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Galaxy dx 77 hml questions

Ok so would the irf 520s do any better ?

Also heres what I know about the radio .
Supposedly its an original dx 77 hml that was single final converted to double finals.
It has the 2 mosfets in it. And the tech now said he thinks he remembers seeing board cancer?? Don't know bout that one unless he means corrosion
 
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Cmessina said:
Ok so would the irf 520s do any better ?

Also heres what I know about the radio .
Supposedly its an original dx 77 hml that was single final converted to double finals.
It has the 2 mosfets in it. And the tech now said he thinks he remembers seeing board cancer?? Don't know bout that one unless he means corrosion
Click to expand...
No; they are the same thing.
One rule about radio BTW; don't try to ring every last watt out of it. It will create a radio that has too much distortion - regardless if it 'sounds good' to some local goober who doesn't know any better. Second, pushing a mosfet final radio (like yours) will end in blowing them up just for few lousy watts. Keep them cool by not pushing them too hard with too much modulation.

No; all of the DX series came with bipolar (non-mosfet) finals, and the 77, 88, & 99 were all dual final radios.

Board corrosion happens when an electrolytic cap leaks out and destroys traces on the bottom of the board. Might be from another cause, like getting it wet (from a flood) and not drying and cleaning it off - for example.
 
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Nope; it came from the factory with two 2sc2312 final transistors. Just looked at the schematic for it. They all have a heat sink on the back. That is not a license to push the radio too hard, since the mosfets will STILL fry. Don't believe so? Go ahead and find out for yourself.
 
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Nope that's why I'm here you guys know more than I do. I'm just talking so I can learn more.
Also the Board cancer as he called it was a black and green spot on the board.
And final comment/question is I have a cousin whom can build almost anything electronic he said if the board does have a bad spot he can cut and build a new one if he can find all the components.
Would it be worth it to let him do so?
 
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Fiberglass is the material that is used for radio boards. Unless it was burned, then only the traces have corroded. So what most techs will do is use jumper wires. Which is a proper fix if they cannot re-connect any of the traces with solder joints. If a board has been burned; then they will use an epoxy patch. Trying to put a new board in place with be fraught with disaster, toil, and time. See if he can fix it. If not; then get a fully populated replacement board from eBay or RF Parts - if they still have them
 
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Thanks for the info and advise. My goal is to keep the radio in good working condition as long as possible.
 
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Like i said dont run it full throttle back off a bit n let it work for you.it will serve you well if not pushed hard and use a good antenna with low swr.4 watts will reach far on a great proper set antenna.50 watts wont reach far on an improper antenna
 
Wilson t2000 set to 1 swr on ch 40 and just barely above 1 on ch 1.

Radio is set to high and mix gain is halfway
 
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Several observations.

1) The Galaxy 77 was a dual final radio with either 1969 or 2312 finals and a heat sink. These are NOT mosfets. It was an honest 25-35 watt radio, maybe 40 with a decent correct tune-up.

2) Yours has had some major work done if it runs 2030 mosfets . This is why it does 45-55 watts now.

3) Get yourself a decent little external watt meter so you will know what it's doing. So far you have stated this shop told you 55,50,45, and 40 watts. Many cb shops have loose watt meters to make their customers happy.

4) Set your mic gain at 2/3 to 3/4 and enjoy the radio. It is doing all it can so don't dick around with it anymore. From here on out you will have to double your power or NO ONE will even notice.
 
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9C1Driver said:
Several observations.

1) The Galaxy 77 was a dual final radio with either 1969 or 2312 finals and a heat sink. These are NOT mosfets. It was an honest 25-35 watt radio, maybe 40 with a decent correct tune-up.

2) Yours has had some major work done if it runs 2030 mosfets . This is why it does 45-55 watts now.

3) Get yourself a decent little external watt meter so you will know what it's doing. So far you have stated this shop told you 55,50,45, and 40 watts. Many cb shops have loose watt meters to make their customers happy.

4) Set your mic gain at 2/3 to 3/4 and enjoy the radio. It is doing all it can so don't dick around with it anymore. From here on out you will have to double your power or NO ONE will even notice.
Click to expand...

Always have used an external watt meter. Currently using an astatic pdc1 and with the roger beep the best I've seen it swing is about 35.
The tech did tell me via a phone call that he never lets a radio leave his shop wide open. Stated that he wants happy customers with radios that last
 
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the "board cancer" is corrosion setting in to the copper traces. you can sand it away and hope that it hasn't gotten too deep, then re-coat the board with PC board sealant.

