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Galaxy DX 959-300, project possible?

Hawkeye351

Well-Known Member
Jun 27, 2021
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Got my hands on a Connex 4300-300 that has a cracked main board, but amp section is fine.

Was thinking of removing the amp and installing in my personal 959. I know how to trace down the wiring from one to the other, but unsure if this is even possible.

Is there any chance this could work?
Any parts that would need to be removed, swapped?
What issues may I encounter in the swap of the amp from the connex over to the 959?

I have the complete connex, covers and all, even the large power input jack and cord. So the swap should be easy, but may need some assistance from the pros on here.

This is just a project of mine for my personal radio.

I already have the baddest Galaxy DX 949 around, which I call my "Stryker Killer", but would like to make another Stryker Killer using the connex 4300-300 amp installed on my Galaxy DX 959.

It'll be a one of a kind 959, which will be renamed to Galaxy DX 959-300.

Yes, I love this hobby...
 

I got a galaxy dx959 with a rci2970 bottom on it worked out pretty good. Only problem I am having now with it is I think the relay on the board starting to go bad. It will give me something else to work on. When you get done can you take a picture of it and post it.
 
Still in the works, just having to work on it here and there in between others radios.

According to the schematic comparisons between the 2 different radios, it is possible and shouldn't be too hard.
 
It should work. Just try not to smoke the 1446 finals in the amp section, that would be about a 200 dollar repair. Also since this came from an AM/FM only radio there will be some additional adjustments since the 959 is a SSB radio. It won't just be plug and play.
 
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It should work. Just try not to smoke the 1446 finals in the amp section, that would be about a 200 dollar repair. Also since this came from an AM/FM only radio there will be some additional adjustments since the 959 is a SSB radio. It won't just be plug and play.
what i would do is instead of rf sensing, i'd wire the relay trigger right to a point in the radio connected to the ptt or something so there would be no delay needed
 
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I rigged up a PNP switching transistor on the solder side of my 1st Gen 2970, I think I used the R.Beep logic from the CPU up front, rerouting the signal to this PNP transistor. The Emitter leg goes to the +8v TX line on the board, where the Brown and Black wires go to that key the amp. The Collector (center leg) goes to the Brown wire pin on the board, and a resistor goes to the repurposed R.Beep pin in the front where the CPU board connects to the main board. I need to pull it out of storage and take photos. I did this on another 2970 a few (over 25?) years ago when I had another 1st Gen in the before time.
R.Beep on in the LCD screen, = Amp on. Off = barefoot (single final).
 
I built a cheapo MOSFET amp over a decade ago to experiment with on a 959. Haven’t used it in years and it got kinda rusty laying around. It was AB biased, small board in front of the input transformer, and a small keying board by the relay, tried to keep it compact. No photos of it on the radio as the radio is in pieces in the basement somewhere, was not my main radio and was just used for experimentation. This was all just for fun playing around so don't be too critical, it was meant to do about 100w peak or so. It worked okay. I don't think I had any ferrite / choke to do the power lead at the time, but again, was just something to play around with.

But yeah, can certainly add the cover style amp to a 959.

Just browsing the forum and this thread made me think of this thing. :ROFLMAO:


IMG-0982.jpg


IMG-0988.jpg


Just found this pic when I was working on it, a little less rust. Use a variable bias to dial it in, then set it fixed if I recall.
thumbnail-DSCN9223.jpg
 
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I dig that. i remember that 6 fet schematic floating around cb tricks forum years back. never made a move on that one
Yeah I tinkered with a lot of these back then in junk old amp heatsinks, biggest I did like this was 8 520's, 4 parallel per side, I have a photo of it somewhere. I liked the 4x520 amps for low power / reliability and used one for years.
 
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Well, I did not get to do the 959-300 I wanted to do. But a local that does a little tinkering with electronics wanted to try putting it on a Galaxy 55v.

I helped him out here and there on the schematics cross references, since they're both different boards. Everything went great, no hiccups whatsoever.

The end result:

Galaxy DX 55V-300.
Deadkey varies from 3w up to 75w.
Swings 400w to 425w PEP.
Runs very cool and sounds amazing.
It's his daily talker now, lol.

Moral of the story,
You can accomplish anything if you put your mind to it and don't give up.
 

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