Galaxy DX86V mods

[Shadetree Mechanic]

Let us, well, me know if the one you got is defect free, works perfectly.

Initial function check before conversion seemed fine. So after the conversion, I flipped around the dial and it sounds really good on AM, have not checked SSB yet. Then I adjusted the modulation a little with the scope and monitor radio. I ended up a little over 100% and sounds great. I have not checked frequency or tried it on SSB because it was time for supper so I will continue later on. Overall this one looks like a winner.

 

[Eldorado828]

More 86v goodness. Going to unsolder my blob now.

I think there was a movie in the 80's named The Blob! Let us know!!

I got the "side mic" 959 today as well so it's Christmas over here too.

 

[Eldorado828]

 

[groundwire]

Initial function check before conversion seemed fine. So after the conversion, I flipped around the dial and it sounds really good on AM, have not checked SSB yet. Then I adjusted the modulation a little with the scope and monitor radio. I ended up a little over 100% and sounds great. I have not checked frequency or tried it on SSB because it was time for supper so I will continue later on. Overall this one looks like a winner.

Well, i guess im gonna try my luck one more time. I bought two and both were defective. Third times a charm hopefully. Gonna order from cb world as well. They are only 1hr away from me so delivery is like one day.

 

[Shadetree Mechanic]

Clarifier mod in this video. I thought that it was already locked transmit to receive from the factory? I guess not. Now I have to check it on my sdr.

 

[Shadetree Mechanic]

Ok I figured out what the deal is. The fine clarifier is RX only. The coarse clarifier is TX and RX. So my question is, how do you adjust the tx when the rx can be changed on a different knob? On a side note, it does over 40w peak on AM. Only a little over 20w on SSB. This is with an ALC adjustment on SSB, it doesn't make a whole lot of difference in power. The biggest difference is what I hear on my monitor radio.

Another question is this:
Is it worth adjusting the SSB transmit cans? Or should I leave well enough alone. It seems that the SSB power should be close to AM peak?

 

[Eldorado828]

Ok I figured out what the deal is. The fine clarifier is RX only. The coarse clarifier is TX and RX. So my question is, how do you adjust the tx when the rx can be changed on a different knob? On a side note, it does over 40w peak on AM. Only a little over 20w on SSB. This is with an ALC adjustment on SSB, it doesn't make a whole lot of difference in power. The biggest difference is what I hear on my monitor radio.

Another question is this:
Is it worth adjusting the SSB transmit cans? Or should I leave well enough alone. It seems that the SSB power should be close to AM peak?

No real answers to your questions but rather comments instead.

I would have expected what you're stating on the ssb power levels too. I'm getting nearly that with the single final 959 that just delivered. Something doesn't seem right so I'm all ears to hear what rabbit hole you're about to go down.

I once a 99v2 that would do between 35 to 40 ssb so I would think that's to be expected. Unfortunately Looks like you might have to work on it to make it shine.

 

[Handy Andy]

Ok I figured out what the deal is. The fine clarifier is RX only. The coarse clarifier is TX and RX. So my question is, how do you adjust the tx when the rx can be changed on a different knob?

This is a throwback from the older Galaxy import days, the RX and TX source is removed, and both the Fine and Coarse are tied together IN SERIES - Fine feeds into Coarse - so they work as one unit thru the PLL 8V Constant feed line.

In doing the above mod, the drift; because of the physical - composition - the drift becomes too excessive for some.

So to be honest - this was one of many reasons why they switched to single - not multi ganged clarifier types.

On a side note, it does over 40w peak on AM. Only a little over 20w on SSB. This is with an ALC adjustment on SSB, it doesn't make a whole lot of difference in power. The biggest difference is what I hear on my monitor radio.

Another question is this:
Is it worth adjusting the SSB transmit cans? Or should I leave well enough alone. It seems that the SSB power should be close to AM peak?

There's still more work to do inside - dealing with Limiter and AVC.

There are three "controlling" systems that monitor the 4558 output - one is fixed. The other two are ALC, and AMC - both look at outputs from the other stages and act upon the Limiter AT THE SAME time AVC is - so when in AM mode ,you have two working the limiter - in SSB still have two working the limiter...

AVC is this...
Older but still locatable in your Galaxy...

​

CB Tricks had all of this stuff discussed a long time ago...

In some ways, it's how we discovered this circuit.
Because of the issues around it...​

Another view from a Galaxy 44 - AVC same circuit...

