converting new dx959 from mosfet to transistor

[9C1Driver]

I would leave the mosfet final as it is and have a proper tune and alignment done. It really does not matter if it does 20,25,or 30 watts. Since you must DOUBLE your power to make a difference your better off getting a small 200-300 watt amplifier.

 

[Staybolt]

Why do so many on here try to discourage others from wanting to mod their radios? I thought that was what this forum was about, helping others NOT criticising them.

 

[sonoma]

Why do so many on here try to discourage others from wanting to mod their radios? I thought that was what this forum was about, helping others NOT criticising them.

they are just saying you are farther ahead leaving the radio with the mosfets.liked I told him in a earlier post look at the install sheets to try and look at what you have to reverse the mosfets to bipolar tranns.
I mentioned Defpoms sight. here is a link to cbtricks you can look at and see what you have to put back and change it to bipolars.for the effort involved you are better off with the mosfets. if the radio is tuned properly it should put out more with mosfets. this link even shows how to install the 2nd final instead of just the one that comes factory

http://www.cbtricks.com/miscellaneo.../galaxy_dx949_959_2547_erf2030_mod_rev1-2.pdf

 

[MudDuck442]

I agree with 9C1 all the way. All that work for something trivial at best..and you said the reason why is because you are more familiar with modding the bipolar chassis. What do you mean by mod? If it is typical "internet mods" which seems to be the way this is going due to the fact that you are asking how to change them to bjt transisors... well my guess is that you would end up with a bipolar transistor output section capable of high IMD and other possible spurs detected by a wattmeter as a few more watts out output power..which is once again.......trivial at best. Sorry..but being honest here.

Second..if you operate SSB please don't replace the stock varactor or add a choke in series. It will make it a real pain to tune SSB. If the wind blows the wrong way and it moves a millimeter you'll move a lot in frequency. It will be way too touchy. If you operate AM and you goal is go to in "bwtween" channels then I could see it being worthwhile..maybe.

 

[MudDuck442]

Staybolt.. just saw your post... yes part of it is encouraging people..the other part is to separate the BS from the typical "cb" tech nonsense that floats around. In a way it's helping out you fellow radio operator / tinkerer.. if they still want to do it against all advice..hey have fun...but you have a responsibility to at least try to point them in the right direction. If we all had the go with the flow mentallity of hey man.. go ahead and try this mod..try that mod..knowing it is not correct or good practice we are doing NOTHING for the radio community except promoting more CB myths like "18 feet of coax" "more swing in the thing" "swrs plural incorrect use) has got to be low to get out) "you're hitting me 9 pounds instead of s units" teaching people that it takes 4 times the amount of power to go up one S unit which is correct. The list goes on and on. This is technical in nature. The rules of electronics don't have emotion nor do they try to encourage or discourage. If someone wants to do it themselves and learn...that is GREAT! (And encouraged) BUT if someone is going to mod their radio not knowing what they are doing but only because "so and so said it was good" then they need to think before putting it on the air or risk messing up their stuff. We could say "hey it's their money and business what they do"...true..but at the same time this is a public forum and they asked.

 

[Lil'Yeshua]

If you like to experiment then go ahead and please post your results. Personally,if I wanted to increase my power output then I would at least put a KL-203P inline but a 250 or a 500 watter would get me descent results. But seriously,these guys are trying to save you a lot of grief but if you like to experiment,...

 

[Brake Weight]

I worked with a Serbian mechanic once. He has a Honda Del Sol that he made into a convertible and installed a bored out blueprinted SC Alpha Romero inline 6.

'Why?' I asked.

'Why not?' Was my reply.

 

[jef]

Okay i'll leave the mosfets.Doing my full alignment as i did on the old transistor dx959 pulled jumper board checked ma between tp7 and tp9 and got 3.5 for transistors this was set at 50ma and between tp7 and 8 i get 1.8ma on the old radio i set it at 100ma.Should i just set the gate voltage to 3.5 and forget about what the ma reads on tp7 8 9 because they arent jiving and yes it is in ma setting when checking them.Also sorry to offend anyone with these stupid questions.Did a full alignment on my orignal dx959 and it needed it as i am sure this does too.I was very familiar and succesful with the transistor version of this board,but with the mosfets it is throwing me a curve on the bias alignment.Got the slide i needed by changing c130 from 20pf to 4pf and r153 from 12k to 10k.5kc up 6 kc down little touchy though but i use it as a base with a ext freq counter so it doesnt bother me.

 

[n0zna]

the 477 i did to alot of radios when i ran 11 mtrs only...i made a board like a stinger board.Had a old grant,and also did a friends rad shack knock off of a pc122,it had the 2824 pll and chaged it to something...dont rember what,was in 1982...73 de JW

 

[Staybolt]

"except promoting more CB myths like "18 feet of coax" "more swing in the thing" "swrs plural incorrect use) has got to be low to get out) "you're hitting me 9 pounds instead of s units"

You forgot "your coax length matters!" and "Your clarifier has to be open so the other ops don't bitch about you being off freq!" LOL

 

[MudDuck442]

I certainly could have written a novel on it but figured I would save the people reading the thread agony and instead find a way to market a 2sc2999 as the best upgrade for a cb receiver with already too much gain in the front end.

 

[jef]

For everyone the Galaxy tech said dont worry about the ma readings on the bias on tp7,8,9 just set vr 12 so l37 has 4 volts and set vr10 so l33 has 4 volts channel 1 usb tx on the mosfet only chassis.Thought id post this it may help someone trying to get this set.

 

[Robb]

For everyone the Galaxy tech said dont worry about the ma readings on the bias on tp7,8,9 just set vr 12 so l37 has 4 volts and set vr10 so l33 has 4 volts channel 1 usb tx on the mosfet only chassis.Thought id post this it may help someone trying to get this set.

What Galaxy sent me:


Robert,


The Gate voltages are set in SSB TX mode with the Mic gain at Min.

Driver 3.6 VDC +/-.1VDC

Final 3.4 VDC +/-.1VDC

All other alignment adjustment in the service manual is correct for use on the newer model radio.


Regards,
Jon

Do these voltages make a difference?
Yes; they are sensitive to too much voltage over the long run.
Just a FYI . . .

 

[MudDuck442]

Hey Jon..good info. I could see someone either trying to adjust (read: misadjust) it on AM or SSB with the mic up picking up noise in the background.

 

[jef]

So whats right on the bias what the tech on the phone at galaxy tech said or the tech that emailed different readings,Mudduck do you know the answer or how bout you Robb.You guys seem very educated on these.Mine is working great on 4 volts but i have a problem with two different techs giving different numbers.I know the biasing will effect your signal on a spec analyzer and i want a clean signal. With my bias at 4 volts my ma readings at tp7,8,9 are very close now to 50 and 100 .They are 48 and 100 I am pretty sure my ma reading will be considerbly lower if i drop down to 3.4 and 3.6 but i have read to not allow gate voltage to exceed 3.75 volts,If that is true then my Galaxy tech told me to and it put the ma right on the test pins.Let me know the proper setting and if the achieving the proper ma's on the pins is more important than possibly exceeding the volts.