It is not worth it for your relative to try to make a new PC board for it. it would be easier to just buy another one.

if your radio swings to 50 watts from all deadkey settings, then it has had a modulation mod done to it. that does not necessarily mean that the limiter has been clipped, and my guess is that he did an NPC mod to it. if he did it with a scope, then it can work well, but most that do that mod do not use a scope and just set things for maximum.

this is probably the reason why people close by say you are distorting. just turn the mic gain down a bit when talking to people close by.

not sure why he set your deadkey so low, unless he thought you were going to be running an amp with it.

your deadkey settings should be something like, 1 watt on low, 3 watts on medium, and 6 watts on high. don't go over 6 watts on high.

you can adjust these yourself using the info on CBtricks if you like.

take a look in the radio near the finals. see those copper colored spring looking things?
are any of them spread apart or otherwise messed with?

if so, and your tech did it, go slap him. if they already were spread and he didn't fix them, ask him why.

if they are not, then that is great! don't ever mess with them.

the tendency is to want to mod things like this to the hilt, but everyone here is going to rightfully advise you against that.

remember, to increase your signal in someone else's receiver by 1 S unit, you need to quadruple your power. that is true no matter how many watts you start with.
putting out 4 watts, hitting someone with an S5? want to get to S6 on their meter?
it will take 16 watts. starting with 400? you will need to up it to 1600 watts.

with this knowledge, you can easily see why messing around in your radio trying to get an extra 10 watts is futile.

If the radio works, use it and enjoy it.
It is almost 30 years old and at some point the electrolytic capacitors inside will start to dry out and cause weird problems with it.

when that starts happening, it's up to you whether you want to have it fixed, replace them yourself, or just buy another radio. it happens to all electronics eventually.
LC
 
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loosecannon said:
the "board cancer" is corrosion setting in to the copper traces. you can sand it away and hope that it hasn't gotten too deep, then re-coat the board with PC board sealant.

It is not worth it for your relative to try to make a new PC board for it. it would be easier to just buy another one.

if your radio swings to 50 watts from all deadkey settings, then it has had a modulation mod done to it. that does not necessarily mean that the limiter has been clipped, and my guess is that he did an NPC mod to it. if he did it with a scope, then it can work well, but most that do that mod do not use a scope and just set things for maximum.

this is probably the reason why people close by say you are distorting. just turn the mic gain down a bit when talking to people close by.

not sure why he set your deadkey so low, unless he thought you were going to be running an amp with it.

your deadkey settings should be something like, 1 watt on low, 3 watts on medium, and 6 watts on high. don't go over 6 watts on high.

you can adjust these yourself using the info on CBtricks if you like.

take a look in the radio near the finals. see those copper colored spring looking things?
are any of them spread apart or otherwise messed with?

if so, and your tech did it, go slap him. if they already were spread and he didn't fix them, ask him why.

if they are not, then that is great! don't ever mess with them.

the tendency is to want to mod things like this to the hilt, but everyone here is going to rightfully advise you against that.

remember, to increase your signal in someone else's receiver by 1 S unit, you need to quadruple your power. that is true no matter how many watts you start with.
putting out 4 watts, hitting someone with an S5? want to get to S6 on their meter?
it will take 16 watts. starting with 400? you will need to up it to 1600 watts.

with this knowledge, you can easily see why messing around in your radio trying to get an extra 10 watts is futile.

If the radio works, use it and enjoy it.
It is almost 30 years old and at some point the electrolytic capacitors inside will start to dry out and cause weird problems with it.

when that starts happening, it's up to you whether you want to have it fixed, replace them yourself, or just buy another radio. it happens to all electronics eventually.
LC
Click to expand...

I was assuming it is corrosion, thanks for the info on that.
I watched the tech with this radio he didn't use a scope just a Dosy meter. He never touched the spring things. And he said someone had done a dirty modulation mod in it.
It has stamps on the inside covers with a signature for a cb shop on texas that no longer exist. Im assuming they did the mosfet conversion the modulation mod the nitro knobs and the original peak and tune.

This tech said the dead key watts are 1 - low. 1 - medium. 3 - high
I have the radio set to high and mic gain is about 3/4
I'm using an astatic mic on the radio and do plan on keeping it in working order.
I have a back up Cobra 29 ltd classic with a Rainmaker mosfet upgrade and Rainmaker variable dead key modulation kit. My cousin installed both according to the schematics included in the packages.

I did the peak and tune after the mods and the tech said he was very impressed with the radio.

I have no plan on maxing out any of my radios. I followed the peak and tune I found on this site.
I will say I'm here because doing the mods the right way and not splattering the modulation is important to me.
I'm the type of guy that believes if your going to do something learn to do it correctly and dont produce trash.
 
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One more important thing Ive forgotten to mention is this radio isn't a black faced unit its a silver faced model
 
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