Galaxy DX 979 unlocking clairifier

[whiteastro]

I bought a couple of these radios a couple of years back because I could hook a FC-347 frequency counter to them to monitor for drift. Since I have decided I might try my hand at unlocking the clairifier on one of the radios and it would be a first for me. I found this article from cb radio magazine on you tube and was wondering if anybody ever done it and how was your results ? Also they mention adding a jumper wire but don't say what size wire. The article is below click and tell me what you think.

 

[Shadetree Mechanic]

I do this to all my Galaxy radios, especially if they are in a vehicle. Definitely worth doing if you ever want to be on frequency with your transmit. The resistor, diode, and jumper are fairly straightforward. The tricky part is putting the transmit on the same frequency as the receive when you are done. Most people do a full alignment at this point, but all that is really needed is a little tweaking of the transmit oscillator cans for Am, usb and lsb. This can be done with two other radios and a 1khz tone from a phone app or even a YouTube video.

Here is a link to CB tricks with a nice picture to look at.

Galaxy Radios DX979 Service Manual

 

[whiteastro]

I do this to all my Galaxy radios, especially if they are in a vehicle. Definitely worth doing if you ever want to be on frequency with your transmit. The resistor, diode, and jumper are fairly straightforward. The tricky part is putting the transmit on the same frequency as the receive when you are done. Most people do a full alignment at this point, but all that is really needed is a little tweaking of the transmit oscillator cans for Am, usb and lsb. This can be done with two other radios and a 1khz tone from a phone app or even a YouTube video.

Here is a link to CB tricks with a nice picture to look at.

Galaxy Radios DX979 Service Manual

Hey thanks for the heads up, sounds like it isn't as simple as they said it was so maybe I should take it to a pro because I already have too many irons in the fire. LOL

 

[Shadetree Mechanic]

Hey thanks for the heads up, sounds like it isn't as simple as they said it was so maybe I should take it to a pro because I already have too many irons in the fire. LOL

Well, its quite possible that it is that simple and that I am not doing something right? I would like to hear from others if they have to align the Tx with Rx when done.

 

[whiteastro]

Well, its quite possible that it is that simple and that I am not doing something right? I would like to hear from others if they have to align the Tx with Rx when done.

Well I know in my van with the DX979 if I adjust the clarifier to read 27.3850 on the FC-347 for the receive as soon as I key the mic the last digit changes to 2 or 3 and I know that small amount makes a difference in the receive clarity. So I'm assuming it makes a difference in the transmit also. I have a unused DX 979 in my radio room so I'll open it up and see what the job looks like. I can solder & de-solder but have to see how it is to get the old diode and resistor out after it is de-soldered. My manual-dexterity & patience could be better for fine work. LOL Plus is 20 gauge or smaller good enough to make the jumper wire you have to solder in place?

 

[Shadetree Mechanic]

Well I know in my van with the DX979 if I adjust the clarifier to read 27.3850 on the FC-347 for the receive as soon as I key the mic the last digit changes to 2 or 3 and I know that small amount makes a difference in the receive clarity. So I'm assuming it makes a difference in the transmit also. I have a unused DX 979 in my radio room so I'll open it up and see what the job looks like. I can solder & de-solder but have to see how it is to get the old diode and resistor out after it is de-soldered. My manual-dexterity & patience could be better for fine work. LOL Plus is 20 gauge or smaller good enough to make the jumper wire you have to solder in place?

Twenty guage should work. Whatever size fits in the hole in the circuit board would be ok.

 

[SuperLid]

The change in freq when in TX, is due to voltage instability. If the voltage source changes when in TX, so will the freq.

I have done these mods to Galaxy many times and found that it is confusing, if following internet instructions, although the mods themselves are not difficult to do.

I align injecting a 1KHz tone and zero beat the SSB oscillators. The freq counter will read on freq on AM, .1 KHz high on USB and .1 KHz low on LSB.

There are many ways to align these oscillators without the luxury of precision instruments, such as using WWV/CHU in conjunction with a PC running audio software that can display the sine wave when injecting audio into the sound card of the PC, like digipan or audacity.

I use a communications service monitor, with a high stability oven oscillator as the RF/AF source.

SL

 

[whiteastro]

The change in freq when in TX, is due to voltage instability. If the voltage source changes when in TX, so will the freq.

I have done these mods to Galaxy many times and found that it is confusing, if following internet instructions, although the mods themselves are not difficult to do.

I align injecting a 1KHz tone and zero beat the SSB oscillators. The freq counter will read on freq on AM, .1 KHz high on USB and .1 KHz low on LSB.

There are many ways to align these oscillators without the luxury of precision instruments, such as using WWV/CHU or a PC with audio software that can display the sine wave when injecting audio into the sound card of the PC, like digipan or audacity.

I use a communications service monitor, with a high stability oven oscillator.

SL

My problem is I've had no training in this sort of thing and no friends who have so I don't want to make a piece of $180.00 scrap or a 3.5 hour drive to straighten out the mess I made. Sure wish I would have got into this earlier in life for a retirement project especially with the lack of Techs. around here. Most important thing right now is finish my remodeling projects and sell out and enjoy retirement. ( Travel & DXing along the way to the Fishing Hole ) LOL

 

[SuperLid]

My problem is I've had no training in this sort of thing and no friends who have so I don't want to make a piece of $180.00 scrap or a 3.5 hour drive to straighten out the mess I made. Sure wish I would have got into this earlier in life for a retirement project especially with the lack of Techs. around here. Most important thing right now is finish my remodeling projects and sell out and enjoy retirement. ( Travel & DXing along the way to the Fishing Hole ) LOL

It's not difficult. When you get the radio open, I or others will walk you through it. If you are not expanding the clarifier range, the oscillators will still track RX and TX, but your center slot may have changed and you will need to make note of where it is in respect to the front panel. You might just be able to get away with no adjustments, if you are okay with center slot NOT at 12 O'Clock, but you might be there after the mod if you don't expand the range. Clip one end of D68, R113 and lift away from the board (so you can put back to stock if needed). Install a jumper wire. At the end of the day, TX and RX will track, but you may need to hit the clar control depending on the mode you are using. Or, maybe not.....give it a go!

 

[whiteastro]

Thanks for the input, as long as I can still use my FC- 347 Freq. counter I should be OK. I'll check it out in a couple days but have to get outside and do winter prep work right now. Happy DXing !

 

[whiteastro]

Clip one end of D68, R113 and lift away from the board (so you can put back to stock if needed). Install a jumper wire. At the end of the day, TX and RX will track, but you may need to hit the clar control depending on the mode you are using. Or, maybe not.....give it a go!

Would it work if a man only de-soldered one leg of the resistor and diode and pushed those legs away from the PCB but put the jumper in place ????

 

[SuperLid]

Would it work if a man only de-soldered one leg of the resistor and diode and pushed those legs away from the PCB but put the jumper in place ????

Yes

 

[whiteastro]

Yes

Well that might make reversing the mod easier ( In Theory Anyway ) if need be. But I would have a replacement Resistor & Diode on hand just in case. I usually like to have a backup plan for everything I do. Just In Case. LOL

 

[whiteastro]

Just ordered a solder sucker from Walmart, be here Friday.

 

[SuperLid]

Just ordered a solder sucker from Walmart, be here Friday.

Flow solder on the joint you intend to lift out first. It will make removal easier. Other method, would be heat the joint, lift the lead and then clear the hole with the solder sucker.