New Galaxy 959 with IRF520 Final- Can you make it a dual?

[RedEye]

I just got one of the newer IRF-520 final 959's. I was going to do the dual 2030 final mod but I'm unsure if the parts listing is correct since it is for a 2sc-1969 swap out.
Does anyone know if and where the directions are to add a IRF-520 and make it a dual? I assume the jumpers to power the 2nd final would be the same but I'm unsure of any other mods that would need to be done.

Also, would the TP8 jumper mod help this radio with the 520 finals? Thanks in advance for picking the great minds out there!!!!
73's and Merry Christmas!

[frogman296]

good observation....the mods don't specify for mosfets...i know the newer breed(HP galaxies), have the empty spot for the second final

[RedEye]

Yes, thats where I want to add it. I am just unsure how to....
Even the cap mods listed are probably wrong, so I don't want to mess with it much yet, just normal screwdriver adjustments with the scope and meter so far. It does make about 24~26 watts now, I am hoping to get 38~40 out of it....

It should be really nice when it's done, I did the +/- 10KC mod and the Channel mod using the tone and PA switches, extended Clarifier mod works great (chan 19 will slide from 27.177 to 27.192) instead of the normal mod that only gets 27.184 to 27.186...

Then I made a new faceplate to show the switches correctly on the front. (tone switch now reads Nor - High - Low for the channels and PA switch reads -10kc / norm / +10kc

[RedEye]

Just finished what I feel safe doing with out info on adding another IRF520

Replaced Q54 with a 2SB817
Replaced Q55 with a 2SA1012
Remove C218
Change C216 (470pf) to a 1000pf (100V mylar-type)
Remove C210
Remove C199 (560pf) and reinstall it in the C210 spot
Removed the jumper for TP 7-8-9 abd soldered TP7-9 Together.
Added a power coil from a 2950 to the positive side and soldered TP8 directly to input voltage( I did this before the power amp change out and did notice a change, however I don't think it is nessesary with the new amp installed... maybe it will be if I find out how to add the second final though... your thoughts?)

The +/- 10KC Mod
Channel Mod
Clarifier Mod

Realigned and adjust the pots... I can adjust DK from .5 watt to 12Watt and the swing is 29~30 Watts now on a Dosey TFC-3001...

I did the cap mods one at a time and checked to see if there was any improvement. All showed a little and none set it backwards, so they seem to be ok with the IRF520

Still hoping someone knows if you can drop in a IRF520 in the second final spot though... I know I'll need to add the jumpers, just wondering if anything else will be needed...
All in all, it's very stable stable on SSB and sounds great on AM as well!

73's

[RedEye]

If anyone has and idea on the dual 520 setups, Let me know, I'm going to put the radio on the shelf till I hear from the great minds out there! Thanks in advance and 73's

[sonoma]

http://www.bills2way.com/modification/ept6900_8719.html

this sight shows the mod for 2 finals.it is for the 2sc1969.you can look at this and see if it will help you.

[Rick]

What is with the blue text it bad for my eyes and did not read it all as it was just too much.

Be warning that IRF520 get very hot and if you use IRF make shore they are all from the same batch and change the driver as well and the caps you need to change need to be NPO type or the best you can find. You are better staying with 2SC1969 or 2SC2312 for as long as you can, but if you must play with MOSFETs then check out the link below.
http://www.cbtricks.com/miscellaneous/f ... 3600xx.pdf

[RedEye]

Thanks Rick, and sorry for the blue text, it was easier to read on my pc.... I know the 520 runs hotter, but it is the new 959 version with one 520 already installed in the driver and final. I wanted to add the remaining 520 in the empty slot.

I also added a temp activated Peltier cooler heat sink to the final mount. It turns on at 80`F and can keep the final at that temp.

I used one before but didn't have a thermal switch and it would actually freeze the back of the radio, and of course cause condensation and damage. The thermal switch eliminated that issue.

I'll look at the link and see if it will clue me to adding the final. Thanks again for your input. You are a great help to us!!!!!

The attachment is the new faceplate I made

73's

[speedracer6g]

the dx 98 vhp has the same board. if you look at the schematic for the dx-98vhp the main board is dual mosfet and should get you well on you way. Make sure the 3rd leg of the bias pot is soldered to ground on the driver circuit. If you dont do that you wont be able to set your bias on the driver to 3.6 volts. If i remember i could not get below 4.2 volts.

http://www.cbtricks.com/radios/galaxy/d ... hp_sch.pdf

MIKE

PS let us know how you make out. I am Doing one of these radio sometime this week. I have done some of the 3600 series boards but none of these new ones yet. So i will be venturing down this road as well.

[GRTS]

the dx 98 vhp has the same board. if you look at the schematic for the dx-98vhp the main board is dual mosfet and should get you well on you way. Make sure the 3rd leg of the bias pot is soldered to ground on the driver circuit. If you dont do that you wont be able to set your bias on the driver to 3.6 volts. If i remember i could not get below 4.2 volts.

http://www.cbtricks.com/radios/galaxy/d ... hp_sch.pdf

MIKE

PS let us know how you make out. I am Doing one of these radio sometime this week. I have done some of the 3600 series boards but none of these new ones yet. So i will be venturing down this road as well.

Your link goes to the DX94HP which is one IRF520 driver and one IRF520 final.

[speedracer6g]

Sorry about that i didnt even notice it was the wrong shcematic. thanks GRTS.

http://www.cbtricks.com/radios/galaxy/d ... hp_sch.pdf

this should help you out.

MIKE

[speedracer6g]

I am working on a tutorial for this mod. I would recomend using two mosfets for the main finals. that way they are from the same batch. Q47 and Q48. There are some changes you need to make to the driver section on this radio after you install the finals as well. It has to do with L38 and L35. If you or anybodyelse has interest let me know and I will try to write someting up on it. I dont want to waist time if nobody is interested but from the looks of things some people are intersted. With my results on the last radio i upgraded i acheaved 56 watts Pep with the dual final upgrade. Stock was only around 24 or 25 pep. If you install just the finals and dont make any changes to the driver you will only see about 40 watts pep. or 20 watts on a dosy type meter. With this upgrade you can set your deadkey to 10 and swing from there with plenty of clean modulation. let me know guys and i will see what i can work up.

MIKE

[speedracer6g]

i have a worksheet on how to mod your galaxy DX-959 to have dual mosfets. I just wrote it up so there may be some gramatical errors. I am having trouble uploading it here to this site. I anybody wants it just email me and i will send it to you.

Mike

mike@mynovasecurity.com

email me with any questions.

[Rick]

The info to help you can be found on CBTricks.
I know it is for the 3600x chassis but it will help.
http://www.cbtricks.com/miscellaneous/f ... 3600xx.pdf

[speedracer6g]

The problem with the mod paper on cbtricks is that some of the components are different and need edited. the 1n4148 for instance needs to be a 5.6volt zener and there are a couple of other things too. I looked at this mod before and tested it with the zeners and place and got less than desirable results. My mod is more or less a clone of the 33hp. No secrets here. Ha ha . I dont remember if i contacted cbtricks about the component issue or not. I guess i will have to check on that. As always thanks for the input rick

MIKE