Galaxy DX 2547 Died

[Recon]

Four-month old DX 2547. I was monitoring channel 19 and all of a sudden, Bam! no power / no lights, just click, click, click, etc.
The radio is connected to a Astron VS-70M Power Supply with 13.7 volts going to the radio. I switched the selector on the back of the radio to the AC position and connected the 110 AC power cord and same issue. The only modification is that the extra channels have been added. Is this a simple fix or a candidate for the garbage?

 

[Robb]

Hard to say.
Blew the voltage regulator?

 

[Recon]

I have no idea what it is. When I push-in the On/Off button, the radio just continues to click on and off at one-second intervals but it does not turn on. Sort of a nice radio but the blacked-out control knobs can be a PITA without having a lamp or overhead light on.
Tomorrow my new President McKinley will arrive and I'll give it a try as my base radio.

 

[loosecannon]

a complete failure is much preferred to a "weak receive" or "ssb power is low but AM is fine".

there is a part in your radio, maybe more than one that has stopped doing its job.

you just have to find it.

the good news here is that the whole radio is dead, so you are dealing with devices that supply power to the whole radio, which narrows the search significantly.

the other good news is that you should be able to troubleshoot this with a digital multimeter.
as long as it reads DC volts that could work, but it would be preferable if it had the diode test function too.

My answer is fix it!

let's start with the schematic found here:
http://www.cbtricks.com/radios/galaxy/dx2547_mosfet/graphics/galaxy_dx2547_main_tda2003v.pdf


you can see that the positive lead from the power supply is the one being switched in and out of line when you switch the AC/DC switch on the back of the radio.

the negative line is still connected to the power supply and the radio in both positions, so the first step is to disconnect the negative line from the switching power supply in the radio. i believe its just a screw terminal.

remove that wire, and tape up the end so it doesn't short to anything, and try connecting the radio to DC power again.
does it work now?

if so, then your switching power supply is bad and needs to be replaced.
you can find megwatt power supplies in the right size and amp rating here on the forum, and elsewhere.

if it still doesn't work, at least we've eliminated it from our testing.

now we will move on to the first active device (transistor or integrated circuit) on the main 13.8 voltage line. (we always suspect active devices first, and then passives like resistors and caps, because active devices are more prone to failure by nature)

the next things we see in line with the main VCC line are Q54 which is your AM regulator and will be the large transistor mounted to the chassis wall near the rear right corner of the board.

unsolder the three legs of this transistor from the board and pull them loose so they are not touching the board.
now check out this page which will tell you how to test the transistor:
https://vetco.net/blog/test-a-transistor-with-a-multimeter/2017-05-04-12-25-37-07

this transistor is a B C E when looking at the front of the transistor with the legs pointing down.

let us know what the results of this test are.

leave the legs of Q54 unsoldered for now, and move on to the next test below.

the other thing that is in line with your VCC line that might cause this is your audio chip, which is IC8 a TDA2003.
it looks like a final transistor but with 5 legs.

unsolder pin 5 of this IC and lift it away from the board. pin 5 is the far right pin when looking at the front of the transistor with the legs facing down.

now try to turn the radio on with pin 5 disconnected.

you won't get any audio, but the lights should at least come on and the radio should not click off.


yes, i kind of have you testing two things at once, but it should still lead you in the right direction.

post back with the results of your tests.
LC

 

[Recon]

a complete failure is much preferred to a "weak receive" or "ssb power is low but AM is fine".

there is a part in your radio, maybe more than one that has stopped doing its job.

you just have to find it.

the good news here is that the whole radio is dead, so you are dealing with devices that supply power to the whole radio, which narrows the search significantly.

the other good news is that you should be able to troubleshoot this with a digital multimeter.
as long as it reads DC volts that could work, but it would be preferable if it had the diode test function too.

