire jacks to inspect solder traces, plugs etc. All look fine and reflowed suspect joints.
Reflowed joints around j4 and found a spot on the main pcb that doesn't look right.
That's about all I had time to do so tomorrow will take another jab at it. I've added a few pictures below just for reference.
Attachments
Adding to this, here is the suspect trace I found while reflowing j4.
There is a separation as pointed by the arrow (excuse my photo editing) that doesn't look like it's supposed to be. Is that a defective trace or is it supposed to be? I can't find a foil side picture to compare with. Looks like it should be a solid trace but that's only an assumption.
There is a separation as pointed by the arrow (excuse my photo editing) that doesn't look like it's supposed to be. Is that a defective trace or is it supposed to be? I can't find a foil side picture to compare with. Looks like it should be a solid trace but that's only an assumption.
Taking another stab at it this evening to see where it goes. Will be printing the schematic to see where the map leads.
Any takers on that suspect trace pictured above??
Any takers on that suspect trace pictured above??