• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Galaxy DX-959 NPC-RC Mod


This is what I found. :D This is a copy and paste.

This trick will apply to most SSB and Export type radios only including the 148 GTL, 2000 GTL, Grant XL & LT, Galaxy, Connex, Superstar, RCI and more. The mods will be listed by board number, not radio model, so make sure you make a note of the board number that is stamped on the main PCBoard of your radio..... The diode is a 1N4001. If for any reason this mod doesn't do what it should, check the polarity of the diode. Banded end is the Cathode! You can remove the resistor completely and solder the diode in its place, but do not recommend this. If you really want to replace the resistor with the diode, do not run the power completely down (no dead key), this could cause faults in the AM Modulation Stage. When lifting the end of the resistor, solder the banded end of diode in its place (where it used to be), the other end of diode solders to the lifted end of the resistor.

*EPT014811Z, PC411, PC412 (Uniden Grant XL, Uniden Madison, Cobra 148/2000 GTL, Teaberry Stalker 20 Export, Texas Ranger TR296 etc...)
-Lift the end of R228 that connects to TR42. Place the cathode
(banded end) of the diode towards TR42 and solder the other end to the lifted end of R228. Thats it!

*(PC-385) Cobra 140 GTL, Teaberry Stalker IX, Realistic TRC-490, Uniden/President Washington (8719), Cobra 142GTL and maybe others
-Lift the end of R121 that connects to VR6. Solder Banded end of diode to lifted end of resistor and other end of diode back in the hole where the resistor was lifted. This info has not been tested and the schematic shows differences not typical with a radio like above or below. Most of the other radios have a 560 ohm resistor and diode in parrallel with each other, this radio does not, so the info should work, but I cannot guarantee it.... Please verify that the above radios use VR6 as AM Power Control. If any changes need to be made or a radio needs to be removed or added, please let me know...

*EPT360014, EPT360011 (Galaxy, Connex, Superstar and more. Excalibur SSB)
-Lift end of R240 that connects to C189 & C188. Solder banded end of diode towards C188 and other end to lifted end of R240. Check for peak power at low power setting and see if it matches the peak at high.

*EPT069610Z (Galaxy DX959/949/2547, Texas Ranger 696F SSB, 696F, 396, 936, 966)
-Lift end of R266 that connects to D103 and C233. Solder the banded end in the empty hole where resistor was lifted and solder the other end of diode to lifted end of resistor. (CORRECTION submitted by Mav391: Cap number is C233, not C133 as earlier listed - Thank you for the updated info!)

*EPT295013Z (RCI 2950/2970 (Not DX))
-Lift end of resistor R285 that connects to C300 & C303. Solder banded end of diode to the empty hole going to C300 & C303, solder other end of diode to lifted end of resistor.

*EPT690010Z
-R266 - This is done exactly the same as the 959/949 and 2547. These boards are identical in every way except the exclusion of FM and the PLL area is different.

*EPT990010Z Ranger RCI-6900FHP
-Lift end of R292 that connects to C261 and C255. Solder the banded end in the empty hole where resistor was lifted and solder the other end of diode to lifted end of resistor.

*PC999 President Grant Export
-Lift end of resistor R282 where it connect to C217. Solder banded end of diode in the hole and solder the other end to the lifted resistor.

*PC833 Cobra 146 GTL, Uniden AR144 & AX144
-Lift end of R212 that connects to C180. Solder banded end in hole and other end to lifted end of resistor.

*Clear Channel Ranger AR-3500
-Lift end of R249 and place banded end of diode towards Q34. I have heard this will also work with R224 as well.....

*PC893 - Stalker 9 FDX R255

*PC965 R212

If anyone has the schematic for the PC965, PB062, PB042, PB122 boards, feel free to e-mail them to me and I can update the rest of the info for them.

UPDATE: You can use the info as above or you can try this on your own. I and Toll Free have tried this on our radios and achieved a bigger increase. Toll Free used a President Grant Export and a RMS Bird Meter. His results were as follows.....

1 watt dead key and swing to 8 before, 1 watt dead key and swing pegged the 10 watt scale. On a Yaesu YC-60 Meter, his peak was at 40 watts. Remember this was a Grant Export...

My results were found using my Stalker 20 (PC-411AD) and an Astatic 600 Test Meter as follows....

6 watt dead key swing 18 before, 6 watt dead key swing to 23 after.

If you are wondering what we did, here it is.... Just remove the resistor and put the diode in its place completely instead of hooking them up in series.
Good luck and enjoy the info! WCR
 
  • Like
Reactions: Slowmover and Robb
The audio on the 959 is pretty good to start with, I wouldn't see any reason to do a npc mod.[/QUOTE
agee with ya very much. and i doubt any average joe hasd all
the proper equiment to even attempt tring it. btw ones ive heard
with it done are overmodulated on am .and even worse on ssb to the
point they were almost unusable
 
btw ones ive heard
with it done are overmodulated on am .and even worse on ssb to the
point they were almost unusable

I am only replying to this statement, certainly not arguing against it, but it seems to me most over-modulation issues such as this one are easily remedied by turning down the mic gain. When this is done it undoubtedly indicates it wasn't an issue with the mod, but with the ineptitude of the operator.

I have done this mod on at least three radios with no idea it was the NPC-RC mod. In every case I achieved the goal of enhancing the performance of the radio, and in every case I sacrificed no perceivable quality in performance. I did not have a scope to work with, and the resource from which I got the mod information never indicated I needed one. Perhaps I would have done well to have had one. Likely, I would never have attempted it without the high end tools suggested. Once the parts were in place I simply tuned for best power and froward on the operating band. Then I set low power at 1 watt, and high at 6 watts on the 88's and 959 I did this on. The next step was to ask someone I trusted to give me an answer regarding the quality of my audio as opposed to only the loudness of the same to set my mic gain, and I was on the air with great performance and great sound on both AM and SSB.

If I had known I was doing the greatly debated NPC-RC mod I may have hesitated to use it. Then I would have seen it was so simple I would have gotten beyond the hesitant moment and done it anyway, if this is really the NPC-RC mod. :confused:

My only question here is whether this simple 1N4001 diode and resistor change is really what all the talk has been about? If so, at least the changes are much more reliably able to be documented for performance improvement than buying the latest and greatest in antennas.

2¢ from Homer, but then again, I really don't know anything about NPC-RC mods :sad:
 
  • Like
Reactions: 2 people
*EPT069610Z (Galaxy DX959/949/2547, Texas Ranger 696F SSB, 696F, 396, 936, 966)
-Lift end of R266 that connects to D103 and C233. Solder the banded end in the empty hole where resistor was lifted and solder the other end of diode to lifted end of resistor. (CORRECTION submitted by Mav391: Cap number is C233, not C133 as earlier listed - Thank you for the updated info!)



I have done this Swing mod on my 959 and TR696F it is NOT R266 IT IS R264!

and it works Great.
 
  • Like
Reactions: 1 person
Did this mod on a FredomOne by Ranger twice. First time i did it was with a 1n4007 diode.(only diode type I had.) Didn't work. Audio was distorted. Bought a bunch of diodes from Radio Shack. Put the 1n4001 as specified in this post.
BOY DOES THIS THING MOVE NOW !!!!!!!!!!
Dead Key 1 watt RMS
RMS Swing of 8 watts
Audio Loud and Clear !
On RMS/Avg setting, it makes my meters do sit ups when I talk !!!!
Thanks for the post and sharing this info.
 
  • Like
Reactions: Enterprise312ok

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Tucker442 has left the room.
  • @ BJ radionut:
    LIVE 10:00 AM EST :cool:
  • @ Charles Edwards:
    I'm looking for factory settings 1 through 59 for a AT 5555 n2 or AT500 M2 I only wrote down half the values feel like a idiot I need help will be appreciated