Connex Mod. What is this?

[longhaireddwb]

I bought a Connex 3300HP-zx for a great price. I opened it up to see about doing the NPC mod to it and found TR32 was missing, R246 was cut and a jumper wire from J9 was taken off of somewhere and soldered to R210.

Now "I THINK" (and thats a scarry thing) that the removal of TR32 was to do with the modulation and cutting R246 has to do with it also. Tell me if I'm wrong on this.

As far as the Yellow wire that looks like it should be a J9 and was cut and resoldered to R210 I have no idea about.

Can someone enlighten me about where this yellow wire should be going? I'm going to put TR32 back and fix R246 and put this yellow wire back where it goes before I try the NPC mod.

BTW, This has the 360014B Board in it with the 2 C2312 finals.

Thanks for any help.

 

[longhaireddwb]

I thought that a pic might help so...

You can see the yellow line is actually a yellow wire. It looks original and the solder at the end where it it connected to the board at J9 looks original but it is soldered to the top/bend in R210, not factory.

And if you follow the solder trace at J9 (orange line) it goes to the big plug (J108) that has 14 wires on it. The trace goes to wire labeled RB. From there it goes to the AM/FM/PA pot.

Now I'm just guessing here AGAIN, but would this stand for Roger Beep? There is no Roger Beep controls and when in the TX mode it don't sound off like a Roger Beep at all.

SO..... Can someone enlighten me on what this wire is here for? I've disconnected it and I see no diff in audio of PA or talk back or TX. No diff in the DK on high or low settings, no diff in swing and no diff in frequency output. So.. What do you think?
op:

 

[longhaireddwb]

This is the end of the story.
If your thinking about doing the EPT360014B NPC mod listed here:
npc
Don't bother!

I started by putting everything back to the way it should have been to begin with (except that damn yellow wire soldered to the top of R210) and did this NPC mod. Adding the resister and diode. Removing the cap and installing it on the bottom of the board. Ran the hot wire and pulled the TP7 and TP9 jumpers out of TP8. And a couple other things and it really made no diff compared to just removing TR32 and a nice tune-up.

I'm seeing a swing of about 55 - 60 with 100% modulation. Of course this is keeping the mic gain control turned down a bit because it will over modulate if turned up too much! Dk set at 2 on low and 7 on high.

So I guess it was a nice learning experience. I wish someone could have told me what the damn yellow wire was and where it should go back to OEM but oh well.

Jerry...

 

[ThirstyBoots440]

the NPC mod is more for the average power, it's a decent mod for what it is. I do it on just about every 3600 and 6900 chassis I get.

I've got the same yellow wire on a few 3600 chassis myself, haven't really paid much mind to them.

If I'm not mistaken it's a part of the roger beep system even though they never put one in the connex radios, since so many exports share the 3600 board, the parts are there for the most part. Someone correct me if I'm wrong please.

Honestly I don't find much advantage in volting the finals, and when I do the NPC mod, I change it up a little for better results. If you do this with just a peak reading meter you won't see much difference, it's the average reading you want to look at.