My answer is fix it!

let's start with the schematic found here:
http://www.cbtricks.com/radios/galaxy/dx2547_mosfet/graphics/galaxy_dx2547_main_tda2003v.pdf


you can see that the positive lead from the power supply is the one being switched in and out of line when you switch the AC/DC switch on the back of the radio.

the negative line is still connected to the power supply and the radio in both positions, so the first step is to disconnect the negative line from the switching power supply in the radio. i believe its just a screw terminal.

remove that wire, and tape up the end so it doesn't short to anything, and try connecting the radio to DC power again.
does it work now?

if so, then your switching power supply is bad and needs to be replaced.
you can find megwatt power supplies in the right size and amp rating here on the forum, and elsewhere.

if it still doesn't work, at least we've eliminated it from our testing.

now we will move on to the first active device (transistor or integrated circuit) on the main 13.8 voltage line. (we always suspect active devices first, and then passives like resistors and caps, because active devices are more prone to failure by nature)

the next things we see in line with the main VCC line are Q54 which is your AM regulator and will be the large transistor mounted to the chassis wall near the rear right corner of the board.

unsolder the three legs of this transistor from the board and pull them loose so they are not touching the board.
now check out this page which will tell you how to test the transistor:
https://vetco.net/blog/test-a-transistor-with-a-multimeter/2017-05-04-12-25-37-07

this transistor is a B C E when looking at the front of the transistor with the legs pointing down.

let us know what the results of this test are.

leave the legs of Q54 unsoldered for now, and move on to the next test below.

the other thing that is in line with your VCC line that might cause this is your audio chip, which is IC8 a TDA2003.
it looks like a final transistor but with 5 legs.

unsolder pin 5 of this IC and lift it away from the board. pin 5 is the far right pin when looking at the front of the transistor with the legs facing down.

now try to turn the radio on with pin 5 disconnected.

you won't get any audio, but the lights should at least come on and the radio should not click off.


yes, i kind of have you testing two things at once, but it should still lead you in the right direction.

post back with the results of your tests.
LC

Thank you for the troubleshooting guide, but I am not a radio "guru" and I've lost interest in continuing on to get this radio repaired. If the radio could not last four months with approximately only fifteen days of operation, I may take it to the rifle range and destroy it and accept my loss.

 

[OldTech03]

So send it to me I will pay the shipping and a little extra? What about that idea?

 

[w9cll]

Thank you for the troubleshooting guide, but I am not a radio "guru" and I've lost interest in continuing on to get this radio repaired. If the radio could not last four months with approximately only fifteen days of operation, I may take it to the rifle range and destroy it and accept my loss.

You say you are old school CB so what you want is the way radios "used" to work. Those days are long gone, quality manufacturers have abandon the bussiness and all that is left are the low cost alternatives. If you are a sideband user thet get a ham rig and have it modded for 11 meters, if you a AM guy well then good luck in your search.

 

[Tallman]

Thank you for the troubleshooting guide, but I am not a radio "guru" and I've lost interest in continuing on to get this radio repaired. If the radio could not last four months with approximately only fifteen days of operation, I may take it to the rifle range and destroy it and accept my loss.

Pack a couple of pounds of "Tannerite" around it let the parts fly!

 

[Knoxduder]

a complete failure is much preferred to a "weak receive" or "ssb power is low but AM is fine".

there is a part in your radio, maybe more than one that has stopped doing its job.

you just have to find it.

the good news here is that the whole radio is dead, so you are dealing with devices that supply power to the whole radio, which narrows the search significantly.

the other good news is that you should be able to troubleshoot this with a digital multimeter.
as long as it reads DC volts that could work, but it would be preferable if it had the diode test function too.

My answer is fix it!

let's start with the schematic found here:
http://www.cbtricks.com/radios/galaxy/dx2547_mosfet/graphics/galaxy_dx2547_main_tda2003v.pdf


you can see that the positive lead from the power supply is the one being switched in and out of line when you switch the AC/DC switch on the back of the radio.

the negative line is still connected to the power supply and the radio in both positions, so the first step is to disconnect the negative line from the switching power supply in the radio. i believe its just a screw terminal.

remove that wire, and tape up the end so it doesn't short to anything, and try connecting the radio to DC power again.
does it work now?