​

Have to be careful though - DISABLING AVC will TRASH talkback - it will distort the audio ...

​

So how do you properly "correct" it?

Change R172 to a higher value See R177/R178? Locate C131 - piggyback a 560 ohm resistor across this cap to decrease effect AVC does - too low - it can damage the 4558 as well as talkback - so don't go too far.

Also at R172 you can use a variable, to trim current going into the circuit - then sub a fixed value - you have to monitor your talkback as you do this - too little AVC control you get distorted talkback. Once done you can sub in that fixed value and keep your talkback.

I'll try to dig up the tying of Coarse and Fine together in a later post...

 

[Handy Andy]

​

Break RX side (Remove R113)
Break TX Side (Remove D68)
Combine both...
In series - shown above.
Locate Constant 8V DC To PLL.
Attach unbanded side - this to power rail, add wire on other side to go to hole of R113 that goes to FINE voltage feed.
Other ways and tricks

​

The two are added in series, but RX side cuts off Coarse and Fine - this mod ties Fine and Coarse in Series together all the time.

 

[Handy Andy]

Another question is this:
Is it worth adjusting the SSB transmit cans? Or should I leave well enough alone. It seems that the SSB power should be close to AM peak?

"adjusting ssb cans" are the tuning cans for frequency.

Doing that without first doing the PROPER tuning mod , the R113 one, and using R113 in the mod, then you don't have to tweak the cans to bring you back to center slot.

You're better off looking at what I posted about AVC and Talkback if you need both.

The Reason for the AVC was so the Mic Amp gave same results between the different modes - including FM - which is why that AVC is there - you don't have any detectable mod or PEAK with FM - just carrier - so they limit "strength" using the AVC on the FM side,

 

[Shadetree Mechanic]

"adjusting ssb cans" are the tuning cans for frequency.

Doing that without first doing the PROPER tuning mod , the R113 one, and using R113 in the mod, then you don't have to tweak the cans to bring you back to center slot.

You're better off looking at what I posted about AVC and Talkback if you need both.

The Reason for the AVC was so the Mic Amp gave same results between the different modes - including FM - which is why that AVC is there - you don't have any detectable mod or PEAK with FM - just carrier - so they limit "strength" using the AVC on the FM side,

Thanks for all the information to study! I will definitely look at the AVC mod, but talk back doesn't usually work too good because I like to run a hot mic. I also plan on doing the 10kc and roger beep mods. But the clarifier will probably be first on the list, not being able to know where the transmit actually is drives me nuts. If I am talking where I am listening, then I can compensate for any drift as I warm up by listening. I thought about putting this in my truck, but now I am thinking about keeping this one in the shack and buying another one for the truck.

 

[Handy Andy]

To help keep it simple, and you're more than welcome to try this to test your efforts...

AVC to disconnect it - you remove R172 - or R186 on some boards - see above.

To disconnect the MOD amp - Locate D70, or D63 - again see above - per by board - and remove it. Takes out ALC and AMC.

• - HOWEVER - Envelope Control still exists - so if you want peak swings - Q56 needs to be removed

Out of all the mods to keep in place, Keep the AVC for most people even though AVC is more for FM - it is an overall "fail safe" mode for the Mic amp of the radio - Stock or power.

That's where the R172 / R186 trimmer can help devise a plan for the radio to have the talkback - but also have enough "drive" without destroying anything - you can even keep the Limiter in place for AVC uses the limiter only as a means to keep the Mic amp from overdriving all the modes involved.

You will also find that keeping the Limiter in place will reduce the RF noise pickup in the receive as well.

This seems to the the hardest issue for people to know - they rip out the limiter then complain about noise - Hmmm... wonder why? The Limiter also functions as the MIC line MUTE to help keep noise out of the receiver.

 

[groundwire]

Is there a service manual that can be used for the 86v?
If not which VR is for the amc and alc?

 

[Shadetree Mechanic]

Is there a service manual that can be used for the 86v?
If not which VR is for the amc and alc?

I don't believe there has ever been a service manual in the public domain. I used the 979 information. I just got my second one in Friday. Everything checked out good with it after the conversion. I am going to do the roger beep mod, and then it's going in my truck.

 

[groundwire]

I don't believe there has ever been a service manual in the public domain. I used the 979 information. I just got my second one in Friday. Everything checked out good with it after the conversion. I am going to do the roger beep mod, and then it's going in my truck.

So the 979 has the same adjustment points and alignment procedure as the 86v?