galaxy DX959's using MOSFETs from the factory? good or bad?

[loosecannon]

so whats the deal with the 959's using MOSFETs?

as far as i know, they used to use the 1969 final, and it was not recommended to do the ERF2030 MOSFET conversion because of the instability it caused on SSB.

now i find out that the 959's are using the ERF2030 from the factory.
does this mean they figured out a way to make the MOSFET work well on SSB, or is the radio now just a crappy SSB radio from the factory?

any inside info from those "in the know" would be greatly appreciated.
thanks,
loosecannon

 

[preacherman]

Don't know if I'd classify myself as "in the know", but I own one of the new mosfet 959's. They tune up to about 25pep with a simple tune. They modified the circuit...and so the "modules" you used to have to put in with the 2030 final are longer needed. BTW, they use an IRF520 mosfet for the final.

It is just as stable as the old ones on ssb, although the output is not as high as the AM swing would cause one to think. I have my final volted, so am seeing 35pep out of it, but the ssb is about 25...any more would produce audible "ringing".

Hope that helps.
preacherman

 

[loosecannon]

preacherman,
that does help, thank you.

so, SSB is not garbled and you get consistently good audio reports?

im thinking that i will do the dual MOSFET final mod to mine because of the amp i want to use with it.

thanks again,
any other info you think i might want to know about this new 959 chassis; please tell me!
loosecannon

 

[Butcher318]

Won't be long and 1969's will be a thing of the past.

 

[loosecannon]

this is exactly why i am asking this question.

did galaxy just use a MOSFET instead of a 1969? basically doing the cbtricks MOSFET mod to a 1969 equipped DX 959?

or did they make some changes to the circuit, allowing decent performance on SSB?

im getting one anyway, i just hope it works ok.
loosecannon

 

[GRTS]

this is exactly why i am asking this question.

did galaxy just use a MOSFET instead of a 1969? basically doing the cbtricks MOSFET mod to a 1969 equipped DX 959?

or did they make some changes to the circuit, allowing decent performance on SSB?

im getting one anyway, i just hope it works ok.
loosecannon

You can compare the schematics side by side for both.

http://www.cbtricks.com/radios/galaxy/dx959/index.htm

 

[loosecannon]

good point ray.

i just did that, and it seems that some inductors have been changed, and some different cap values, and the switching diodes are now zener diodes? if i have my "symbology" right. LOL
the thing that got me, is that in the MOSFET version, L33 and L37 are marked as resistors on the schem. but they say "L" next to them.
they even have resistance values labeled next to them. L33 is a 1K and L37 is a 10K.
not sure what this means.

so it is more than just doing a MOSFET mod to a bipolar 959. OK.

ray, while i have your ear; are there any upgrades to the current board that you recommend?
i know it will void my warranty, but i will already be doing the 2SB817 and NTE153 upgrades, as well as trying the 2SC2999 mod to see if it agrees with this chassis.
so, my warranty will be shot within a short time of my receipt of the radio anyway.LOL
i WILL be making sure that the radio works properly for a while before i attempt any mods to it.
thanks for any advice you can lend,
loosecannon

 

[GRTS]

good point ray.

i just did that, and it seems that some inductors have been changed, and some different cap values, and the switching diodes are now zener diodes? if i have my "symbology" right. LOL
the thing that got me, is that in the MOSFET version, L33 and L37 are marked as resistors on the schem. but they say "L" next to them.
they even have resistance values labeled next to them. L33 is a 1K and L37 is a 10K.
not sure what this means.

so it is more than just doing a MOSFET mod to a bipolar 959. OK.

ray, while i have your ear; are there any upgrades to the current board that you recommend?
i know it will void my warranty, but i will already be doing the 2SB817 and NTE153 upgrades, as well as trying the 2SC2999 mod to see if it agrees with this chassis.
so, my warranty will be shot within a short time of my receipt of the radio anyway.LOL
i WILL be making sure that the radio works properly for a while before i attempt any mods to it.
thanks for any advice you can lend,
loosecannon

L33 and L37 are just resistors with a ferrite bead on one lead to block RF from the DC bias.
The update for that as shown is to replace the L33 and L37 with 22uH chokes.
It doesn't do a lot towards increasing output power.

Quite some time ago we upgraded the 2SB754 with a 2SB827 so you won't need to switch it out for a 2SB817.

The other updates you mention have never shown me much merit but it's your radio.

8)

 

[freecell]

"Won't be long and 1969's will be a thing of the past."

let me know how many you need. i can get you 250,000 pieces every 30 days. it's going to be longer than you think before they're gone.

 

[Switch Kit]

 

[Butcher318]

Thats great to hear, are they the real deal or some ones reproduction? If they are good I might have to get with ya.

 

[loosecannon]

thanks for the advice ray. i appreciate it.

for some reason, on some forums, these radios (galaxy) seem to have a reputation for having a good amount of white noise in the receive.

i have never owned one, and havent had the opportunity to listen to one yet, so i dont know.

i read one thread on here where a guy said to detune a couple of the receive coils to eliminate the white noise.

is this standard practice for aligning these radios?
or did this guy just decrease the sensitivity of his receiver for nothing?

again, thanks for the advice,
loosecannon

 

[TonyV225]

Look at it this way to do the final swap yourself is where the problems of instability may accur but if its done at the factory these are tuned there and Im sure there all good or they woudnt have released them basically they did the work for you and there liable. Galaxy as far as I know has the best warranty policy thats out there its usually a 2 year deal so if anything is wrong with the mosfets you just send it back home for the fix

 

[GRTS]

"Won't be long and 1969's will be a thing of the past."

let me know how many you need. i can get you 250,000 pieces every 30 days. it's going to be longer than you think before they're gone.

I would guess since Mitsubishi has stopped producing 2SC1969 transistors, the "250,000 pieces" you mention are cloned copies. Otherwise Ranger and other manufactures would continue buying them as would larger component part companies like RF Parts.

 

[C2]

maybe they sold the "jig" to a Chinese mfg?