if so, then your switching power supply is bad and needs to be replaced.
you can find megwatt power supplies in the right size and amp rating here on the forum, and elsewhere.

if it still doesn't work, at least we've eliminated it from our testing.

now we will move on to the first active device (transistor or integrated circuit) on the main 13.8 voltage line. (we always suspect active devices first, and then passives like resistors and caps, because active devices are more prone to failure by nature)

the next things we see in line with the main VCC line are Q54 which is your AM regulator and will be the large transistor mounted to the chassis wall near the rear right corner of the board.

unsolder the three legs of this transistor from the board and pull them loose so they are not touching the board.
now check out this page which will tell you how to test the transistor:
https://vetco.net/blog/test-a-transistor-with-a-multimeter/2017-05-04-12-25-37-07

this transistor is a B C E when looking at the front of the transistor with the legs pointing down.

let us know what the results of this test are.

leave the legs of Q54 unsoldered for now, and move on to the next test below.

the other thing that is in line with your VCC line that might cause this is your audio chip, which is IC8 a TDA2003.
it looks like a final transistor but with 5 legs.

unsolder pin 5 of this IC and lift it away from the board. pin 5 is the far right pin when looking at the front of the transistor with the legs facing down.

now try to turn the radio on with pin 5 disconnected.

you won't get any audio, but the lights should at least come on and the radio should not click off.


yes, i kind of have you testing two things at once, but it should still lead you in the right direction.

post back with the results of your tests.
LC

Thank you for this,
I have one I recently picked up, and while I was monitoring 19 one night, the sound stopped. I thought it was the squelch, but nope. Then when I keyed it started rapidly clicking. I recycled the power, and the lights barely flickered to on

This is my first radio after being out and away for 25 years, and I no longer have a soldering iron or clamp. I will try it on a battery, but the timing as horrible as the only shop around, he isn’t coming to work.

I hope everyone is safe and well with whAts going on on.

 

[Big Kahuna]

You're going to shoot a $300 radio? Hopefully you're joking and are just going to return it. Or call Galaxy, it's still under warranty. 2 years for galaxy radios.

 

[Handy Andy]

You may have just touched on something that not many have realized and it's why I get pissed when someone doesn't always believe what I say...It's not you, there is a past behind this radio...I got flamed before in trying to help...but here goes...

You may have a two-fold problem.

If you don't know what I'm talking about, well I'll put it this way, it's like using the parts from a Model - A to fix a Lamborghini - they don't fit well and are not compatible...

One - the mains?

The Finals - if that has the MOSFET ones, like the IRF520 - then the Power supply got taxed and is heading to quit - pretty much presume it's (Mains power supply) a gonner and You'll need another...



But, there is hope, you can use 10Amp Power supply to power the Radio using the optional power jack on the Rear panel - set the Switch to DC and use the "uniden style" connector to run it...

​

But, before you do that, go in the radio itself and Pull TP-7, TP8, TP9 jumper (Mirror board) - the one over by the Finals...

​

Because....

The MOSFET trimmers used in the radio are based upon an older Bi-polar design.



If the original was taxed, you don't want the Finals to pop from regulation issues - or worse, these may need to be "checked and re-trimmed" to proper Bias levels - for age can make the Pots drift HIGHER in values - which RAISES the Bias voltage - Which FORCES the IRF-520's to turn on - even when there is no TX power directly to them - they can do this from the poor regulation clamping done back at the boards regulator itself.

The RX TX switch is not foolproof and will "spike" the TX line...rapid on/off conditions do this...

This design is an ANALOG type​

Once the radio is switched over, now you have time to figure out how to fix the on-board 110V power supply or just replace with a switching type...your local CB Shop guy may know some tricks...

 

[Big Kahuna]

I didn't mention the obvious but did you check the fuse holder in the back of the radio. May have just blown the main power fuse.

 

[Knoxduder]

I’m glad I found this. My 2547 died too. At first the speaker went out, no audio.. Then when I keyed up it clicked a lot. Recycled power , no joy. Went from AC to DC, no joy.
I hear it’s mostly the power supply, and they are known to have these issues.
I heard they over heard as well: